Add historical analysis diffing for same-company runs

- Add GET /analyze/{company_name}/diff endpoint with from/to query params
- Add GET /analyze/{company_name}/history endpoint for run selection
- Add database methods get_analysis_by_id and list_company_analyses
- Add frontend HistoryDiff page with run selector and diff visualization
- Add Compare with previous button on Analysis results page
- Add navigation link in Layout sidebar
- Add 11 tests covering helpers, happy-path, and 404 scenarios

Closes leeworks-agents/SPARC#1671

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ROADMAP.md

@@ -7,86 +7,124 @@ Semiconductor Patent & Analytics Report Core -- development priorities.
 SPARC is a patent analysis platform with a working end-to-end pipeline:
 Python/FastAPI backend, React/TypeScript frontend, PostgreSQL for persistence
 and caching, Docker Compose for local development, and Gitea Actions CI/CD for
-image builds. Core features (patent retrieval via SerpAPI, PDF parsing, LLM
-analysis via OpenRouter/Claude, batch processing, JWT authentication, analytics
-dashboard) are all implemented and functional.
+image builds and testing. Core features include patent retrieval via SerpAPI,
+PDF parsing, LLM analysis via OpenRouter (multi-model: Claude, GPT-4o, Gemini,
+Llama), batch processing, JWT authentication, analytics dashboard with patent
+trend charts, scheduled recurring analysis with alerting, webhook notifications
+(Slack/Discord), CSV and PDF export, S3/MinIO storage, side-by-side company
+comparison, and dark mode.
+
+---
+
+## Completed
+
+Items that have been implemented and merged into main.
+
+### Security hardening
+
+- ~~Rotate default JWT secret.~~ Startup check refuses to start with the
+  default secret in non-development environments.
+- ~~CORS allow-origins are hardcoded.~~ Allowed origins are now configurable
+  via environment variable.
+- ~~Database credentials in docker-compose.yml.~~ Compose references `.env`
+  for sensitive values.
+
+### Error handling and resilience
+
+- ~~`get_db_client()` creates a new `DatabaseClient` on every call.~~ Refactored
+  to a shared pooled singleton initialized at startup.
+- ~~No rate limiting on auth endpoints.~~ Rate limiting middleware added to
+  `/auth/login` and `/auth/register`.
+
+### Test coverage
+
+- ~~API tests bypass authentication.~~ JWT auth integration tests added (33
+  cases covering registration, login, protected routes, token refresh, and
+  admin-only endpoints).
+- ~~No test stage in CI.~~ Gitea Actions workflow now runs `pytest` and gates
+  the build.
+- ~~No linting or type checking in CI.~~ `ruff` (Python) and `tsc --noEmit`
+  (TypeScript) added to CI pipeline.
+
+### Backend
+
+- ~~Add structured logging.~~ Python `logging` module used throughout.
+- ~~Make LLM model configurable.~~ `MODEL` environment variable accepted;
+  multi-model support with per-analysis selection (GPT-4o, Gemini, Claude,
+  Llama).
+- ~~SERP cache TTL hardcoded.~~ `SERP_CACHE_TTL_HOURS` exposed as env var.
+- ~~Patent PDF storage.~~ S3/MinIO object storage backend added alongside
+  local filesystem. Volume mount requirement documented.
+- ~~`analyze_single_patent` assumes local file.~~ Auto-download from cached
+  metadata link integrated.
+- ~~`Patent.patent_id` typed as `int`.~~ Fixed to `str`.
+
+### Frontend
+
+- ~~No loading/error states.~~ Skeleton loaders and error states added to
+  Batch and Analytics pages.
+- ~~No dark mode.~~ Full dark mode support with theme-aware chart colors.
+- ~~Missing lockfile.~~ `package-lock.json` committed.
+
+### Features (formerly P3)
+
+- ~~Export analysis reports.~~ CSV and PDF export endpoints implemented.
+- ~~Comparison view.~~ Side-by-side company patent portfolio comparison added.
+- ~~Scheduled/recurring analysis.~~ APScheduler-based periodic re-analysis
+  with configurable interval and change-threshold alerting.
+- ~~Webhook/notification support.~~ Slack, Discord, and generic HTTP POST
+  webhooks with retry logic.
+- ~~Multi-model support.~~ Model picker in Analysis and Batch pages; backend
+  allow-list validation.
+- ~~Patent trend charts.~~ Filing frequency and category distribution
+  visualizations added to Analytics page.
+- ~~OpenAPI client generation.~~ TypeScript API client auto-generated from
+  FastAPI spec with CI freshness check.
+
+### Resilience
+
+- ~~`_jobs` dict is in-memory only.~~ Database-backed job persistence
+  implemented using `db.list_jobs()` and `mark_stale_jobs_failed()`. The
+  in-memory `_jobs` dict has been removed.
+
+### Test coverage (P1/P2)
+
+- ~~Export endpoint tests.~~ Tests added for CSV and PDF export endpoints.
+- ~~Tracked company admin endpoint tests.~~ Tests added for `/admin/tracked`
+  CRUD endpoints and scheduler integration.
+- ~~Webhook integration tests.~~ Tests added for retry logic, Slack/Discord
+  payload format, and multi-URL dispatch.
+- ~~S3/MinIO storage backend tests.~~ Unit tests added for the S3 backend
+  (read, write, exists, delete, error handling).
+- ~~`analyze_single_patent` auto-download path tests.~~ Tests added for the
+  auto-download fallback (cache lookup, PDF download, FileNotFoundError).
+
+### Code quality
+
+- ~~Scheduler creates its own DatabaseClient.~~ Refactored to use the
+  application-level pooled `get_db_client()`.
 
 ---
 
 ## P1 -- High Priority
 
-These items address correctness, security, and reliability gaps that should be
-resolved before broader production use.
-
-### Security hardening
-
-- **Rotate default JWT secret.** `auth.py` ships a fallback
-  `sparc-secret-key-change-in-production` that will be used if `JWT_SECRET` is
-  unset. Add a startup check that refuses to start with the default secret in
-  non-development environments.
-- **CORS allow-origins are hardcoded.** `api.py` only permits
-  `localhost:3000` and `localhost:5173`. Make the allowed origins configurable
-  via environment variable so the dashboard works when deployed behind a real
-  domain.
-- **Database credentials in docker-compose.yml.** The compose file embeds
-  `postgres:postgres` in plain text. Reference a `.env` file or Docker secrets
-  instead.
-
-### Error handling and resilience
-
-- **`get_db_client()` in `auth.py` creates a new `DatabaseClient` on every
-  call.** This bypasses the connection pool and can exhaust database
-  connections under load. Refactor to share a single pooled client.
-- **`_jobs` dict is in-memory only.** Job state is lost on API restart. Persist
-  job status in PostgreSQL or Redis so async batch results survive restarts.
-- **No rate limiting on auth endpoints.** `/auth/login` and `/auth/register`
-  are unprotected against brute-force or abuse. Add rate limiting middleware.
-
-### Test coverage for auth and admin
-
-- The existing API tests (`tests/test_api.py`) bypass authentication entirely.
-  Add tests that exercise the JWT flow: registration, login, protected-route
-  access, token refresh, and admin-only endpoints.
+No outstanding P1 items. All previously listed items have been completed and
+moved to the Completed section above.
 
 ---
 
 ## P2 -- Medium Priority
 
-Improvements to usability, performance, and developer experience.
+Improvements to the API surface.
 
-### Backend
+### API improvements
 
-- **Add structured logging.** Replace `print()` calls throughout `analyzer.py`,
-  `serp_api.py`, and `llm.py` with Python `logging` so log levels and
-  formatting are consistent.
-- **Make LLM model configurable.** `llm.py` hardcodes
-  `anthropic/claude-3.5-sonnet`. Accept a `MODEL` environment variable to allow
-  switching models without code changes.
-- **SERP cache TTL is hardcoded to 24 hours.** Expose `SERP_CACHE_TTL_HOURS`
-  as an environment variable in `config.py`.
-- **Patent PDF storage.** PDFs are saved to a local `patents/` directory. For
-  containerized deployments, consider object storage (S3/MinIO) or at minimum
-  document the volume mount requirement more prominently.
-- **`analyze_single_patent` assumes local file path.** The method constructs
-  `patents/{patent_id}.pdf` and reads from disk, but does not download the PDF
-  first. Either integrate the download step or document the prerequisite.
-- **`Patent.patent_id` typed as `int` in `types.py` but used as `str`
-  everywhere.** Fix the type annotation to `str`.
-
-### Frontend
-
-- **No loading/error states on several pages.** The Batch and Analytics pages
-  would benefit from skeleton loaders and user-friendly error messages.
-- **No dark mode.** Tailwind is configured but no dark variant is applied.
-- **Missing `package-lock.json` or `pnpm-lock.yaml`.** The frontend has no
-  lockfile committed, leading to non-reproducible builds.
-
-### CI/CD
-
-- **No test stage in the Gitea Actions workflow.** `build.yaml` builds and
-  pushes images but never runs `pytest`. Add a test job that gates the build.
-- **No linting or type checking.** Add `ruff` (Python) and `tsc --noEmit`
-  (TypeScript) to CI.
+- **API pagination.** The `/analyze/batch` endpoint needs cursor-based
+  pagination for large result sets. The `/jobs` endpoint already has cursor
+  pagination. *(Issue #1669)*
+- **Request validation improvements.** Add stricter input validation for
+  company names (disallow special characters, enforce length limits).
+  *(Issue #1670)*
 
 ---
 
@@ -94,23 +132,20 @@ Improvements to usability, performance, and developer experience.
 
 Lower-urgency enhancements and future features.
 
-- **Export analysis reports.** Allow users to download analysis results as PDF
-  or CSV from the dashboard.
-- **Comparison view.** Side-by-side comparison of two companies' patent
-  portfolios.
-- **Scheduled/recurring analysis.** Periodically re-analyze tracked companies
-  and alert on significant changes.
-- **Webhook/notification support.** Send alerts (Slack, Discord, email) when
-  batch jobs complete or when a company's innovation score changes
-  significantly.
-- **Multi-model support.** Let users choose between LLM providers per analysis
-  (e.g., GPT-4o, Gemini, Claude) and compare outputs.
-- **Patent trend charts.** Visualize patent filing frequency and technology
-  category distribution over time in the Analytics page.
-- **API pagination.** The `/analyze/batch` and `/jobs` endpoints could benefit
-  from cursor-based pagination for large result sets.
-- **OpenAPI client generation.** Auto-generate the TypeScript API client from
-  the FastAPI OpenAPI spec to keep frontend types in sync.
+- **Historical analysis diffing.** Show what changed between two analysis runs
+  for the same company, highlighting new patents and score shifts.
+- **Patent classification tagging.** Automatically tag patents by technology
+  domain (AI, semiconductors, materials science) using LLM classification.
+- **User-level API keys.** Allow users to generate personal API keys for
+  programmatic access without JWT token refresh.
+- **Batch export.** Export analysis results for multiple companies at once as
+  a ZIP archive.
+- **Rate limiting dashboard.** Surface rate limit status and usage statistics
+  in the admin panel.
+- **Async webhook delivery.** Move webhook delivery to a background task queue
+  (e.g., Celery, arq) to avoid blocking the scheduler.
+- **Multi-tenant support.** Scope analysis results and tracked companies per
+  user or organization.
 
 ---
 

SPARC/api.py

@@ -5,17 +5,18 @@ Provides REST API endpoints for analyzing company patent portfolios.
 
 from __future__ import annotations
 
+from collections import deque
 from contextlib import asynccontextmanager
-from datetime import datetime
+from datetime import datetime, timedelta, timezone
 from typing import TYPE_CHECKING, Annotated, List
 
 if TYPE_CHECKING:
     from SPARC.database import DatabaseClient
 
-from fastapi import BackgroundTasks, Depends, FastAPI, HTTPException, Query, Request
+from fastapi import BackgroundTasks, Depends, FastAPI, HTTPException, Path, Query, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import JSONResponse, StreamingResponse
-from pydantic import BaseModel, EmailStr, Field
+from pydantic import BaseModel, EmailStr, Field, StringConstraints
 from slowapi import Limiter
 from slowapi.errors import RateLimitExceeded
 from slowapi.util import get_remote_address
@@ -29,13 +30,25 @@ from SPARC.auth import (
     close_db_client,
     create_tokens,
     decode_token,
+    generate_api_key,
     get_current_admin,
     get_current_user,
     get_db_client,
+    hash_api_key,
     init_db_client,
 )
 from SPARC.types import BatchAnalysisResult, CompanyAnalysisResult
 
+# Validated company name type: 2-100 chars, alphanumeric + spaces/hyphens/ampersands/periods only.
+CompanyName = Annotated[
+    str,
+    StringConstraints(
+        min_length=2,
+        max_length=100,
+        pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$",
+    ),
+]
+
 
 # Pydantic models for API
 class CompanyAnalysisResponse(BaseModel):
@@ -72,7 +85,7 @@ class CompanyAnalysisRequest(BaseModel):
 class BatchAnalysisRequest(BaseModel):
     """Request model for batch company analysis."""
 
-    companies: list[str] = Field(
+    companies: list[CompanyName] = Field(
         ..., min_length=1, max_length=20, description="List of company names to analyze"
     )
     max_workers: int = Field(
@@ -96,6 +109,24 @@ class JobStatus(BaseModel):
     error: str | None = None
 
 
+class AnalysisRecord(BaseModel):
+    """A single stored analysis result."""
+
+    id: int
+    company_name: str | None = None
+    analysis_type: str | None = None
+    model: str | None = None
+    response: str | None = None
+    timestamp: datetime | None = None
+
+
+class PaginatedAnalysisResponse(BaseModel):
+    """Paginated response for analysis result listings."""
+
+    items: list[AnalysisRecord]
+    next_cursor: str | None = None
+
+
 class PaginatedJobsResponse(BaseModel):
     """Paginated response for job listings."""
 
@@ -111,6 +142,31 @@ class HealthResponse(BaseModel):
     timestamp: datetime
 
 
+# Historical diff models
+class AnalysisDiffResponse(BaseModel):
+    """Response model for diffing two analysis runs of the same company."""
+
+    company_name: str
+    from_id: int
+    to_id: int
+    from_timestamp: datetime
+    to_timestamp: datetime
+    patent_count_delta: int
+    added_patents: list[str]
+    removed_patents: list[str]
+    changed_fields: dict[str, dict]
+    summary: str
+
+
+class CompanyAnalysisHistoryItem(BaseModel):
+    """A summary item from a company's analysis history."""
+
+    id: int
+    analysis_type: str | None = None
+    model: str | None = None
+    timestamp: datetime
+
+
 # Auth request/response models
 class RegisterRequest(BaseModel):
     """User registration request."""
@@ -217,10 +273,45 @@ app = FastAPI(
 limiter = Limiter(key_func=get_remote_address)
 app.state.limiter = limiter
 
+# In-memory rate limit statistics
+_rate_limit_stats: dict[str, dict] = {}
+
+# Time-series log of rejected requests (capped to last 24 h worth of entries).
+_rejected_log: deque[dict] = deque(maxlen=100_000)
+
+
+def _track_rate_limit_request(endpoint: str, ip: str, rejected: bool = False) -> None:
+    """Record a request against a rate-limited endpoint."""
+    key = endpoint
+    if key not in _rate_limit_stats:
+        _rate_limit_stats[key] = {
+            "endpoint": endpoint,
+            "total_requests": 0,
+            "rejected_requests": 0,
+            "by_ip": {},
+        }
+    _rate_limit_stats[key]["total_requests"] += 1
+    if rejected:
+        _rate_limit_stats[key]["rejected_requests"] += 1
+        _rejected_log.append({
+            "endpoint": endpoint,
+            "ip": ip,
+            "timestamp": datetime.now(timezone.utc).isoformat(),
+        })
+    ip_stats = _rate_limit_stats[key].setdefault("by_ip", {})
+    if ip not in ip_stats:
+        ip_stats[ip] = {"total": 0, "rejected": 0}
+    ip_stats[ip]["total"] += 1
+    if rejected:
+        ip_stats[ip]["rejected"] += 1
+
 
 @app.exception_handler(RateLimitExceeded)
 async def rate_limit_handler(request: Request, exc: RateLimitExceeded):
     """Return 429 with Retry-After header when rate limit is exceeded."""
+    endpoint = request.url.path
+    ip = get_remote_address(request)
+    _track_rate_limit_request(endpoint, ip, rejected=True)
     retry_after = getattr(exc, "retry_after", 60)
     return JSONResponse(
         status_code=429,
@@ -249,6 +340,7 @@ async def register(request: Request, body: RegisterRequest):
 
     The first registered user automatically becomes an admin.
     """
+    _track_rate_limit_request("/auth/register", get_remote_address(request))
     db = get_db_client()
 
     # First user becomes admin
@@ -279,6 +371,7 @@ async def register(request: Request, body: RegisterRequest):
 @limiter.limit("10/minute")
 async def login(request: Request, body: LoginRequest):
     """Authenticate user and return JWT tokens."""
+    _track_rate_limit_request("/auth/login", get_remote_address(request))
     db = get_db_client()
 
     user = db.authenticate_user(body.email, body.password)
@@ -321,6 +414,92 @@ async def get_me(current_user: UserResponse = Depends(get_current_user)):
     return current_user
 
 
+# ============== API Key Endpoints ==============
+
+
+class CreateApiKeyRequest(BaseModel):
+    """Request to create a new API key."""
+
+    label: str | None = Field(default=None, max_length=100, description="Optional label for the key")
+
+
+class ApiKeyResponse(BaseModel):
+    """Response after creating an API key (includes plaintext key)."""
+
+    id: int
+    key: str  # plaintext key, shown only at creation time
+    label: str | None = None
+    created_at: datetime
+
+
+class ApiKeyInfo(BaseModel):
+    """API key metadata (no secret)."""
+
+    id: int
+    label: str | None = None
+    created_at: datetime
+
+
+@app.post("/auth/apikeys", response_model=ApiKeyResponse, tags=["Auth"])
+async def create_api_key_endpoint(
+    body: CreateApiKeyRequest | None = None,
+    current_user: UserResponse = Depends(get_current_user),
+):
+    """Generate a new API key for the authenticated user.
+
+    The plaintext key is returned **only once** in the response.
+    Store it securely; it cannot be retrieved again.
+    """
+    plaintext_key = generate_api_key()
+    key_hash = hash_api_key(plaintext_key)
+
+    db = get_db_client()
+    label = body.label if body else None
+    row = db.create_api_key(
+        user_id=current_user.id,
+        key_hash=key_hash,
+        label=label,
+    )
+
+    return ApiKeyResponse(
+        id=row["id"],
+        key=plaintext_key,
+        label=row["label"],
+        created_at=row["created_at"],
+    )
+
+
+@app.get("/auth/apikeys", response_model=list[ApiKeyInfo], tags=["Auth"])
+async def list_api_keys_endpoint(
+    current_user: UserResponse = Depends(get_current_user),
+):
+    """List active API key IDs and labels for the authenticated user.
+
+    Does **not** return the secret keys.
+    """
+    db = get_db_client()
+    keys = db.list_api_keys(current_user.id)
+    return [ApiKeyInfo(**k) for k in keys]
+
+
+@app.delete("/auth/apikeys/{key_id}", tags=["Auth"])
+async def revoke_api_key_endpoint(
+    key_id: int,
+    current_user: UserResponse = Depends(get_current_user),
+):
+    """Revoke (delete) an API key by its ID.
+
+    The key must belong to the authenticated user.
+    """
+    db = get_db_client()
+    deleted = db.delete_api_key(key_id, current_user.id)
+
+    if not deleted:
+        raise HTTPException(status_code=404, detail="API key not found")
+
+    return {"message": "API key revoked"}
+
+
 # ============== Admin Endpoints ==============
 
 
@@ -405,7 +584,7 @@ async def delete_user(
 class TrackCompanyRequest(BaseModel):
     """Request to add a company to tracking."""
 
-    company_name: str = Field(..., min_length=1, max_length=255)
+    company_name: CompanyName = Field(...)
 
 
 @app.get("/admin/tracked", tags=["Admin"])
@@ -432,7 +611,7 @@ async def add_tracked_company(
 
 @app.delete("/admin/tracked/{company_name}", tags=["Admin"])
 async def remove_tracked_company(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_admin),
 ):
     """Remove a company from the tracked list (admin only)."""
@@ -443,6 +622,69 @@ async def remove_tracked_company(
     return {"message": f"Stopped tracking {company_name}"}
 
 
+@app.get("/admin/rate-limits", tags=["Admin"])
+async def get_rate_limit_stats(
+    _: UserResponse = Depends(get_current_admin),
+):
+    """Get rate limit status and usage statistics (admin only).
+
+    Returns current rate limit configuration and request statistics
+    for all rate-limited endpoints, including per-IP breakdown and
+    a time-series of throttled (rejected) requests in the last 24 hours.
+
+    Returns:
+        Rate limit stats per endpoint, per-IP breakdown, and throttled
+        request history bucketed by hour.
+    """
+    rate_limits_config = {
+        "/auth/register": {"limit": "5/minute"},
+        "/auth/login": {"limit": "10/minute"},
+    }
+
+    results = []
+    for endpoint, conf in rate_limits_config.items():
+        stats = _rate_limit_stats.get(endpoint, {})
+        by_ip_raw = stats.get("by_ip", {})
+        by_ip = [
+            {"ip": ip, "total": counts["total"], "rejected": counts["rejected"]}
+            for ip, counts in by_ip_raw.items()
+        ]
+        results.append({
+            "endpoint": endpoint,
+            "limit": conf["limit"],
+            "total_requests": stats.get("total_requests", 0),
+            "rejected_requests": stats.get("rejected_requests", 0),
+            "by_ip": by_ip,
+        })
+
+    # Build hourly buckets of throttled requests for the last 24 hours
+    now = datetime.now(timezone.utc)
+    cutoff = now - timedelta(hours=24)
+    hourly_buckets: dict[str, int] = {}
+    throttled_24h = 0
+    for entry in _rejected_log:
+        ts_str = entry["timestamp"]
+        try:
+            ts = datetime.fromisoformat(ts_str)
+        except (ValueError, TypeError):
+            continue
+        if ts >= cutoff:
+            throttled_24h += 1
+            bucket = ts.strftime("%Y-%m-%dT%H:00:00Z")
+            hourly_buckets[bucket] = hourly_buckets.get(bucket, 0) + 1
+
+    throttled_over_time = [
+        {"timestamp": k, "count": v}
+        for k, v in sorted(hourly_buckets.items())
+    ]
+
+    return {
+        "rate_limits": results,
+        "throttled_24h": throttled_24h,
+        "throttled_over_time": throttled_over_time,
+    }
+
+
 @app.get("/admin/alerts", tags=["Admin"])
 async def list_alerts(
     limit: int = Query(default=50, ge=1, le=200),
@@ -590,7 +832,7 @@ async def get_analytics_trends(
 
 @app.get("/export/{company_name}", tags=["Export"])
 async def export_company_csv(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Export analysis results for a company as a CSV file.
@@ -642,7 +884,7 @@ async def export_company_csv(
 
 @app.get("/export/{company_name}/pdf", tags=["Export"])
 async def export_company_pdf(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Export analysis results for a company as a formatted PDF report.
@@ -816,7 +1058,7 @@ async def health_check():
     tags=["Analysis"],
 )
 async def analyze_company(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     model: str | None = Query(default=None, description="LLM model to use (e.g. 'openai/gpt-4o'). Defaults to server config."),
     _: UserResponse = Depends(get_current_user),
 ):
@@ -840,13 +1082,154 @@ async def analyze_company(
     return _convert_result(result)
 
 
+def _extract_patent_ids(response_text: str) -> set[str]:
+    """Extract patent IDs from an analysis response text.
+
+    Looks for patterns like US-12345678-B2, US12345678B2, etc.
+    """
+    import re
+    pattern = r"US[-\s]?\d{7,8}[-\s]?[A-Z]\d?"
+    return set(re.findall(pattern, response_text or ""))
+
+
+def _compute_analysis_diff(from_rec: dict, to_rec: dict) -> AnalysisDiffResponse:
+    """Compute a structured diff between two analysis records."""
+    from_patents = _extract_patent_ids(from_rec.get("response", "") or "")
+    to_patents = _extract_patent_ids(to_rec.get("response", "") or "")
+
+    added = sorted(to_patents - from_patents)
+    removed = sorted(from_patents - to_patents)
+
+    patent_count_delta = len(to_patents) - len(from_patents)
+
+    changed_fields: dict[str, dict] = {}
+    if from_rec.get("model") != to_rec.get("model"):
+        changed_fields["model"] = {
+            "from": from_rec.get("model"),
+            "to": to_rec.get("model"),
+        }
+    if from_rec.get("analysis_type") != to_rec.get("analysis_type"):
+        changed_fields["analysis_type"] = {
+            "from": from_rec.get("analysis_type"),
+            "to": to_rec.get("analysis_type"),
+        }
+
+    # Build a human-readable summary
+    parts: list[str] = []
+    if added:
+        parts.append(f"{len(added)} new patent(s) appeared")
+    if removed:
+        parts.append(f"{len(removed)} patent(s) no longer referenced")
+    if patent_count_delta > 0:
+        parts.append(f"patent mention count increased by {patent_count_delta}")
+    elif patent_count_delta < 0:
+        parts.append(f"patent mention count decreased by {abs(patent_count_delta)}")
+    if changed_fields:
+        parts.append(f"field(s) changed: {', '.join(changed_fields.keys())}")
+    summary = "; ".join(parts) if parts else "No significant differences detected."
+
+    return AnalysisDiffResponse(
+        company_name=to_rec["company_name"],
+        from_id=from_rec["id"],
+        to_id=to_rec["id"],
+        from_timestamp=from_rec["timestamp"],
+        to_timestamp=to_rec["timestamp"],
+        patent_count_delta=patent_count_delta,
+        added_patents=added,
+        removed_patents=removed,
+        changed_fields=changed_fields,
+        summary=summary,
+    )
+
+
+@app.get(
+    "/analyze/{company_name}/history",
+    response_model=list[CompanyAnalysisHistoryItem],
+    tags=["Analysis"],
+)
+async def list_company_analysis_history(
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
+    limit: int = Query(default=20, ge=1, le=100),
+    _: UserResponse = Depends(get_current_user),
+):
+    """List previous analysis runs for a company.
+
+    Returns a list of analysis records ordered by timestamp descending,
+    useful for selecting which runs to compare via the diff endpoint.
+
+    Args:
+        company_name: Company name to look up
+        limit: Maximum number of results
+
+    Returns:
+        List of analysis history items
+    """
+    db = _get_job_db()
+    rows = db.list_company_analyses(company_name, limit=limit)
+    return [
+        CompanyAnalysisHistoryItem(
+            id=r["id"],
+            analysis_type=r.get("analysis_type"),
+            model=r.get("model"),
+            timestamp=r["timestamp"],
+        )
+        for r in rows
+    ]
+
+
+@app.get(
+    "/analyze/{company_name}/diff",
+    response_model=AnalysisDiffResponse,
+    tags=["Analysis"],
+)
+async def diff_company_analyses(
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
+    from_id: int = Query(..., alias="from", description="Analysis ID of the older run"),
+    to_id: int = Query(..., alias="to", description="Analysis ID of the newer run"),
+    _: UserResponse = Depends(get_current_user),
+):
+    """Compare two analysis runs for the same company.
+
+    Returns a structured diff showing added/removed patents, score delta,
+    and a summary narrative.
+
+    Args:
+        company_name: Company name (must match both analysis records)
+        from_id: ID of the older analysis run
+        to_id: ID of the newer analysis run
+
+    Returns:
+        AnalysisDiffResponse with added/removed/changed fields
+
+    Raises:
+        404: If either analysis ID does not exist or belongs to a different company
+    """
+    db = _get_job_db()
+
+    from_rec = db.get_analysis_by_id(from_id)
+    if not from_rec or (from_rec["company_name"] or "").lower() != company_name.lower():
+        raise HTTPException(
+            status_code=404,
+            detail=f"Analysis ID {from_id} not found for company '{company_name}'",
+        )
+
+    to_rec = db.get_analysis_by_id(to_id)
+    if not to_rec or (to_rec["company_name"] or "").lower() != company_name.lower():
+        raise HTTPException(
+            status_code=404,
+            detail=f"Analysis ID {to_id} not found for company '{company_name}'",
+        )
+
+    return _compute_analysis_diff(from_rec, to_rec)
+
+
 @app.get(
     "/analyze/patent/{patent_id}",
     tags=["Analysis"],
 )
 async def analyze_single_patent(
     patent_id: str,
-    company_name: str = Query(description="Company name for analysis context"),
+    company_name: Annotated[str, Query(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$", description="Company name for analysis context")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Analyze a single patent by its publication ID.
@@ -872,6 +1255,58 @@ async def analyze_single_patent(
         raise HTTPException(status_code=404, detail=str(e))
 
 
+@app.get(
+    "/analyze/batch",
+    response_model=PaginatedAnalysisResponse,
+    tags=["Analysis"],
+)
+async def list_analysis_results(
+    company_name: Annotated[
+        str | None,
+        Query(description="Filter results by company name"),
+    ] = None,
+    limit: Annotated[int, Query(ge=1, le=200)] = 50,
+    cursor: Annotated[
+        str | None,
+        Query(description="Opaque cursor from a previous response's next_cursor field"),
+    ] = None,
+    _: UserResponse = Depends(get_current_user),
+):
+    """List stored analysis results with cursor-based pagination.
+
+    Returns past analysis results ordered by timestamp descending. Use
+    ``limit`` to control page size (default 50, max 200). The response
+    includes a ``next_cursor`` field; pass it back as the ``cursor`` query
+    parameter to fetch the next page. When ``next_cursor`` is ``null``,
+    there are no more results.
+
+    Args:
+        company_name: Optional filter by company name
+        limit: Maximum number of results to return (default 50, max 200)
+        cursor: Opaque pagination cursor from a previous response
+
+    Returns:
+        Paginated list of analysis results
+    """
+    db = _get_job_db()
+    rows = db.list_analyses(company_name=company_name, limit=limit + 1, cursor=cursor)
+
+    has_next = len(rows) > limit
+    if has_next:
+        rows = rows[:limit]
+
+    items = [AnalysisRecord(**row) for row in rows]
+
+    next_cursor = None
+    if has_next and rows:
+        last = rows[-1]
+        ts = last["timestamp"]
+        ts_str = ts.isoformat() if hasattr(ts, "isoformat") else str(ts)
+        next_cursor = f"{ts_str}|{last['id']}"
+
+    return PaginatedAnalysisResponse(items=items, next_cursor=next_cursor)
+
+
 @app.post(
     "/analyze/batch",
     response_model=BatchAnalysisResponse,
@@ -1047,7 +1482,7 @@ async def list_jobs(
         str | None,
         Query(description="Filter by status: pending, running, completed, failed"),
     ] = None,
-    limit: Annotated[int, Query(ge=1, le=100)] = 10,
+    limit: Annotated[int, Query(ge=1, le=200)] = 50,
     cursor: Annotated[
         str | None,
         Query(description="Opaque cursor from a previous response's next_cursor field"),

SPARC/auth.py

@@ -1,11 +1,13 @@
-"""JWT authentication utilities for SPARC API."""
+"""JWT and API key authentication utilities for SPARC API."""
 
 import os
+import secrets
 from datetime import datetime, timedelta, timezone
 from typing import Optional
 
+import bcrypt
 import jwt
-from fastapi import Depends, HTTPException, status
+from fastapi import Depends, HTTPException, Request, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from pydantic import BaseModel
 
@@ -32,7 +34,7 @@ def check_jwt_secret() -> None:
             "Set a secure JWT_SECRET environment variable before running in non-development environments."
         )
 
-security = HTTPBearer()
+security = HTTPBearer(auto_error=False)
 
 
 class TokenPayload(BaseModel):
@@ -178,20 +180,107 @@ def get_db_client() -> DatabaseClient:
     return _db_client
 
 
-async def get_current_user(
-    credentials: HTTPAuthorizationCredentials = Depends(security),
-) -> UserResponse:
-    """Get the current authenticated user from JWT token.
+def generate_api_key() -> str:
+    """Generate a random 32-byte hex API key.
+
+    Returns:
+        64-character hex string
+    """
+    return secrets.token_hex(32)
+
+
+def hash_api_key(key: str) -> str:
+    """Hash an API key using bcrypt.
 
     Args:
-        credentials: Bearer token from request
+        key: Plaintext API key
+
+    Returns:
+        bcrypt hash string
+    """
+    return bcrypt.hashpw(key.encode(), bcrypt.gensalt()).decode()
+
+
+def verify_api_key(key: str, key_hash: str) -> bool:
+    """Verify a plaintext API key against its bcrypt hash.
+
+    Args:
+        key: Plaintext API key
+        key_hash: Stored bcrypt hash
+
+    Returns:
+        True if key matches
+    """
+    return bcrypt.checkpw(key.encode(), key_hash.encode())
+
+
+def _authenticate_via_api_key(api_key: str) -> Optional[UserResponse]:
+    """Look up a user by raw API key.
+
+    Iterates over all stored key hashes (small table) and returns the
+    corresponding user when a match is found.
+
+    Args:
+        api_key: Plaintext API key from X-API-Key header
+
+    Returns:
+        UserResponse if valid key, None otherwise
+    """
+    db = get_db_client()
+    key_rows = db.get_all_api_key_hashes()
+
+    for row in key_rows:
+        if verify_api_key(api_key, row["key_hash"]):
+            user = db.get_user_by_id(row["user_id"])
+            if user:
+                return UserResponse(
+                    id=user["id"],
+                    email=user["email"],
+                    role=user["role"],
+                    created_at=user["created_at"],
+                )
+    return None
+
+
+async def get_current_user(
+    request: Request,
+    credentials: Optional[HTTPAuthorizationCredentials] = Depends(security),
+) -> UserResponse:
+    """Get the current authenticated user from JWT token or API key.
+
+    Supports two authentication methods:
+    1. Bearer JWT token via Authorization header
+    2. API key via X-API-Key header
+
+    Args:
+        request: The incoming request (used for X-API-Key header)
+        credentials: Optional Bearer token from request
 
     Returns:
         UserResponse with user details
 
     Raises:
-        HTTPException: If token is invalid or expired
+        HTTPException: If no valid credentials are provided
     """
+    # Try X-API-Key header first
+    api_key = request.headers.get("X-API-Key")
+    if api_key:
+        user = _authenticate_via_api_key(api_key)
+        if user:
+            return user
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Invalid API key",
+        )
+
+    # Fall back to JWT Bearer token
+    if not credentials:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Missing authentication credentials",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
     token = credentials.credentials
     payload = decode_token(token)
 

SPARC/database.py

@@ -221,6 +221,27 @@ class DatabaseClient:
                 ON alerts(company_name)
             """)
 
+            # Create API keys table for programmatic access
+            cursor.execute("""
+                CREATE TABLE IF NOT EXISTS api_keys (
+                    id SERIAL PRIMARY KEY,
+                    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+                    key_hash VARCHAR(255) NOT NULL,
+                    label VARCHAR(100),
+                    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+                )
+            """)
+
+            cursor.execute("""
+                CREATE INDEX IF NOT EXISTS idx_api_keys_user_id
+                ON api_keys(user_id)
+            """)
+
+            cursor.execute("""
+                CREATE INDEX IF NOT EXISTS idx_api_keys_key_hash
+                ON api_keys(key_hash)
+            """)
+
             self.conn.commit()
 
     @staticmethod
@@ -371,6 +392,48 @@ class DatabaseClient:
                 cursor.execute(query, params)
                 return [dict(row) for row in cursor.fetchall()]
 
+    def list_analyses(
+        self,
+        company_name: Optional[str] = None,
+        limit: int = 50,
+        cursor: Optional[str] = None,
+    ) -> List[Dict]:
+        """List analysis results with cursor-based pagination.
+
+        Args:
+            company_name: Optional filter by company name.
+            limit: Maximum number of records to return.
+            cursor: Opaque cursor (``timestamp|id``) from a previous response.
+
+        Returns:
+            List of analysis dicts ordered by timestamp descending.
+        """
+        conditions: list[str] = ["is_cached = FALSE"]
+        params: list = []
+
+        if company_name:
+            conditions.append("LOWER(company_name) = LOWER(%s)")
+            params.append(company_name)
+
+        if cursor:
+            try:
+                ts_str, cursor_id = cursor.rsplit("|", 1)
+                conditions.append("(timestamp, id) < (%s, %s)")
+                params.extend([ts_str, int(cursor_id)])
+            except (ValueError, TypeError):
+                pass  # Ignore malformed cursors; return from start
+
+        query = "SELECT id, company_name, analysis_type, model, response, timestamp FROM llm_messages"
+        if conditions:
+            query += " WHERE " + " AND ".join(conditions)
+        query += " ORDER BY timestamp DESC, id DESC LIMIT %s"
+        params.append(limit)
+
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cur:
+                cur.execute(query, params)
+                return [dict(row) for row in cur.fetchall()]
+
     def get_analytics(self, days: int = 30) -> Dict:
         """Get analytics on message usage.
 
@@ -935,3 +998,138 @@ class DatabaseClient:
                     (limit,),
                 )
                 return [dict(row) for row in cursor.fetchall()]
+
+    # Historical Analysis Diff Methods
+
+    def get_analysis_by_id(self, analysis_id: int) -> Optional[Dict]:
+        """Get a single analysis record by its ID.
+
+        Args:
+            analysis_id: The primary key of the llm_messages row.
+
+        Returns:
+            Dict with analysis fields, or None if not found.
+        """
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cursor:
+                cursor.execute(
+                    """
+                    SELECT id, company_name, analysis_type, model, response, timestamp
+                    FROM llm_messages
+                    WHERE id = %s AND is_cached = FALSE
+                    """,
+                    (analysis_id,),
+                )
+                row = cursor.fetchone()
+                return dict(row) if row else None
+
+    def list_company_analyses(
+        self, company_name: str, limit: int = 20
+    ) -> List[Dict]:
+        """List past analysis runs for a given company.
+
+        Returns records ordered by timestamp descending so callers can
+        identify which previous runs are available for diffing.
+
+        Args:
+            company_name: Company name (case-insensitive match).
+            limit: Maximum number of records.
+
+        Returns:
+            List of analysis dicts.
+        """
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cursor:
+                cursor.execute(
+                    """
+                    SELECT id, company_name, analysis_type, model, response, timestamp
+                    FROM llm_messages
+                    WHERE LOWER(company_name) = LOWER(%s) AND is_cached = FALSE
+                    ORDER BY timestamp DESC
+                    LIMIT %s
+                    """,
+                    (company_name, limit),
+                )
+                return [dict(row) for row in cursor.fetchall()]
+
+    # API Key Methods
+
+    def create_api_key(
+        self,
+        user_id: int,
+        key_hash: str,
+        label: Optional[str] = None,
+    ) -> Dict:
+        """Store a new API key hash for a user.
+
+        Args:
+            user_id: The owning user's ID
+            key_hash: bcrypt hash of the plaintext key
+            label: Optional human-readable label
+
+        Returns:
+            Dict with id, user_id, label, created_at
+        """
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cursor:
+                cursor.execute(
+                    """
+                    INSERT INTO api_keys (user_id, key_hash, label)
+                    VALUES (%s, %s, %s)
+                    RETURNING id, user_id, label, created_at
+                    """,
+                    (user_id, key_hash, label),
+                )
+                row = cursor.fetchone()
+            conn.commit()
+            return dict(row)
+
+    def list_api_keys(self, user_id: int) -> List[Dict]:
+        """List active API key metadata for a user (no secrets).
+
+        Args:
+            user_id: The user's ID
+
+        Returns:
+            List of dicts with id, label, created_at
+        """
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cursor:
+                cursor.execute(
+                    "SELECT id, label, created_at FROM api_keys WHERE user_id = %s ORDER BY created_at DESC",
+                    (user_id,),
+                )
+                return [dict(row) for row in cursor.fetchall()]
+
+    def delete_api_key(self, key_id: int, user_id: int) -> bool:
+        """Revoke an API key by ID (must belong to user).
+
+        Args:
+            key_id: The API key row ID
+            user_id: The owning user's ID
+
+        Returns:
+            True if a key was deleted
+        """
+        with self.get_conn() as conn:
+            with conn.cursor() as cursor:
+                cursor.execute(
+                    "DELETE FROM api_keys WHERE id = %s AND user_id = %s",
+                    (key_id, user_id),
+                )
+                deleted = cursor.rowcount > 0
+            conn.commit()
+            return deleted
+
+    def get_all_api_key_hashes(self) -> List[Dict]:
+        """Return all API key hashes with their associated user IDs.
+
+        Used by the auth layer to validate an incoming API key.
+
+        Returns:
+            List of dicts with key_hash, user_id
+        """
+        with self.get_conn() as conn:
+            with conn.cursor(cursor_factory=RealDictCursor) as cursor:
+                cursor.execute("SELECT key_hash, user_id FROM api_keys")
+                return [dict(row) for row in cursor.fetchall()]

SPARC/scheduler.py

@@ -2,14 +2,17 @@
 
 Uses APScheduler to periodically re-analyze tracked companies and
 detect significant changes in patent counts.
+
+The scheduler reuses the application-level pooled DatabaseClient
+(from ``SPARC.auth``) instead of creating its own connection, which
+avoids exhausting the database connection pool under load.
 """
 
 import logging
 import os
 
-from SPARC import config
 from SPARC.analyzer import CompanyAnalyzer
-from SPARC.database import DatabaseClient
+from SPARC.auth import get_db_client
 
 logger = logging.getLogger(__name__)
 
@@ -21,10 +24,13 @@ CHANGE_THRESHOLD_PERCENT = int(os.getenv("CHANGE_THRESHOLD_PERCENT", "20"))
 
 
 def run_scheduled_analysis() -> None:
-    """Re-analyze all tracked companies and check for significant changes."""
-    db = DatabaseClient(config.database_url)
-    db.connect()
-    db.initialize_schema()
+    """Re-analyze all tracked companies and check for significant changes.
+
+    Uses the shared pooled DatabaseClient from ``SPARC.auth.get_db_client()``
+    rather than creating a disposable connection, so the scheduler participates
+    in the same connection pool as the rest of the application.
+    """
+    db = get_db_client()
 
     tracked = db.list_tracked_companies()
     if not tracked:
@@ -74,7 +80,6 @@ def run_scheduled_analysis() -> None:
         except Exception as e:
             logger.error("Error analyzing tracked company %s: %s", name, e)
 
-    db.close()
     logger.info("Scheduled analysis complete")
 
 

frontend/src/App.tsx

@@ -11,7 +11,9 @@ import { Batch } from './pages/Batch';
 import { AnalyticsPage } from './pages/Analytics';
 import { About } from './pages/About';
 import { AdminUsers } from './pages/AdminUsers';
+import { AdminRateLimits } from './pages/AdminRateLimits';
 import { Compare } from './pages/Compare';
+import { HistoryDiff } from './pages/HistoryDiff';
 
 const queryClient = new QueryClient({
   defaultOptions: {
@@ -45,6 +47,7 @@ function App() {
               <Route path="/batch" element={<Batch />} />
               <Route path="/analytics" element={<AnalyticsPage />} />
               <Route path="/compare" element={<Compare />} />
+              <Route path="/history-diff" element={<HistoryDiff />} />
               <Route path="/about" element={<About />} />
 
               {/* Admin routes */}
@@ -56,6 +59,14 @@ function App() {
                   </ProtectedRoute>
                 }
               />
+              <Route
+                path="/admin/rate-limits"
+                element={
+                  <ProtectedRoute requireAdmin>
+                    <AdminRateLimits />
+                  </ProtectedRoute>
+                }
+              />
             </Route>
 
             {/* Default redirect */}

frontend/src/api/client.ts

@@ -148,8 +148,43 @@ export const analysisApi = {
     const response = await api.get<JobStatus[]>(`/jobs?${params}`);
     return response.data;
   },
+
+  getCompanyHistory: async (companyName: string, limit = 20): Promise<AnalysisHistoryItem[]> => {
+    const response = await api.get<AnalysisHistoryItem[]>(
+      `/analyze/${encodeURIComponent(companyName)}/history?limit=${limit}`
+    );
+    return response.data;
+  },
+
+  diffAnalyses: async (companyName: string, fromId: number, toId: number): Promise<AnalysisDiff> => {
+    const response = await api.get<AnalysisDiff>(
+      `/analyze/${encodeURIComponent(companyName)}/diff?from=${fromId}&to=${toId}`
+    );
+    return response.data;
+  },
 };
 
+// Analysis diff types
+export interface AnalysisHistoryItem {
+  id: number;
+  analysis_type: string | null;
+  model: string | null;
+  timestamp: string;
+}
+
+export interface AnalysisDiff {
+  company_name: string;
+  from_id: number;
+  to_id: number;
+  from_timestamp: string;
+  to_timestamp: string;
+  patent_count_delta: number;
+  added_patents: string[];
+  removed_patents: string[];
+  changed_fields: Record<string, { from: string | null; to: string | null }>;
+  summary: string;
+}
+
 // Export API
 export const exportApi = {
   exportCsv: async (companyName: string): Promise<void> => {
@@ -201,6 +236,32 @@ export const analyticsApi = {
   },
 };
 
+// Rate limit types
+export interface RateLimitIpEntry {
+  ip: string;
+  total: number;
+  rejected: number;
+}
+
+export interface RateLimitEndpointStats {
+  endpoint: string;
+  limit: string;
+  total_requests: number;
+  rejected_requests: number;
+  by_ip: RateLimitIpEntry[];
+}
+
+export interface ThrottledBucket {
+  timestamp: string;
+  count: number;
+}
+
+export interface RateLimitStatsResponse {
+  rate_limits: RateLimitEndpointStats[];
+  throttled_24h: number;
+  throttled_over_time: ThrottledBucket[];
+}
+
 // Admin API
 export const adminApi = {
   listUsers: async (limit = 100, offset = 0): Promise<User[]> => {
@@ -216,6 +277,11 @@ export const adminApi = {
   deleteUser: async (userId: number): Promise<void> => {
     await api.delete(`/admin/users/${userId}`);
   },
+
+  getRateLimits: async (): Promise<RateLimitStatsResponse> => {
+    const response = await api.get<RateLimitStatsResponse>('/admin/rate-limits');
+    return response.data;
+  },
 };
 
 export default api;

frontend/src/components/Layout.tsx

@@ -1,7 +1,7 @@
 import { Outlet, NavLink, useNavigate } from 'react-router-dom';
 import { useAuth } from '../context/AuthContext';
 import { useTheme } from '../context/ThemeContext';
-import { Search, Layers, BarChart3, Info, Users, LogOut, GitCompareArrows, Sun, Moon } from 'lucide-react';
+import { Search, Layers, BarChart3, Info, Users, LogOut, GitCompareArrows, Sun, Moon, History, ShieldAlert } from 'lucide-react';
 
 export function Layout() {
   const { user, isAdmin, logout } = useAuth();
@@ -18,11 +18,13 @@ export function Layout() {
     { to: '/batch', icon: Layers, label: 'Batch' },
     { to: '/analytics', icon: BarChart3, label: 'Analytics' },
     { to: '/compare', icon: GitCompareArrows, label: 'Compare' },
+    { to: '/history-diff', icon: History, label: 'Diff' },
     { to: '/about', icon: Info, label: 'About' },
   ];
 
   if (isAdmin) {
     navItems.push({ to: '/admin/users', icon: Users, label: 'Users' });
+    navItems.push({ to: '/admin/rate-limits', icon: ShieldAlert, label: 'Rate Limits' });
   }
 
   return (

frontend/src/pages/AdminRateLimits.tsx

@@ -0,0 +1,240 @@
+import { useState } from 'react';
+import { useQuery } from '@tanstack/react-query';
+import { adminApi } from '../api/client';
+import type { RateLimitStatsResponse } from '../api/client';
+import { ShieldAlert, Activity, AlertCircle, RefreshCw, Clock } from 'lucide-react';
+
+const REFRESH_OPTIONS = [
+  { label: '15s', value: 15_000 },
+  { label: '30s', value: 30_000 },
+  { label: '1m', value: 60_000 },
+  { label: 'Off', value: 0 },
+];
+
+export function AdminRateLimits() {
+  const [refreshInterval, setRefreshInterval] = useState(30_000);
+
+  const { data, isLoading, isError, dataUpdatedAt } = useQuery<RateLimitStatsResponse>({
+    queryKey: ['admin-rate-limits'],
+    queryFn: () => adminApi.getRateLimits(),
+    refetchInterval: refreshInterval || false,
+  });
+
+  if (isLoading) {
+    return (
+      <div className="flex items-center justify-center min-h-[400px]">
+        <div className="animate-spin rounded-full h-12 w-12 border-t-2 border-b-2 border-primary"></div>
+      </div>
+    );
+  }
+
+  if (isError) {
+    return (
+      <div className="flex items-center gap-2 bg-error/10 border border-error/20 text-error rounded-xl px-4 py-3">
+        <AlertCircle size={18} />
+        <span>Failed to load rate limit statistics.</span>
+      </div>
+    );
+  }
+
+  const maxThrottledCount = data?.throttled_over_time?.length
+    ? Math.max(...data.throttled_over_time.map((b) => b.count))
+    : 0;
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div className="flex items-center justify-between flex-wrap gap-4">
+        <div>
+          <h2 className="text-xl font-semibold text-text-primary border-b-2 border-primary/30 pb-2 mb-2">
+            Rate Limiting Dashboard
+          </h2>
+          <p className="text-text-secondary">Monitor API rate limits and throttled requests.</p>
+        </div>
+        <div className="flex items-center gap-3">
+          {/* Last updated */}
+          {dataUpdatedAt > 0 && (
+            <span className="text-xs text-text-secondary flex items-center gap-1">
+              <Clock size={12} />
+              Updated {new Date(dataUpdatedAt).toLocaleTimeString()}
+            </span>
+          )}
+          {/* Refresh interval selector */}
+          <div className="flex items-center gap-1 bg-bg-card/60 border border-primary/15 rounded-xl p-1">
+            <RefreshCw size={14} className="text-text-secondary ml-2" />
+            {REFRESH_OPTIONS.map((opt) => (
+              <button
+                key={opt.value}
+                onClick={() => setRefreshInterval(opt.value)}
+                className={`px-3 py-1 rounded-lg text-xs font-medium transition-all ${
+                  refreshInterval === opt.value
+                    ? 'bg-primary text-white'
+                    : 'text-text-secondary hover:text-text-primary hover:bg-bg-card-hover'
+                }`}
+              >
+                {opt.label}
+              </button>
+            ))}
+          </div>
+        </div>
+      </div>
+
+      {/* Summary cards */}
+      <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
+        <div className="bg-bg-card/60 border border-primary/15 rounded-2xl p-5">
+          <div className="flex items-center gap-2 mb-2">
+            <Activity size={18} className="text-primary" />
+            <span className="text-sm font-semibold text-text-secondary uppercase tracking-wider">
+              Total Requests
+            </span>
+          </div>
+          <div className="text-3xl font-bold text-text-primary">
+            {data?.rate_limits.reduce((sum, rl) => sum + rl.total_requests, 0) ?? 0}
+          </div>
+        </div>
+        <div className="bg-bg-card/60 border border-error/15 rounded-2xl p-5">
+          <div className="flex items-center gap-2 mb-2">
+            <ShieldAlert size={18} className="text-error" />
+            <span className="text-sm font-semibold text-text-secondary uppercase tracking-wider">
+              Throttled (24h)
+            </span>
+          </div>
+          <div className="text-3xl font-bold text-error">
+            {data?.throttled_24h ?? 0}
+          </div>
+        </div>
+        <div className="bg-bg-card/60 border border-secondary/15 rounded-2xl p-5">
+          <div className="flex items-center gap-2 mb-2">
+            <ShieldAlert size={18} className="text-secondary" />
+            <span className="text-sm font-semibold text-text-secondary uppercase tracking-wider">
+              Rate-Limited Endpoints
+            </span>
+          </div>
+          <div className="text-3xl font-bold text-text-primary">
+            {data?.rate_limits.length ?? 0}
+          </div>
+        </div>
+      </div>
+
+      {/* Throttled over time chart (simple bar chart) */}
+      {data?.throttled_over_time && data.throttled_over_time.length > 0 && (
+        <div className="bg-bg-card/60 border border-primary/15 rounded-2xl p-5">
+          <h3 className="text-sm font-semibold text-text-secondary uppercase tracking-wider mb-4">
+            Throttled Requests Over Time (Last 24h)
+          </h3>
+          <div className="flex items-end gap-1 h-32">
+            {data.throttled_over_time.map((bucket) => {
+              const height = maxThrottledCount > 0 ? (bucket.count / maxThrottledCount) * 100 : 0;
+              const hour = new Date(bucket.timestamp).getHours();
+              return (
+                <div key={bucket.timestamp} className="flex-1 flex flex-col items-center gap-1">
+                  <span className="text-xs text-text-secondary">{bucket.count}</span>
+                  <div
+                    className="w-full bg-error/70 rounded-t-sm min-h-[2px] transition-all"
+                    style={{ height: `${Math.max(height, 2)}%` }}
+                    title={`${bucket.timestamp}: ${bucket.count} throttled`}
+                  />
+                  <span className="text-[10px] text-text-secondary">{hour}:00</span>
+                </div>
+              );
+            })}
+          </div>
+        </div>
+      )}
+
+      {/* Per-endpoint table */}
+      <div className="bg-bg-card/60 border border-primary/15 rounded-2xl overflow-hidden">
+        <div className="overflow-x-auto">
+          <table className="w-full">
+            <thead>
+              <tr className="border-b border-primary/10">
+                <th className="text-left px-6 py-4 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                  Endpoint
+                </th>
+                <th className="text-left px-6 py-4 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                  Limit
+                </th>
+                <th className="text-right px-6 py-4 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                  Total Requests
+                </th>
+                <th className="text-right px-6 py-4 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                  Rejected
+                </th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-primary/10">
+              {data?.rate_limits.map((rl) => (
+                <tr key={rl.endpoint} className="hover:bg-bg-card-hover/50 transition-colors">
+                  <td className="px-6 py-4 font-mono text-sm text-text-primary">{rl.endpoint}</td>
+                  <td className="px-6 py-4">
+                    <span className="inline-flex px-2 py-0.5 rounded-full text-xs font-medium bg-primary/10 text-primary border border-primary/20">
+                      {rl.limit}
+                    </span>
+                  </td>
+                  <td className="px-6 py-4 text-right text-text-primary font-semibold">
+                    {rl.total_requests}
+                  </td>
+                  <td className="px-6 py-4 text-right">
+                    <span className={rl.rejected_requests > 0 ? 'text-error font-semibold' : 'text-text-secondary'}>
+                      {rl.rejected_requests}
+                    </span>
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      </div>
+
+      {/* Per-IP breakdown */}
+      {data?.rate_limits.some((rl) => rl.by_ip.length > 0) && (
+        <div className="bg-bg-card/60 border border-primary/15 rounded-2xl overflow-hidden">
+          <div className="px-6 py-4 border-b border-primary/10">
+            <h3 className="text-sm font-semibold text-text-secondary uppercase tracking-wider">
+              Per-IP Breakdown
+            </h3>
+          </div>
+          <div className="overflow-x-auto">
+            <table className="w-full">
+              <thead>
+                <tr className="border-b border-primary/10">
+                  <th className="text-left px-6 py-3 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                    Endpoint
+                  </th>
+                  <th className="text-left px-6 py-3 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                    IP Address
+                  </th>
+                  <th className="text-right px-6 py-3 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                    Total
+                  </th>
+                  <th className="text-right px-6 py-3 text-sm font-semibold text-text-secondary uppercase tracking-wider">
+                    Rejected
+                  </th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-primary/10">
+                {data.rate_limits.flatMap((rl) =>
+                  rl.by_ip.map((ipEntry) => (
+                    <tr
+                      key={`${rl.endpoint}-${ipEntry.ip}`}
+                      className="hover:bg-bg-card-hover/50 transition-colors"
+                    >
+                      <td className="px-6 py-3 font-mono text-sm text-text-primary">{rl.endpoint}</td>
+                      <td className="px-6 py-3 font-mono text-sm text-text-secondary">{ipEntry.ip}</td>
+                      <td className="px-6 py-3 text-right text-text-primary">{ipEntry.total}</td>
+                      <td className="px-6 py-3 text-right">
+                        <span className={ipEntry.rejected > 0 ? 'text-error font-semibold' : 'text-text-secondary'}>
+                          {ipEntry.rejected}
+                        </span>
+                      </td>
+                    </tr>
+                  ))
+                )}
+              </tbody>
+            </table>
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

frontend/src/pages/Analysis.tsx

@@ -1,10 +1,12 @@
 import { useState } from 'react';
+import { useNavigate } from 'react-router-dom';
 import { useMutation, useQuery } from '@tanstack/react-query';
 import { analysisApi, exportApi } from '../api/client';
-import { Search, CheckCircle, AlertCircle, Clock, FileText, Download, ChevronDown } from 'lucide-react';
+import { Search, CheckCircle, AlertCircle, Clock, FileText, Download, ChevronDown, History } from 'lucide-react';
 import type { CompanyAnalysis } from '../types';
 
 export function Analysis() {
+  const navigate = useNavigate();
   const [companyName, setCompanyName] = useState('');
   const [selectedModel, setSelectedModel] = useState('');
   const [result, setResult] = useState<CompanyAnalysis | null>(null);
@@ -157,6 +159,13 @@ export function Analysis() {
                     <FileText size={14} />
                     Export PDF
                   </button>
+                  <button
+                    onClick={() => navigate(`/history-diff?company=${encodeURIComponent(result.company_name)}`)}
+                    className="flex items-center gap-2 text-sm bg-secondary/20 hover:bg-secondary/30 text-secondary font-medium px-3 py-1.5 rounded-lg transition-colors"
+                  >
+                    <History size={14} />
+                    Compare with previous
+                  </button>
                 </div>
               </div>
               <div className="prose dark:prose-invert max-w-none">

frontend/src/pages/HistoryDiff.tsx

@@ -0,0 +1,249 @@
+import { useState } from 'react';
+import { useSearchParams } from 'react-router-dom';
+import { useQuery } from '@tanstack/react-query';
+import { analysisApi } from '../api/client';
+import type { AnalysisHistoryItem, AnalysisDiff } from '../api/client';
+import { History, ArrowRight, Plus, Minus, AlertCircle, Search } from 'lucide-react';
+
+export function HistoryDiff() {
+  const [searchParams, setSearchParams] = useSearchParams();
+  const [companyInput, setCompanyInput] = useState(searchParams.get('company') || '');
+
+  const company = searchParams.get('company') || '';
+  const fromId = searchParams.get('from');
+  const toId = searchParams.get('to');
+
+  // Fetch history when a company is selected
+  const historyQuery = useQuery({
+    queryKey: ['history', company],
+    queryFn: () => analysisApi.getCompanyHistory(company),
+    enabled: !!company,
+  });
+
+  // Fetch diff when both IDs are selected
+  const diffQuery = useQuery<AnalysisDiff>({
+    queryKey: ['diff', company, fromId, toId],
+    queryFn: () => analysisApi.diffAnalyses(company, Number(fromId), Number(toId)),
+    enabled: !!company && !!fromId && !!toId,
+  });
+
+  const handleSearch = (e: React.FormEvent) => {
+    e.preventDefault();
+    const name = companyInput.trim();
+    if (name) {
+      setSearchParams({ company: name });
+    }
+  };
+
+  const handleSelectRuns = (from: number, to: number) => {
+    setSearchParams({ company, from: String(from), to: String(to) });
+  };
+
+  const history: AnalysisHistoryItem[] = historyQuery.data || [];
+
+  return (
+    <div className="space-y-6">
+      {/* Header */}
+      <div>
+        <h2 className="text-xl font-semibold text-text-primary border-b-2 border-primary/30 pb-2 mb-2">
+          Historical Analysis Diff
+        </h2>
+        <p className="text-text-secondary">
+          Compare analysis runs for the same company to see what changed between them.
+        </p>
+      </div>
+
+      {/* Company Search */}
+      <form onSubmit={handleSearch} className="flex gap-4">
+        <div className="flex-1 relative">
+          <Search className="absolute left-4 top-1/2 -translate-y-1/2 text-text-secondary" size={18} />
+          <input
+            type="text"
+            value={companyInput}
+            onChange={(e) => setCompanyInput(e.target.value)}
+            placeholder="Enter company name (e.g., nvidia)"
+            className="w-full bg-bg-card/80 border border-primary/30 rounded-xl pl-12 pr-4 py-3 text-text-primary placeholder-text-secondary/50 focus:outline-none focus:border-primary focus:ring-2 focus:ring-primary/20 transition-all"
+          />
+        </div>
+        <button
+          type="submit"
+          disabled={!companyInput.trim()}
+          className="bg-gradient-to-r from-primary to-primary-dark text-white font-semibold py-3 px-6 rounded-xl hover:shadow-lg hover:shadow-primary/30 transition-all disabled:opacity-50 disabled:cursor-not-allowed flex items-center gap-2"
+        >
+          <History size={18} />
+          Load History
+        </button>
+      </form>
+
+      {/* History list */}
+      {company && historyQuery.isLoading && (
+        <div className="text-text-secondary animate-pulse">Loading analysis history...</div>
+      )}
+
+      {company && historyQuery.isError && (
+        <div className="flex items-center gap-2 bg-error/10 border border-error/20 text-error rounded-xl px-4 py-3">
+          <AlertCircle size={18} />
+          <span>Failed to load history. Check the company name and try again.</span>
+        </div>
+      )}
+
+      {company && history.length === 0 && !historyQuery.isLoading && (
+        <div className="text-text-secondary">No analysis history found for "{company}".</div>
+      )}
+
+      {history.length >= 2 && (
+        <div className="bg-bg-card/60 backdrop-blur-lg border border-primary/15 rounded-2xl p-6">
+          <h3 className="text-lg font-semibold text-text-primary border-b-2 border-primary/30 pb-2 mb-4">
+            Select Two Runs to Compare
+          </h3>
+          <div className="space-y-2">
+            {history.map((item, idx) => {
+              const next = history[idx + 1];
+              if (!next) return null;
+              const isSelected =
+                fromId === String(next.id) && toId === String(item.id);
+              return (
+                <button
+                  key={item.id}
+                  onClick={() => handleSelectRuns(next.id, item.id)}
+                  className={`w-full text-left flex items-center gap-3 px-4 py-3 rounded-xl border transition-all ${
+                    isSelected
+                      ? 'border-primary bg-primary/10'
+                      : 'border-primary/15 hover:border-primary/40 hover:bg-primary/5'
+                  }`}
+                >
+                  <span className="text-sm text-text-secondary font-mono">
+                    #{next.id}
+                  </span>
+                  <span className="text-xs text-text-secondary">
+                    {new Date(next.timestamp).toLocaleString()}
+                  </span>
+                  <ArrowRight size={14} className="text-primary" />
+                  <span className="text-sm text-text-secondary font-mono">
+                    #{item.id}
+                  </span>
+                  <span className="text-xs text-text-secondary">
+                    {new Date(item.timestamp).toLocaleString()}
+                  </span>
+                  {item.model && (
+                    <span className="ml-auto text-xs bg-primary/20 text-primary px-2 py-0.5 rounded">
+                      {item.model}
+                    </span>
+                  )}
+                </button>
+              );
+            })}
+          </div>
+        </div>
+      )}
+
+      {/* Diff Results */}
+      {diffQuery.isLoading && (
+        <div className="text-text-secondary animate-pulse">Computing diff...</div>
+      )}
+
+      {diffQuery.isError && (
+        <div className="flex items-center gap-2 bg-error/10 border border-error/20 text-error rounded-xl px-4 py-3">
+          <AlertCircle size={18} />
+          <span>Failed to compute diff. One or both analysis IDs may not exist.</span>
+        </div>
+      )}
+
+      {diffQuery.data && <DiffView diff={diffQuery.data} />}
+    </div>
+  );
+}
+
+function DiffView({ diff }: { diff: AnalysisDiff }) {
+  return (
+    <div className="bg-bg-card/60 backdrop-blur-lg border border-primary/15 rounded-2xl p-6 space-y-6">
+      <h3 className="text-lg font-semibold text-text-primary border-b-2 border-primary/30 pb-2">
+        Diff: #{diff.from_id} &rarr; #{diff.to_id}
+      </h3>
+
+      {/* Summary */}
+      <div className="bg-primary/5 border border-primary/20 rounded-xl p-4">
+        <div className="text-sm font-medium text-text-primary">{diff.summary}</div>
+        <div className="flex items-center gap-4 mt-2 text-xs text-text-secondary">
+          <span>{new Date(diff.from_timestamp).toLocaleString()}</span>
+          <ArrowRight size={12} />
+          <span>{new Date(diff.to_timestamp).toLocaleString()}</span>
+        </div>
+      </div>
+
+      {/* Patent count delta */}
+      <div className="flex items-center gap-3">
+        <span className="text-sm text-text-secondary">Patent mention delta:</span>
+        <span
+          className={`text-lg font-bold ${
+            diff.patent_count_delta > 0
+              ? 'text-success'
+              : diff.patent_count_delta < 0
+              ? 'text-error'
+              : 'text-text-secondary'
+          }`}
+        >
+          {diff.patent_count_delta > 0 ? '+' : ''}
+          {diff.patent_count_delta}
+        </span>
+      </div>
+
+      {/* Added patents */}
+      {diff.added_patents.length > 0 && (
+        <div>
+          <h4 className="text-sm font-semibold text-success flex items-center gap-1 mb-2">
+            <Plus size={14} />
+            New Patents ({diff.added_patents.length})
+          </h4>
+          <div className="flex flex-wrap gap-2">
+            {diff.added_patents.map((p) => (
+              <span
+                key={p}
+                className="text-xs bg-success/10 border border-success/20 text-success px-2 py-1 rounded font-mono"
+              >
+                {p}
+              </span>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Removed patents */}
+      {diff.removed_patents.length > 0 && (
+        <div>
+          <h4 className="text-sm font-semibold text-error flex items-center gap-1 mb-2">
+            <Minus size={14} />
+            Removed Patents ({diff.removed_patents.length})
+          </h4>
+          <div className="flex flex-wrap gap-2">
+            {diff.removed_patents.map((p) => (
+              <span
+                key={p}
+                className="text-xs bg-error/10 border border-error/20 text-error px-2 py-1 rounded font-mono"
+              >
+                {p}
+              </span>
+            ))}
+          </div>
+        </div>
+      )}
+
+      {/* Changed fields */}
+      {Object.keys(diff.changed_fields).length > 0 && (
+        <div>
+          <h4 className="text-sm font-semibold text-text-primary mb-2">Changed Fields</h4>
+          <div className="space-y-1">
+            {Object.entries(diff.changed_fields).map(([field, vals]) => (
+              <div key={field} className="flex items-center gap-2 text-sm">
+                <span className="text-text-secondary font-mono">{field}:</span>
+                <span className="text-error line-through">{vals.from || 'null'}</span>
+                <ArrowRight size={12} className="text-text-secondary" />
+                <span className="text-success">{vals.to || 'null'}</span>
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+    </div>
+  );
+}

tests/test_analysis_diff.py

@@ -0,0 +1,244 @@
+"""Tests for historical analysis diff endpoint."""
+
+from datetime import datetime
+from unittest.mock import MagicMock, patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import AnalysisDiffResponse, _compute_analysis_diff, _extract_patent_ids, app
+from SPARC.auth import UserResponse, get_current_user
+
+
+# ---------- helpers ----------
+
+def _mock_user():
+    """Return a fake authenticated user for dependency override."""
+    return UserResponse(
+        id=1,
+        email="test@example.com",
+        role="user",
+        created_at=datetime(2025, 1, 1),
+    )
+
+
+@pytest.fixture
+def auth_client():
+    """TestClient with auth dependency overridden."""
+    app.dependency_overrides[get_current_user] = _mock_user
+    client = TestClient(app, raise_server_exceptions=False)
+    yield client
+    app.dependency_overrides.clear()
+
+
+# ---------- unit tests for helpers ----------
+
+class TestExtractPatentIds:
+    """Test _extract_patent_ids utility."""
+
+    def test_extracts_standard_ids(self):
+        text = "Patent US-12345678-B2 covers the device. Also see US-9876543-A1."
+        ids = _extract_patent_ids(text)
+        assert "US-12345678-B2" in ids
+        assert "US-9876543-A1" in ids
+
+    def test_empty_text(self):
+        assert _extract_patent_ids("") == set()
+        assert _extract_patent_ids(None) == set()  # type: ignore[arg-type]
+
+
+class TestComputeAnalysisDiff:
+    """Test _compute_analysis_diff logic."""
+
+    def test_identical_analyses(self):
+        rec = {
+            "id": 1,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "Patent US-12345678-B2 is notable.",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        diff = _compute_analysis_diff(rec, dict(rec, id=2, timestamp=datetime(2025, 5, 2)))
+        assert diff.patent_count_delta == 0
+        assert diff.added_patents == []
+        assert diff.removed_patents == []
+
+    def test_added_and_removed_patents(self):
+        from_rec = {
+            "id": 1,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "Patent US-12345678-B2 and US-11111111-A1.",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        to_rec = {
+            "id": 2,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "Patent US-12345678-B2 and US-99999999-B1.",
+            "timestamp": datetime(2025, 5, 2),
+        }
+        diff = _compute_analysis_diff(from_rec, to_rec)
+        assert "US-99999999-B1" in diff.added_patents
+        assert "US-11111111-A1" in diff.removed_patents
+        assert diff.patent_count_delta == 0  # one added, one removed
+
+    def test_model_change_detected(self):
+        from_rec = {
+            "id": 1,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        to_rec = {
+            "id": 2,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "anthropic/claude-3.5-sonnet",
+            "response": "",
+            "timestamp": datetime(2025, 5, 2),
+        }
+        diff = _compute_analysis_diff(from_rec, to_rec)
+        assert "model" in diff.changed_fields
+        assert diff.changed_fields["model"]["from"] == "openai/gpt-4o"
+        assert diff.changed_fields["model"]["to"] == "anthropic/claude-3.5-sonnet"
+
+
+# ---------- API endpoint tests ----------
+
+class TestDiffEndpoint:
+    """Test GET /analyze/{company_name}/diff."""
+
+    @patch("SPARC.api._get_job_db")
+    def test_happy_path(self, mock_get_db, auth_client):
+        """Diff returns structured response when both IDs exist."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+
+        from_rec = {
+            "id": 10,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "Patent US-12345678-B2 found.",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        to_rec = {
+            "id": 20,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "Patent US-12345678-B2 and US-99999999-A1 found.",
+            "timestamp": datetime(2025, 5, 10),
+        }
+        db.get_analysis_by_id.side_effect = lambda aid: from_rec if aid == 10 else to_rec
+
+        response = auth_client.get("/analyze/nvidia/diff?from=10&to=20")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["company_name"] == "nvidia"
+        assert data["from_id"] == 10
+        assert data["to_id"] == 20
+        assert "US-99999999-A1" in data["added_patents"]
+        assert data["patent_count_delta"] == 1
+
+    @patch("SPARC.api._get_job_db")
+    def test_from_id_not_found(self, mock_get_db, auth_client):
+        """Returns 404 when 'from' analysis ID doesn't exist."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+        db.get_analysis_by_id.return_value = None
+
+        response = auth_client.get("/analyze/nvidia/diff?from=999&to=1000")
+        assert response.status_code == 404
+        assert "999" in response.json()["detail"]
+
+    @patch("SPARC.api._get_job_db")
+    def test_to_id_not_found(self, mock_get_db, auth_client):
+        """Returns 404 when 'to' analysis ID doesn't exist."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+
+        from_rec = {
+            "id": 10,
+            "company_name": "nvidia",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        db.get_analysis_by_id.side_effect = lambda aid: from_rec if aid == 10 else None
+
+        response = auth_client.get("/analyze/nvidia/diff?from=10&to=999")
+        assert response.status_code == 404
+        assert "999" in response.json()["detail"]
+
+    @patch("SPARC.api._get_job_db")
+    def test_company_mismatch(self, mock_get_db, auth_client):
+        """Returns 404 when analysis belongs to a different company."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+
+        rec = {
+            "id": 10,
+            "company_name": "intel",
+            "analysis_type": "portfolio",
+            "model": "openai/gpt-4o",
+            "response": "",
+            "timestamp": datetime(2025, 5, 1),
+        }
+        db.get_analysis_by_id.return_value = rec
+
+        response = auth_client.get("/analyze/nvidia/diff?from=10&to=20")
+        assert response.status_code == 404
+
+
+class TestHistoryEndpoint:
+    """Test GET /analyze/{company_name}/history."""
+
+    @patch("SPARC.api._get_job_db")
+    def test_returns_history_list(self, mock_get_db, auth_client):
+        """History endpoint returns list of past analysis runs."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+        db.list_company_analyses.return_value = [
+            {
+                "id": 20,
+                "company_name": "nvidia",
+                "analysis_type": "portfolio",
+                "model": "openai/gpt-4o",
+                "response": "...",
+                "timestamp": datetime(2025, 5, 10),
+            },
+            {
+                "id": 10,
+                "company_name": "nvidia",
+                "analysis_type": "portfolio",
+                "model": "openai/gpt-4o",
+                "response": "...",
+                "timestamp": datetime(2025, 5, 1),
+            },
+        ]
+
+        response = auth_client.get("/analyze/nvidia/history")
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data) == 2
+        assert data[0]["id"] == 20
+        assert data[1]["id"] == 10
+
+    @patch("SPARC.api._get_job_db")
+    def test_empty_history(self, mock_get_db, auth_client):
+        """History endpoint returns empty list when no analyses exist."""
+        db = MagicMock()
+        mock_get_db.return_value = db
+        db.list_company_analyses.return_value = []
+
+        response = auth_client.get("/analyze/nvidia/history")
+        assert response.status_code == 200
+        assert response.json() == []

tests/test_analyze_single_patent.py

@@ -0,0 +1,211 @@
+"""Tests for analyze_single_patent auto-download path.
+
+Covers issue #1661:
+- PDF exists on disk: direct analysis (happy path)
+- PDF not on disk, cached link exists: auto-download and analyze
+- PDF not on disk, no cached link: FileNotFoundError
+- Analysis failure after PDF found: graceful error message
+- Model override parameter passthrough
+"""
+
+import os
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from SPARC.analyzer import CompanyAnalyzer
+from SPARC.types import Patent
+
+
+@pytest.fixture(autouse=True)
+def mock_db(mocker):
+    """Mock DatabaseClient so no real DB is needed."""
+    mock_db_cls = mocker.patch("SPARC.analyzer.DatabaseClient")
+    mock_db_instance = MagicMock()
+    mock_db_instance.get_cached_patent.return_value = None
+    mock_db_instance.get_cached_serp_query.return_value = None
+    mock_db_cls.return_value = mock_db_instance
+    return mock_db_instance
+
+
+@pytest.fixture
+def analyzer(mocker, mock_db):
+    """Create a CompanyAnalyzer with mocked LLM and DB."""
+    mocker.patch("SPARC.analyzer.LLMAnalyzer")
+    return CompanyAnalyzer(openrouter_api_key="test-key")
+
+
+class TestAnalyzeSinglePatentAutoDownload:
+    """Test the auto-download logic in analyze_single_patent."""
+
+    def test_pdf_on_disk_analyzed_directly(self, analyzer, mocker, tmp_path):
+        """When PDF exists on disk, it is analyzed directly without download."""
+        patent_id = "US-11234567-B2"
+
+        # Create the patents dir and PDF file
+        patents_dir = tmp_path / "patents"
+        patents_dir.mkdir()
+        pdf_path = patents_dir / f"{patent_id}.pdf"
+        pdf_path.write_bytes(b"fake PDF content")
+
+        mock_parse = mocker.patch("SPARC.analyzer.SERP.parse_patent_pdf")
+        mock_minimize = mocker.patch("SPARC.analyzer.SERP.minimize_patent_for_llm")
+        mock_parse.return_value = {"abstract": "test", "claims": "test claims"}
+        mock_minimize.return_value = "minimized content"
+        analyzer.llm_analyzer.analyze_patent_content.return_value = "Good patent."
+
+        # Change cwd so patents/{patent_id}.pdf resolves to our tmp_path
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            result = analyzer.analyze_single_patent(patent_id, "TestCo")
+        finally:
+            os.chdir(original_cwd)
+
+        assert result == "Good patent."
+        # DB cache should not have been queried since file existed
+        analyzer.db.get_cached_patent.assert_not_called()
+
+    def test_auto_download_from_cached_link(self, analyzer, mocker, tmp_path):
+        """When PDF is not on disk but link is cached, auto-download occurs."""
+        patent_id = "US-99887766-A1"
+
+        # No patents dir exists (PDF not on disk)
+        mock_save = mocker.patch("SPARC.analyzer.SERP.save_patents")
+        downloaded_patent = Patent(patent_id=patent_id, pdf_link="https://example.com/patent.pdf")
+        downloaded_patent.pdf_path = f"patents/{patent_id}.pdf"
+        mock_save.return_value = downloaded_patent
+
+        # Cached patent has a PDF link
+        analyzer.db.get_cached_patent.return_value = {
+            "patent_id": patent_id,
+            "pdf_link": "https://example.com/patent.pdf",
+        }
+
+        # Mock the rest of the analysis pipeline
+        mock_parse = mocker.patch("SPARC.analyzer.SERP.parse_patent_pdf")
+        mock_minimize = mocker.patch("SPARC.analyzer.SERP.minimize_patent_for_llm")
+        mock_parse.return_value = {"abstract": "test abstract"}
+        mock_minimize.return_value = "minimized content"
+        analyzer.llm_analyzer.analyze_patent_content.return_value = "Strong innovation."
+
+        # Change cwd so patents/{patent_id}.pdf does NOT exist
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            result = analyzer.analyze_single_patent(patent_id, "DownloadCo")
+        finally:
+            os.chdir(original_cwd)
+
+        assert result == "Strong innovation."
+        analyzer.db.get_cached_patent.assert_called_once_with(patent_id)
+        mock_save.assert_called_once()
+        # Verify the Patent passed to save_patents has the correct ID and link
+        saved_patent = mock_save.call_args[0][0]
+        assert saved_patent.patent_id == patent_id
+        assert saved_patent.pdf_link == "https://example.com/patent.pdf"
+
+    def test_no_cached_link_raises_file_not_found(self, analyzer, mocker, tmp_path):
+        """When PDF is not on disk and no cached link, FileNotFoundError raised."""
+        patent_id = "US-00000000-X1"
+
+        analyzer.db.get_cached_patent.return_value = None
+
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            with pytest.raises(FileNotFoundError, match="no download link is cached"):
+                analyzer.analyze_single_patent(patent_id, "MissingCo")
+        finally:
+            os.chdir(original_cwd)
+
+    def test_cached_patent_without_pdf_link_raises(self, analyzer, mocker, tmp_path):
+        """When cached patent exists but has no pdf_link, FileNotFoundError raised."""
+        patent_id = "US-11111111-B1"
+
+        analyzer.db.get_cached_patent.return_value = {
+            "patent_id": patent_id,
+            "pdf_link": None,
+        }
+
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            with pytest.raises(FileNotFoundError, match="no download link is cached"):
+                analyzer.analyze_single_patent(patent_id, "NoPDFCo")
+        finally:
+            os.chdir(original_cwd)
+
+    def test_analysis_exception_returns_error_message(self, analyzer, mocker, tmp_path):
+        """When analysis pipeline fails, returns error string instead of raising."""
+        patent_id = "US-22222222-A2"
+
+        # Create the PDF on disk so it skips download
+        patents_dir = tmp_path / "patents"
+        patents_dir.mkdir()
+        (patents_dir / f"{patent_id}.pdf").write_bytes(b"fake PDF")
+
+        # Parse fails
+        mocker.patch(
+            "SPARC.analyzer.SERP.parse_patent_pdf",
+            side_effect=ValueError("Corrupt PDF"),
+        )
+
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            result = analyzer.analyze_single_patent(patent_id, "ErrorCo")
+        finally:
+            os.chdir(original_cwd)
+
+        assert "Failed to analyze patent" in result
+        assert "Corrupt PDF" in result
+
+    def test_model_override_passed_to_llm(self, analyzer, mocker, tmp_path):
+        """The model parameter is forwarded to the LLM analyzer."""
+        patent_id = "US-33333333-B2"
+
+        patents_dir = tmp_path / "patents"
+        patents_dir.mkdir()
+        (patents_dir / f"{patent_id}.pdf").write_bytes(b"fake PDF")
+
+        mocker.patch("SPARC.analyzer.SERP.parse_patent_pdf", return_value={"abstract": "test"})
+        mocker.patch("SPARC.analyzer.SERP.minimize_patent_for_llm", return_value="content")
+        analyzer.llm_analyzer.analyze_patent_content.return_value = "Analysis result."
+
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            result = analyzer.analyze_single_patent(
+                patent_id, "ModelCo", model="openai/gpt-4o"
+            )
+        finally:
+            os.chdir(original_cwd)
+
+        assert result == "Analysis result."
+        analyzer.llm_analyzer.analyze_patent_content.assert_called_once_with(
+            patent_content="content",
+            company_name="ModelCo",
+            model="openai/gpt-4o",
+        )
+
+    def test_file_not_found_during_parse_re_raised(self, analyzer, mocker, tmp_path):
+        """FileNotFoundError during parsing is re-raised, not caught."""
+        patent_id = "US-44444444-C1"
+
+        patents_dir = tmp_path / "patents"
+        patents_dir.mkdir()
+        (patents_dir / f"{patent_id}.pdf").write_bytes(b"fake PDF")
+
+        mocker.patch(
+            "SPARC.analyzer.SERP.parse_patent_pdf",
+            side_effect=FileNotFoundError("PDF file vanished"),
+        )
+
+        original_cwd = os.getcwd()
+        os.chdir(tmp_path)
+        try:
+            with pytest.raises(FileNotFoundError, match="PDF file vanished"):
+                analyzer.analyze_single_patent(patent_id, "VanishCo")
+        finally:
+            os.chdir(original_cwd)

tests/test_api_keys.py

@@ -0,0 +1,319 @@
+"""Tests for user-level API key generation, listing, revocation, and authentication.
+
+Covers all acceptance criteria from issue #1673:
+1. Users can create API keys (POST /auth/apikeys)
+2. Users can list their active key IDs (GET /auth/apikeys)
+3. Users can revoke keys (DELETE /auth/apikeys/{key_id})
+4. API requests authenticated with a valid API key work on protected endpoints
+5. Revoked keys are immediately rejected
+6. Plaintext key is shown only at creation time
+
+All tests use mocked DB fixtures and require no live database.
+"""
+
+from datetime import datetime, timezone
+from unittest.mock import MagicMock, patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+from SPARC.auth import (
+    create_access_token,
+    generate_api_key,
+    hash_api_key,
+    verify_api_key,
+)
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+def _make_user():
+    return {
+        "id": 1,
+        "email": "user@test.com",
+        "role": "user",
+        "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+    }
+
+
+def _auth_header(user_dict):
+    """Create an Authorization header with a valid access token."""
+    token = create_access_token(user_dict["id"], user_dict["email"], user_dict["role"])
+    return {"Authorization": f"Bearer {token}"}
+
+
+@pytest.fixture(autouse=True)
+def mock_db(monkeypatch):
+    """Mock the database client used by auth and api endpoints."""
+    db = MagicMock()
+    db.get_user_count.return_value = 0
+    db.get_user_by_id.return_value = None
+    db.get_user_by_email.return_value = None
+    db.authenticate_user.return_value = None
+    db.create_user.return_value = None
+    db.get_all_users.return_value = []
+    db.update_user_role.return_value = None
+    db.delete_user.return_value = False
+    db.create_api_key.return_value = None
+    db.list_api_keys.return_value = []
+    db.delete_api_key.return_value = False
+    db.get_all_api_key_hashes.return_value = []
+
+    with patch("SPARC.api.get_db_client", return_value=db), \
+         patch("SPARC.auth.get_db_client", return_value=db):
+        yield db
+
+
+class TestCreateApiKey:
+    """POST /auth/apikeys"""
+
+    def test_create_key_returns_plaintext_and_id(self, client, mock_db):
+        """Creating a key returns the plaintext key and metadata."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.create_api_key.return_value = {
+            "id": 42,
+            "user_id": user["id"],
+            "label": "my-ci-key",
+            "created_at": datetime(2025, 6, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.post(
+            "/auth/apikeys",
+            json={"label": "my-ci-key"},
+            headers=_auth_header(user),
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["id"] == 42
+        assert len(data["key"]) == 64  # 32 bytes hex = 64 chars
+        assert data["label"] == "my-ci-key"
+        assert "created_at" in data
+
+        # Verify the hash passed to DB is valid for the returned key
+        call_args = mock_db.create_api_key.call_args
+        stored_hash = call_args.kwargs.get("key_hash") or call_args[1].get("key_hash") or call_args[0][1]
+        assert verify_api_key(data["key"], stored_hash)
+
+    def test_create_key_without_label(self, client, mock_db):
+        """Creating a key without a label should work."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.create_api_key.return_value = {
+            "id": 1,
+            "user_id": user["id"],
+            "label": None,
+            "created_at": datetime(2025, 6, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.post(
+            "/auth/apikeys",
+            headers=_auth_header(user),
+        )
+
+        assert response.status_code == 200
+        assert response.json()["label"] is None
+
+    def test_create_key_requires_auth(self, client):
+        """Creating a key without auth should fail."""
+        response = client.post("/auth/apikeys")
+        assert response.status_code == 401
+
+
+class TestListApiKeys:
+    """GET /auth/apikeys"""
+
+    def test_list_keys_returns_metadata_only(self, client, mock_db):
+        """Listing keys should return IDs and labels, not secrets."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.list_api_keys.return_value = [
+            {"id": 1, "label": "key-1", "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc)},
+            {"id": 2, "label": None, "created_at": datetime(2025, 2, 1, tzinfo=timezone.utc)},
+        ]
+
+        response = client.get("/auth/apikeys", headers=_auth_header(user))
+
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data) == 2
+        assert data[0]["id"] == 1
+        assert data[0]["label"] == "key-1"
+        # Ensure no secret key is exposed
+        for item in data:
+            assert "key" not in item
+            assert "key_hash" not in item
+
+    def test_list_keys_empty(self, client, mock_db):
+        """User with no keys gets an empty list."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.list_api_keys.return_value = []
+
+        response = client.get("/auth/apikeys", headers=_auth_header(user))
+
+        assert response.status_code == 200
+        assert response.json() == []
+
+
+class TestRevokeApiKey:
+    """DELETE /auth/apikeys/{key_id}"""
+
+    def test_revoke_existing_key(self, client, mock_db):
+        """Revoking an owned key should succeed."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.delete_api_key.return_value = True
+
+        response = client.delete("/auth/apikeys/42", headers=_auth_header(user))
+
+        assert response.status_code == 200
+        assert "revoked" in response.json()["message"].lower()
+        mock_db.delete_api_key.assert_called_once_with(42, user["id"])
+
+    def test_revoke_nonexistent_key_returns_404(self, client, mock_db):
+        """Revoking a key that doesn't exist (or isn't owned) returns 404."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+        mock_db.delete_api_key.return_value = False
+
+        response = client.delete("/auth/apikeys/999", headers=_auth_header(user))
+
+        assert response.status_code == 404
+
+
+class TestApiKeyAuthentication:
+    """Using X-API-Key header on protected endpoints."""
+
+    def test_valid_api_key_accesses_protected_endpoint(self, client, mock_db):
+        """A valid API key should authenticate and access /auth/me."""
+        user = _make_user()
+        plaintext = generate_api_key()
+        hashed = hash_api_key(plaintext)
+
+        mock_db.get_all_api_key_hashes.return_value = [
+            {"key_hash": hashed, "user_id": user["id"]},
+        ]
+        mock_db.get_user_by_id.return_value = user
+
+        response = client.get("/auth/me", headers={"X-API-Key": plaintext})
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["email"] == user["email"]
+        assert data["id"] == user["id"]
+
+    def test_invalid_api_key_returns_401(self, client, mock_db):
+        """An invalid API key should return 401."""
+        mock_db.get_all_api_key_hashes.return_value = []
+
+        response = client.get("/auth/me", headers={"X-API-Key": "bad-key"})
+
+        assert response.status_code == 401
+        assert "invalid api key" in response.json()["detail"].lower()
+
+    def test_revoked_key_returns_401(self, client, mock_db):
+        """After revocation, using the key should return 401."""
+        # Simulate revoked key: no matching hashes in DB
+        mock_db.get_all_api_key_hashes.return_value = []
+
+        response = client.get("/auth/me", headers={"X-API-Key": "a" * 64})
+
+        assert response.status_code == 401
+
+    def test_api_key_for_deleted_user_returns_401(self, client, mock_db):
+        """An API key whose user no longer exists should return 401."""
+        plaintext = generate_api_key()
+        hashed = hash_api_key(plaintext)
+
+        mock_db.get_all_api_key_hashes.return_value = [
+            {"key_hash": hashed, "user_id": 999},
+        ]
+        mock_db.get_user_by_id.return_value = None  # user deleted
+
+        response = client.get("/auth/me", headers={"X-API-Key": plaintext})
+
+        assert response.status_code == 401
+
+    def test_no_auth_at_all_returns_401(self, client, mock_db):
+        """No auth header at all should return 401."""
+        response = client.get("/auth/me")
+        assert response.status_code == 401
+
+
+class TestApiKeyFullFlow:
+    """End-to-end flow: create key, use it, revoke it, try again."""
+
+    def test_create_use_revoke_flow(self, client, mock_db):
+        """Simulate full lifecycle of an API key."""
+        user = _make_user()
+        mock_db.get_user_by_id.return_value = user
+
+        # Step 1: Create key
+        mock_db.create_api_key.return_value = {
+            "id": 10,
+            "user_id": user["id"],
+            "label": "test",
+            "created_at": datetime(2025, 6, 1, tzinfo=timezone.utc),
+        }
+
+        create_resp = client.post(
+            "/auth/apikeys",
+            json={"label": "test"},
+            headers=_auth_header(user),
+        )
+        assert create_resp.status_code == 200
+        plaintext = create_resp.json()["key"]
+
+        # Capture the hash that was stored
+        call_args = mock_db.create_api_key.call_args
+        stored_hash = call_args.kwargs.get("key_hash") or call_args[0][1]
+
+        # Step 2: Use key on protected endpoint
+        mock_db.get_all_api_key_hashes.return_value = [
+            {"key_hash": stored_hash, "user_id": user["id"]},
+        ]
+
+        use_resp = client.get("/auth/me", headers={"X-API-Key": plaintext})
+        assert use_resp.status_code == 200
+        assert use_resp.json()["email"] == user["email"]
+
+        # Step 3: Revoke key
+        mock_db.delete_api_key.return_value = True
+        revoke_resp = client.delete("/auth/apikeys/10", headers=_auth_header(user))
+        assert revoke_resp.status_code == 200
+
+        # Step 4: Try using revoked key
+        mock_db.get_all_api_key_hashes.return_value = []  # key removed from DB
+        rejected_resp = client.get("/auth/me", headers={"X-API-Key": plaintext})
+        assert rejected_resp.status_code == 401
+
+
+class TestApiKeyHelpers:
+    """Unit tests for key generation and hashing helpers."""
+
+    def test_generate_api_key_length(self):
+        """Generated key should be 64 hex characters (32 bytes)."""
+        key = generate_api_key()
+        assert len(key) == 64
+        # Should be valid hex
+        int(key, 16)
+
+    def test_generate_api_key_uniqueness(self):
+        """Two generated keys should be different."""
+        k1 = generate_api_key()
+        k2 = generate_api_key()
+        assert k1 != k2
+
+    def test_hash_and_verify(self):
+        """hash_api_key and verify_api_key should round-trip correctly."""
+        key = generate_api_key()
+        hashed = hash_api_key(key)
+        assert verify_api_key(key, hashed)
+        assert not verify_api_key("wrong-key", hashed)

tests/test_auth.py

@@ -1,13 +1,29 @@
-"""Tests for JWT authentication flow: register, login, protected routes, refresh, admin access."""
+"""Tests for JWT authentication flow: register, login, protected routes, refresh, admin access.
 
-from datetime import datetime, timezone
+Covers all five scenarios required by issue #1624:
+1. Registration (POST /auth/register)
+2. Login (POST /auth/login)
+3. Protected route access (GET /auth/me) -- valid, missing, expired, wrong-type tokens
+4. Token refresh (POST /auth/refresh)
+5. Admin-only endpoints (GET /admin/users, PATCH role, DELETE user)
+
+All tests use mocked DB fixtures and require no live database.
+"""
+
+from datetime import datetime, timedelta, timezone
 from unittest.mock import MagicMock, patch
 
+import jwt as pyjwt
 import pytest
 from fastapi.testclient import TestClient
 
 from SPARC.api import app
-from SPARC.auth import create_access_token, create_refresh_token
+from SPARC.auth import (
+    JWT_ALGORITHM,
+    JWT_SECRET,
+    create_access_token,
+    create_refresh_token,
+)
 
 
 @pytest.fixture
@@ -171,13 +187,6 @@ class TestGetMe:
 
     def test_expired_token_returns_401(self, client, mock_db):
         """An expired token should return 401."""
-        # Create a token that has already expired
-        from datetime import timedelta
-
-        import jwt as pyjwt
-
-        from SPARC.auth import JWT_ALGORITHM, JWT_SECRET
-
         payload = {
             "sub": "1",
             "email": "user@test.com",
@@ -301,3 +310,193 @@ class TestAdminUsers:
 
         assert response.status_code == 400
         assert "own role" in response.json()["detail"].lower()
+
+    def test_role_change_nonexistent_user_returns_404(self, client, mock_db):
+        """Changing role for a user that does not exist should return 404."""
+        admin = _make_admin_user()
+        mock_db.get_user_by_id.return_value = admin
+        mock_db.update_user_role.return_value = None
+
+        response = client.patch(
+            "/admin/users/999/role",
+            json={"role": "admin"},
+            headers=_auth_header(admin),
+        )
+
+        assert response.status_code == 404
+        assert "not found" in response.json()["detail"].lower()
+
+    def test_regular_user_cannot_change_role(self, client, mock_db):
+        """Non-admin user should receive 403 when trying to change roles."""
+        user = _make_regular_user()
+        mock_db.get_user_by_id.return_value = user
+
+        response = client.patch(
+            "/admin/users/1/role",
+            json={"role": "admin"},
+            headers=_auth_header(user),
+        )
+
+        assert response.status_code == 403
+
+
+class TestAdminDeleteUser:
+    """DELETE /admin/users/{user_id}"""
+
+    def test_admin_can_delete_user(self, client, mock_db):
+        """Admin should be able to delete another user."""
+        admin = _make_admin_user()
+        mock_db.get_user_by_id.return_value = admin
+        mock_db.delete_user.return_value = True
+
+        response = client.delete(
+            "/admin/users/2",
+            headers=_auth_header(admin),
+        )
+
+        assert response.status_code == 200
+        assert "deleted" in response.json()["message"].lower()
+        mock_db.delete_user.assert_called_once_with(2)
+
+    def test_admin_cannot_delete_self(self, client, mock_db):
+        """Admin should not be able to delete themselves."""
+        admin = _make_admin_user()
+        mock_db.get_user_by_id.return_value = admin
+
+        response = client.delete(
+            "/admin/users/1",
+            headers=_auth_header(admin),
+        )
+
+        assert response.status_code == 400
+        assert "yourself" in response.json()["detail"].lower()
+
+    def test_delete_nonexistent_user_returns_404(self, client, mock_db):
+        """Deleting a user that does not exist should return 404."""
+        admin = _make_admin_user()
+        mock_db.get_user_by_id.return_value = admin
+        mock_db.delete_user.return_value = False
+
+        response = client.delete(
+            "/admin/users/999",
+            headers=_auth_header(admin),
+        )
+
+        assert response.status_code == 404
+        assert "not found" in response.json()["detail"].lower()
+
+    def test_regular_user_cannot_delete_user(self, client, mock_db):
+        """Non-admin user should receive 403 when trying to delete users."""
+        user = _make_regular_user()
+        mock_db.get_user_by_id.return_value = user
+
+        response = client.delete(
+            "/admin/users/1",
+            headers=_auth_header(user),
+        )
+
+        assert response.status_code == 403
+
+    def test_no_token_cannot_delete_user(self, client):
+        """Missing token should be rejected for delete endpoint."""
+        response = client.delete("/admin/users/1")
+        assert response.status_code in (401, 403)
+
+
+class TestEdgeCases:
+    """Additional edge-case tests for auth robustness."""
+
+    def test_register_invalid_email_returns_422(self, client, mock_db):
+        """Registration with an invalid email format should return 422."""
+        response = client.post(
+            "/auth/register",
+            json={"email": "not-an-email", "password": "securepass123"},
+        )
+
+        assert response.status_code == 422
+
+    def test_register_short_password_returns_422(self, client, mock_db):
+        """Registration with a password shorter than 8 chars should return 422."""
+        response = client.post(
+            "/auth/register",
+            json={"email": "user@test.com", "password": "short"},
+        )
+
+        assert response.status_code == 422
+
+    def test_register_missing_fields_returns_422(self, client, mock_db):
+        """Registration with missing fields should return 422."""
+        response = client.post("/auth/register", json={})
+        assert response.status_code == 422
+
+    def test_login_missing_fields_returns_422(self, client, mock_db):
+        """Login with missing fields should return 422."""
+        response = client.post("/auth/login", json={"email": "user@test.com"})
+        assert response.status_code == 422
+
+    def test_malformed_token_returns_401(self, client, mock_db):
+        """A completely malformed token string should return 401."""
+        response = client.get(
+            "/auth/me",
+            headers={"Authorization": "Bearer not.a.valid.jwt.token"},
+        )
+        assert response.status_code == 401
+
+    def test_token_with_wrong_secret_returns_401(self, client, mock_db):
+        """A token signed with a different secret should return 401."""
+        payload = {
+            "sub": "1",
+            "email": "user@test.com",
+            "role": "user",
+            "exp": datetime.now(timezone.utc) + timedelta(hours=1),
+            "type": "access",
+        }
+        wrong_secret_token = pyjwt.encode(payload, "wrong-secret", algorithm=JWT_ALGORITHM)
+
+        response = client.get(
+            "/auth/me",
+            headers={"Authorization": f"Bearer {wrong_secret_token}"},
+        )
+        assert response.status_code == 401
+
+    def test_token_for_deleted_user_returns_401(self, client, mock_db):
+        """A valid token for a user no longer in the DB should return 401."""
+        user = _make_regular_user()
+        mock_db.get_user_by_id.return_value = None  # user was deleted
+
+        response = client.get("/auth/me", headers=_auth_header(user))
+        assert response.status_code == 401
+
+    def test_refresh_for_deleted_user_returns_401(self, client, mock_db):
+        """Refreshing a token for a deleted user should return 401."""
+        user = _make_regular_user()
+        mock_db.get_user_by_id.return_value = None
+        refresh = create_refresh_token(user["id"], user["email"], user["role"])
+
+        response = client.post(
+            "/auth/refresh", json={"refresh_token": refresh}
+        )
+        assert response.status_code == 401
+
+    def test_login_returns_decodable_tokens(self, client, mock_db):
+        """Tokens returned by login should be decodable and contain expected claims."""
+        user = _make_regular_user()
+        mock_db.authenticate_user.return_value = user
+
+        response = client.post(
+            "/auth/login",
+            json={"email": "user@test.com", "password": "correctpassword"},
+        )
+
+        data = response.json()
+        access_payload = pyjwt.decode(
+            data["access_token"], JWT_SECRET, algorithms=[JWT_ALGORITHM]
+        )
+        assert access_payload["sub"] == str(user["id"])
+        assert access_payload["email"] == user["email"]
+        assert access_payload["type"] == "access"
+
+        refresh_payload = pyjwt.decode(
+            data["refresh_token"], JWT_SECRET, algorithms=[JWT_ALGORITHM]
+        )
+        assert refresh_payload["type"] == "refresh"

tests/test_company_name_validation.py

@@ -0,0 +1,157 @@
+"""Tests for company name input validation on analysis endpoints."""
+
+from datetime import datetime
+from unittest.mock import Mock
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+from SPARC.types import CompanyAnalysisResult
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture
+def mock_analyzer(mocker):
+    """Mock the global analyzer so valid requests succeed."""
+    mock = Mock()
+    mock._analyze_company_safe.return_value = CompanyAnalysisResult(
+        company_name="nvidia",
+        analysis="Test analysis",
+        patent_count=1,
+        success=True,
+        timestamp=datetime.now(),
+    )
+    mocker.patch("SPARC.api._analyzer", mock)
+    return mock
+
+
+class TestCompanyNameValidation:
+    """Test that company names are validated on analysis endpoints."""
+
+    # --- Too short ---
+
+    def test_single_char_rejected(self, client, mock_analyzer):
+        """A one-character company name should be rejected."""
+        response = client.get("/analyze/X")
+        assert response.status_code == 422
+
+    # --- Too long ---
+
+    def test_over_100_chars_rejected(self, client, mock_analyzer):
+        """A company name longer than 100 characters should be rejected."""
+        long_name = "A" * 101
+        response = client.get(f"/analyze/{long_name}")
+        assert response.status_code == 422
+
+    # --- Special characters ---
+
+    @pytest.mark.parametrize(
+        "bad_name",
+        [
+            "nvidia!",
+            "intel@corp",
+            "test#company",
+            "foo$bar",
+            "a%b",
+            "x^y",
+            "semi;colon",
+            "drop'table",
+            'say"hello',
+            "path/traversal",
+            "back\\slash",
+            "pipe|char",
+            "star*glob",
+            "question?mark",
+            "<script>",
+            "curly{brace}",
+            "equal=sign",
+            "plus+plus",
+            "comma,separated",
+        ],
+    )
+    def test_special_chars_rejected(self, client, mock_analyzer, bad_name):
+        """Company names with disallowed special characters should be rejected."""
+        response = client.get(f"/analyze/{bad_name}")
+        assert response.status_code == 422
+
+    # --- Valid names ---
+
+    @pytest.mark.parametrize(
+        "valid_name",
+        [
+            "nvidia",
+            "Intel",
+            "TSMC",
+            "Texas Instruments",
+            "Johnson-Johnson",
+            "AT&T",
+            "St. Jude Medical",
+            "3M",
+            "21st Century Fox",
+            "ab",  # minimum length
+            "A" * 100,  # maximum length
+        ],
+    )
+    def test_valid_names_accepted(self, client, mock_analyzer, valid_name):
+        """Valid company names should be accepted (200, not 422)."""
+        response = client.get(f"/analyze/{valid_name}")
+        # Should not be a validation error; 200 or other non-422 status is fine
+        assert response.status_code != 422
+
+    # --- Batch endpoint validation ---
+
+    def test_batch_too_short_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names that are too short."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["X"]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_too_long_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names that are too long."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["A" * 101]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_special_chars_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names with special chars."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["nvidia!", "intel"]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_valid_names_accepted(self, client, mock_analyzer):
+        """Batch endpoint should accept valid company names."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["nvidia", "Intel", "AT&T"]},
+        )
+        assert response.status_code != 422
+
+    # --- Name must start with alphanumeric ---
+
+    def test_leading_space_rejected(self, client, mock_analyzer):
+        """Company name starting with a space should be rejected."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": [" nvidia"]},
+        )
+        assert response.status_code == 422
+
+    def test_leading_hyphen_rejected(self, client, mock_analyzer):
+        """Company name starting with a hyphen should be rejected."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["-nvidia"]},
+        )
+        assert response.status_code == 422

tests/test_export.py

@@ -0,0 +1,224 @@
+"""Tests for export endpoints: CSV and PDF export of analysis results.
+
+Covers issue #1655:
+- GET /export/{company_name} (CSV export)
+- GET /export/{company_name}/pdf (PDF export)
+
+All tests mock the database layer and use JWT auth fixtures from test_auth patterns.
+"""
+
+from datetime import datetime, timezone
+from unittest.mock import MagicMock, patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+from SPARC.auth import create_access_token
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture(autouse=True)
+def mock_db():
+    """Mock the database client used by export and auth endpoints."""
+    db = MagicMock()
+
+    # Default: user exists for auth
+    db.get_user_by_id.return_value = {
+        "id": 1,
+        "email": "user@test.com",
+        "role": "user",
+        "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+    }
+
+    # Mock get_conn for export queries
+    mock_cursor = MagicMock()
+    mock_conn = MagicMock()
+    mock_conn.cursor.return_value.__enter__ = MagicMock(return_value=mock_cursor)
+    mock_conn.cursor.return_value.__exit__ = MagicMock(return_value=False)
+    db.get_conn.return_value.__enter__ = MagicMock(return_value=mock_conn)
+    db.get_conn.return_value.__exit__ = MagicMock(return_value=False)
+    db._mock_cursor = mock_cursor
+
+    with patch("SPARC.api.get_db_client", return_value=db), \
+         patch("SPARC.auth.get_db_client", return_value=db):
+        yield db
+
+
+def _auth_header():
+    """Create an Authorization header with a valid access token."""
+    token = create_access_token(1, "user@test.com", "user")
+    return {"Authorization": f"Bearer {token}"}
+
+
+def _sample_rows():
+    """Return sample llm_messages rows as tuples (matching cursor.fetchall format)."""
+    return [
+        (
+            "NVIDIA",
+            "company_analysis",
+            "anthropic/claude-3.5-sonnet",
+            "Strong AI patent portfolio with focus on GPU architectures.",
+            datetime(2025, 6, 15, 10, 30, 0),
+        ),
+        (
+            "NVIDIA",
+            "patent_analysis",
+            "openai/gpt-4o",
+            "Patent US-12345678-B2 covers novel tensor core design.",
+            datetime(2025, 6, 14, 9, 0, 0),
+        ),
+    ]
+
+
+class TestCSVExport:
+    """GET /export/{company_name} -- CSV export."""
+
+    def test_csv_export_success(self, client, mock_db):
+        """Valid company with results returns a CSV file."""
+        mock_db._mock_cursor.fetchall.return_value = _sample_rows()
+
+        response = client.get("/export/NVIDIA", headers=_auth_header())
+
+        assert response.status_code == 200
+        assert response.headers["content-type"].startswith("text/csv")
+        assert "attachment" in response.headers.get("content-disposition", "")
+        assert "sparc_nvidia_export.csv" in response.headers["content-disposition"]
+
+        # Verify CSV content (CSV uses \r\n line endings)
+        lines = response.text.strip().split("\n")
+        assert len(lines) == 3  # header + 2 data rows
+        assert lines[0].strip() == "company_name,analysis_type,model,analysis,timestamp"
+        assert "NVIDIA" in lines[1]
+        assert "company_analysis" in lines[1]
+
+    def test_csv_export_no_results_returns_404(self, client, mock_db):
+        """Unknown company returns 404."""
+        mock_db._mock_cursor.fetchall.return_value = []
+
+        response = client.get("/export/nonexistent", headers=_auth_header())
+
+        assert response.status_code == 404
+        assert "No analysis results found" in response.json()["detail"]
+
+    def test_csv_export_unauthenticated_returns_401(self, client):
+        """Request without token returns 401."""
+        response = client.get("/export/NVIDIA")
+        assert response.status_code == 401
+
+    def test_csv_export_invalid_token_returns_401(self, client):
+        """Request with invalid token returns 401."""
+        response = client.get(
+            "/export/NVIDIA",
+            headers={"Authorization": "Bearer invalid.token.here"},
+        )
+        assert response.status_code == 401
+
+    def test_csv_export_filename_sanitization(self, client, mock_db):
+        """Company names with spaces get sanitized in the filename."""
+        mock_db._mock_cursor.fetchall.return_value = [
+            (
+                "Tesla Motors",
+                "company_analysis",
+                "anthropic/claude-3.5-sonnet",
+                "EV patent portfolio analysis.",
+                datetime(2025, 6, 15, 10, 0, 0),
+            ),
+        ]
+
+        response = client.get("/export/Tesla Motors", headers=_auth_header())
+
+        assert response.status_code == 200
+        assert "tesla_motors" in response.headers["content-disposition"]
+
+    def test_csv_export_single_row(self, client, mock_db):
+        """Single analysis result produces valid CSV with one data row."""
+        mock_db._mock_cursor.fetchall.return_value = [_sample_rows()[0]]
+
+        response = client.get("/export/NVIDIA", headers=_auth_header())
+
+        assert response.status_code == 200
+        lines = response.text.strip().split("\n")
+        assert len(lines) == 2  # header + 1 data row
+
+
+class TestPDFExport:
+    """GET /export/{company_name}/pdf -- PDF report export."""
+
+    def test_pdf_export_success(self, client, mock_db):
+        """Valid company with results returns a PDF file."""
+        mock_db._mock_cursor.fetchall.return_value = _sample_rows()
+
+        response = client.get("/export/NVIDIA/pdf", headers=_auth_header())
+
+        assert response.status_code == 200
+        assert response.headers["content-type"] == "application/pdf"
+        assert "attachment" in response.headers.get("content-disposition", "")
+        # PDF files start with %PDF
+        assert response.content[:4] == b"%PDF"
+
+    def test_pdf_export_no_results_returns_404(self, client, mock_db):
+        """Unknown company returns 404."""
+        mock_db._mock_cursor.fetchall.return_value = []
+
+        response = client.get("/export/nonexistent/pdf", headers=_auth_header())
+
+        assert response.status_code == 404
+        assert "No analysis results found" in response.json()["detail"]
+
+    def test_pdf_export_unauthenticated_returns_401(self, client):
+        """Request without token returns 401."""
+        response = client.get("/export/NVIDIA/pdf")
+        assert response.status_code == 401
+
+    def test_pdf_export_invalid_token_returns_401(self, client):
+        """Request with invalid token returns 401."""
+        response = client.get(
+            "/export/NVIDIA/pdf",
+            headers={"Authorization": "Bearer invalid.token.here"},
+        )
+        assert response.status_code == 401
+
+    def test_pdf_export_filename_contains_date(self, client, mock_db):
+        """PDF filename includes the analysis date."""
+        mock_db._mock_cursor.fetchall.return_value = _sample_rows()
+
+        response = client.get("/export/NVIDIA/pdf", headers=_auth_header())
+
+        assert response.status_code == 200
+        disposition = response.headers["content-disposition"]
+        assert "nvidia-analysis-" in disposition
+        assert ".pdf" in disposition
+
+    def test_pdf_export_special_chars_in_response(self, client, mock_db):
+        """Analysis text with XML-special chars (<, >, &) does not break PDF generation."""
+        rows = [
+            (
+                "TestCo",
+                "company_analysis",
+                "anthropic/claude-3.5-sonnet",
+                "Revenue > $1B & growth <20% for Q4. Test <html> escaping.",
+                datetime(2025, 6, 15, 10, 0, 0),
+            ),
+        ]
+        mock_db._mock_cursor.fetchall.return_value = rows
+
+        response = client.get("/export/TestCo/pdf", headers=_auth_header())
+
+        assert response.status_code == 200
+        assert response.content[:4] == b"%PDF"
+
+    def test_pdf_export_multiple_analyses(self, client, mock_db):
+        """Multiple analysis records produce a valid PDF with content."""
+        mock_db._mock_cursor.fetchall.return_value = _sample_rows()
+
+        response = client.get("/export/NVIDIA/pdf", headers=_auth_header())
+
+        assert response.status_code == 200
+        # PDF should have reasonable size (more than just headers)
+        assert len(response.content) > 500

tests/test_pagination.py

@@ -0,0 +1,169 @@
+"""Tests for cursor-based pagination on /analyze/batch GET and /jobs endpoints."""
+
+from datetime import datetime, timedelta
+from unittest.mock import Mock, patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+def _make_analysis_row(id_: int, minutes_ago: int = 0, company: str = "nvidia"):
+    """Create a fake analysis row dict."""
+    ts = datetime.now() - timedelta(minutes=minutes_ago)
+    return {
+        "id": id_,
+        "company_name": company,
+        "analysis_type": "patent_portfolio",
+        "model": "openai/gpt-4o",
+        "response": f"Analysis for {company}",
+        "timestamp": ts,
+    }
+
+
+def _make_job_row(job_id: str, minutes_ago: int = 0, status: str = "completed"):
+    """Create a fake job row dict."""
+    ts = datetime.now() - timedelta(minutes=minutes_ago)
+    return {
+        "job_id": job_id,
+        "status": status,
+        "progress": 100 if status == "completed" else 0,
+        "total_companies": 1,
+        "completed_companies": 1 if status == "completed" else 0,
+        "result": None,
+        "error": None,
+        "created_at": ts,
+    }
+
+
+class TestAnalyzeBatchGetPagination:
+    """Test cursor-based pagination on GET /analyze/batch."""
+
+    @patch("SPARC.api._get_job_db")
+    def test_returns_items_and_no_cursor_when_less_than_limit(self, mock_get_db, client):
+        """When fewer results than limit, next_cursor should be null."""
+        db = Mock()
+        db.list_analyses.return_value = [
+            _make_analysis_row(1, minutes_ago=10),
+            _make_analysis_row(2, minutes_ago=20),
+        ]
+        mock_get_db.return_value = db
+
+        response = client.get("/analyze/batch?limit=10")
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data["items"]) == 2
+        assert data["next_cursor"] is None
+
+    @patch("SPARC.api._get_job_db")
+    def test_returns_cursor_when_more_results_exist(self, mock_get_db, client):
+        """When more results exist than limit, next_cursor should be set."""
+        db = Mock()
+        # Return limit+1 rows to simulate more data
+        rows = [_make_analysis_row(i, minutes_ago=i) for i in range(4)]
+        db.list_analyses.return_value = rows
+        mock_get_db.return_value = db
+
+        response = client.get("/analyze/batch?limit=3")
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data["items"]) == 3
+        assert data["next_cursor"] is not None
+
+    @patch("SPARC.api._get_job_db")
+    def test_cursor_passed_to_db(self, mock_get_db, client):
+        """The cursor query param should be forwarded to the database layer."""
+        db = Mock()
+        db.list_analyses.return_value = []
+        mock_get_db.return_value = db
+
+        client.get("/analyze/batch?cursor=2025-01-01T00:00:00|42")
+        db.list_analyses.assert_called_once()
+        call_kwargs = db.list_analyses.call_args
+        assert call_kwargs.kwargs.get("cursor") == "2025-01-01T00:00:00|42" or \
+            (call_kwargs[1].get("cursor") == "2025-01-01T00:00:00|42" if len(call_kwargs) > 1 else False)
+
+    @patch("SPARC.api._get_job_db")
+    def test_default_limit_is_50(self, mock_get_db, client):
+        """Default limit should be 50."""
+        db = Mock()
+        db.list_analyses.return_value = []
+        mock_get_db.return_value = db
+
+        client.get("/analyze/batch")
+        call_kwargs = db.list_analyses.call_args
+        # The endpoint requests limit+1 from DB, so 51
+        assert 51 in call_kwargs.args or call_kwargs.kwargs.get("limit") == 51
+
+    def test_limit_over_200_rejected(self, client):
+        """Limit > 200 should be rejected with 422."""
+        response = client.get("/analyze/batch?limit=201")
+        assert response.status_code == 422
+
+    def test_limit_zero_rejected(self, client):
+        """Limit < 1 should be rejected with 422."""
+        response = client.get("/analyze/batch?limit=0")
+        assert response.status_code == 422
+
+    @patch("SPARC.api._get_job_db")
+    def test_company_name_filter(self, mock_get_db, client):
+        """The company_name filter should be forwarded to the database."""
+        db = Mock()
+        db.list_analyses.return_value = []
+        mock_get_db.return_value = db
+
+        client.get("/analyze/batch?company_name=intel")
+        call_kwargs = db.list_analyses.call_args
+        assert call_kwargs.kwargs.get("company_name") == "intel" or \
+            "intel" in (call_kwargs.args if call_kwargs.args else [])
+
+    @patch("SPARC.api._get_job_db")
+    def test_empty_result_set(self, mock_get_db, client):
+        """Empty result set returns empty items and null cursor."""
+        db = Mock()
+        db.list_analyses.return_value = []
+        mock_get_db.return_value = db
+
+        response = client.get("/analyze/batch")
+        assert response.status_code == 200
+        data = response.json()
+        assert data["items"] == []
+        assert data["next_cursor"] is None
+
+
+class TestJobsPaginationDefaults:
+    """Test that /jobs endpoint uses updated defaults."""
+
+    @patch("SPARC.api._get_job_db")
+    def test_default_limit_is_50(self, mock_get_db, client):
+        """Default limit should now be 50."""
+        db = Mock()
+        db.list_jobs.return_value = []
+        mock_get_db.return_value = db
+
+        client.get("/jobs")
+        call_kwargs = db.list_jobs.call_args
+        # Endpoint requests limit+1 from DB, so 51
+        assert 51 in call_kwargs.args or call_kwargs.kwargs.get("limit") == 51
+
+    def test_limit_over_200_rejected(self, client):
+        """Limit > 200 should be rejected with 422."""
+        response = client.get("/jobs?limit=201")
+        assert response.status_code == 422
+
+    @patch("SPARC.api._get_job_db")
+    def test_limit_200_accepted(self, mock_get_db, client):
+        """Limit of exactly 200 should be accepted."""
+        db = Mock()
+        db.list_jobs.return_value = []
+        mock_get_db.return_value = db
+
+        response = client.get("/jobs?limit=200")
+        assert response.status_code == 200

tests/test_rate_limit_admin.py

@@ -0,0 +1,178 @@
+"""Tests for the /admin/rate-limits endpoint."""
+
+from unittest.mock import patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC import api
+from SPARC.api import app
+from SPARC.auth import UserResponse
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture(autouse=True)
+def reset_stats():
+    """Reset rate limit stats between tests."""
+    api._rate_limit_stats.clear()
+    api._rejected_log.clear()
+    yield
+    api._rate_limit_stats.clear()
+    api._rejected_log.clear()
+
+
+def _mock_admin():
+    """Return a mock admin user."""
+    return UserResponse(id=1, email="admin@test.com", role="admin", created_at="2025-01-01T00:00:00")
+
+
+def _mock_user():
+    """Return a mock non-admin user."""
+    return UserResponse(id=2, email="user@test.com", role="user", created_at="2025-01-01T00:00:00")
+
+
+class TestRateLimitAdminEndpoint:
+    """Test GET /admin/rate-limits."""
+
+    def test_admin_can_access(self, client):
+        """Admin users should be able to access the rate-limits endpoint."""
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            assert response.status_code == 200
+            data = response.json()
+            assert "rate_limits" in data
+            assert isinstance(data["rate_limits"], list)
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_non_admin_rejected(self, client):
+        """Non-admin users should get 401/403."""
+        response = client.get("/admin/rate-limits")
+        assert response.status_code in (401, 403)
+
+    def test_returns_configured_endpoints(self, client):
+        """Should list all rate-limited endpoints."""
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            assert response.status_code == 200
+            data = response.json()
+            endpoints = [rl["endpoint"] for rl in data["rate_limits"]]
+            assert "/auth/register" in endpoints
+            assert "/auth/login" in endpoints
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_empty_state_shows_zero_counts(self, client):
+        """When no requests have been made, counts should be zero."""
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            for rl in data["rate_limits"]:
+                assert rl["total_requests"] == 0
+                assert rl["rejected_requests"] == 0
+                assert rl["by_ip"] == []
+            assert data["throttled_24h"] == 0
+            assert data["throttled_over_time"] == []
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_tracks_requests(self, client):
+        """After making requests, the stats should reflect them."""
+        api._track_rate_limit_request("/auth/login", "127.0.0.1")
+        api._track_rate_limit_request("/auth/login", "127.0.0.1")
+        api._track_rate_limit_request("/auth/login", "192.168.1.1", rejected=True)
+
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            login_stats = next(rl for rl in data["rate_limits"] if rl["endpoint"] == "/auth/login")
+            assert login_stats["total_requests"] == 3
+            assert login_stats["rejected_requests"] == 1
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_includes_limit_config(self, client):
+        """Each endpoint entry should include the rate limit config string."""
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            for rl in data["rate_limits"]:
+                assert "limit" in rl
+                assert isinstance(rl["limit"], str)
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_per_ip_breakdown(self, client):
+        """Stats should include per-IP breakdown with total and rejected counts."""
+        api._track_rate_limit_request("/auth/login", "10.0.0.1")
+        api._track_rate_limit_request("/auth/login", "10.0.0.1", rejected=True)
+        api._track_rate_limit_request("/auth/login", "10.0.0.2")
+
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            login_stats = next(rl for rl in data["rate_limits"] if rl["endpoint"] == "/auth/login")
+            by_ip = login_stats["by_ip"]
+            assert len(by_ip) == 2
+            ip1 = next(entry for entry in by_ip if entry["ip"] == "10.0.0.1")
+            assert ip1["total"] == 2
+            assert ip1["rejected"] == 1
+            ip2 = next(entry for entry in by_ip if entry["ip"] == "10.0.0.2")
+            assert ip2["total"] == 1
+            assert ip2["rejected"] == 0
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_throttled_24h_count(self, client):
+        """Should report total throttled requests in the last 24 hours."""
+        api._track_rate_limit_request("/auth/login", "10.0.0.1", rejected=True)
+        api._track_rate_limit_request("/auth/register", "10.0.0.2", rejected=True)
+
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            assert data["throttled_24h"] == 2
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_throttled_over_time_structure(self, client):
+        """Throttled-over-time should be a list of {timestamp, count} buckets."""
+        api._track_rate_limit_request("/auth/login", "10.0.0.1", rejected=True)
+
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            assert len(data["throttled_over_time"]) >= 1
+            entry = data["throttled_over_time"][0]
+            assert "timestamp" in entry
+            assert "count" in entry
+            assert entry["count"] >= 1
+        finally:
+            app.dependency_overrides.clear()
+
+    def test_response_shape_matches_contract(self, client):
+        """The full response should match the expected shape for the frontend."""
+        app.dependency_overrides[api.get_current_admin] = _mock_admin
+        try:
+            response = client.get("/admin/rate-limits")
+            data = response.json()
+            # Top-level keys
+            assert set(data.keys()) == {"rate_limits", "throttled_24h", "throttled_over_time"}
+            # Each rate_limit entry
+            for rl in data["rate_limits"]:
+                assert set(rl.keys()) == {"endpoint", "limit", "total_requests", "rejected_requests", "by_ip"}
+        finally:
+            app.dependency_overrides.clear()

tests/test_storage.py

@@ -0,0 +1,263 @@
+"""Tests for S3/MinIO storage backend in storage.py.
+
+Covers issue #1660:
+- S3StorageBackend read, write, exists, path_for
+- Error handling: NoSuchKey, generic S3 errors, bucket auto-creation
+- get_storage_backend() factory function
+- LocalStorageBackend (basic sanity checks)
+"""
+
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from SPARC.storage import LocalStorageBackend, S3StorageBackend, get_storage_backend
+
+
+# ---------- S3StorageBackend ----------
+
+class TestS3StorageBackend:
+    """Tests for the S3-compatible storage backend."""
+
+    @pytest.fixture
+    def s3_backend(self):
+        """Create an S3StorageBackend with a fully mocked boto3 client."""
+        with patch.dict("sys.modules", {"boto3": MagicMock()}):
+            import boto3 as mock_boto
+            mock_s3 = MagicMock()
+            mock_boto.client.return_value = mock_s3
+            mock_s3.head_bucket.return_value = {}
+
+            backend = S3StorageBackend(
+                bucket="test-bucket",
+                endpoint_url="http://minio:9000",
+                access_key="minioadmin",
+                secret_key="minioadmin",
+            )
+            # Expose mock for assertions
+            backend._mock_s3 = mock_s3
+            yield backend
+
+    def test_write_puts_object(self, s3_backend):
+        """write() calls put_object with correct bucket, key, and body."""
+        s3_backend.write("US-12345678-B2.pdf", b"PDF content here")
+
+        s3_backend._mock_s3.put_object.assert_called_once_with(
+            Bucket="test-bucket",
+            Key="US-12345678-B2.pdf",
+            Body=b"PDF content here",
+            ContentType="application/pdf",
+        )
+
+    def test_read_returns_body(self, s3_backend):
+        """read() returns the Body content from get_object."""
+        mock_body = MagicMock()
+        mock_body.read.return_value = b"PDF data"
+        s3_backend._mock_s3.get_object.return_value = {"Body": mock_body}
+
+        result = s3_backend.read("US-12345678-B2.pdf")
+
+        assert result == b"PDF data"
+        s3_backend._mock_s3.get_object.assert_called_once_with(
+            Bucket="test-bucket",
+            Key="US-12345678-B2.pdf",
+        )
+
+    def test_read_nosuchkey_raises_file_not_found(self, s3_backend):
+        """read() raises FileNotFoundError when object does not exist."""
+        # Create a NoSuchKey exception class on the mock
+        nosuchkey = type("NoSuchKey", (Exception,), {})
+        s3_backend._mock_s3.exceptions.NoSuchKey = nosuchkey
+        s3_backend._mock_s3.get_object.side_effect = nosuchkey("not found")
+
+        # Reassign s3 to trigger the except branch
+        s3_backend.s3 = s3_backend._mock_s3
+
+        with pytest.raises(FileNotFoundError, match="S3 object not found"):
+            s3_backend.read("missing.pdf")
+
+    def test_read_generic_404_raises_file_not_found(self, s3_backend):
+        """read() handles generic 404 errors from S3-compatible APIs."""
+        nosuchkey = type("NoSuchKey", (Exception,), {})
+        s3_backend._mock_s3.exceptions.NoSuchKey = nosuchkey
+        s3_backend.s3 = s3_backend._mock_s3
+        s3_backend.s3.get_object.side_effect = Exception("An error occurred (404)")
+
+        with pytest.raises(FileNotFoundError, match="S3 object not found"):
+            s3_backend.read("missing.pdf")
+
+    def test_read_other_error_re_raises(self, s3_backend):
+        """read() re-raises non-404 errors."""
+        nosuchkey = type("NoSuchKey", (Exception,), {})
+        s3_backend._mock_s3.exceptions.NoSuchKey = nosuchkey
+        s3_backend.s3 = s3_backend._mock_s3
+        s3_backend.s3.get_object.side_effect = Exception("Internal server error")
+
+        with pytest.raises(Exception, match="Internal server error"):
+            s3_backend.read("some-file.pdf")
+
+    def test_exists_returns_true_for_existing_object(self, s3_backend):
+        """exists() returns True when head_object succeeds with content."""
+        s3_backend._mock_s3.head_object.return_value = {"ContentLength": 1024}
+
+        assert s3_backend.exists("US-12345678-B2.pdf") is True
+
+    def test_exists_returns_false_for_missing_object(self, s3_backend):
+        """exists() returns False when head_object raises an exception."""
+        s3_backend._mock_s3.head_object.side_effect = Exception("Not Found")
+
+        assert s3_backend.exists("missing.pdf") is False
+
+    def test_exists_returns_false_for_zero_length(self, s3_backend):
+        """exists() returns False when object has zero content length."""
+        s3_backend._mock_s3.head_object.return_value = {"ContentLength": 0}
+
+        assert s3_backend.exists("empty.pdf") is False
+
+    def test_path_for_returns_s3_uri(self, s3_backend):
+        """path_for() returns an s3:// URI."""
+        path = s3_backend.path_for("US-12345678-B2.pdf")
+
+        assert path == "s3://test-bucket/US-12345678-B2.pdf"
+
+    def test_constructor_creates_bucket_if_missing(self):
+        """Constructor creates the bucket if head_bucket fails."""
+        with patch.dict("sys.modules", {"boto3": MagicMock()}):
+            import boto3 as mock_boto
+            mock_s3 = MagicMock()
+            mock_boto.client.return_value = mock_s3
+            mock_s3.head_bucket.side_effect = Exception("Bucket not found")
+
+            S3StorageBackend(
+                bucket="new-bucket",
+                endpoint_url="http://minio:9000",
+                access_key="admin",
+                secret_key="admin",
+            )
+
+            mock_s3.create_bucket.assert_called_once_with(Bucket="new-bucket")
+
+    def test_constructor_handles_bucket_creation_failure(self):
+        """Constructor logs warning but does not crash if bucket creation fails."""
+        with patch.dict("sys.modules", {"boto3": MagicMock()}):
+            import boto3 as mock_boto
+            mock_s3 = MagicMock()
+            mock_boto.client.return_value = mock_s3
+            mock_s3.head_bucket.side_effect = Exception("Bucket not found")
+            mock_s3.create_bucket.side_effect = Exception("Permission denied")
+
+            # Should not raise
+            backend = S3StorageBackend(
+                bucket="locked-bucket",
+                endpoint_url="http://minio:9000",
+                access_key="admin",
+                secret_key="admin",
+            )
+            assert backend.bucket == "locked-bucket"
+
+    def test_constructor_passes_endpoint_and_credentials(self):
+        """Constructor passes endpoint_url and credentials to boto3.client."""
+        with patch.dict("sys.modules", {"boto3": MagicMock()}):
+            import boto3 as mock_boto
+            mock_s3 = MagicMock()
+            mock_boto.client.return_value = mock_s3
+
+            S3StorageBackend(
+                bucket="test",
+                endpoint_url="http://minio:9000",
+                access_key="mykey",
+                secret_key="mysecret",
+            )
+
+            mock_boto.client.assert_called_with(
+                "s3",
+                endpoint_url="http://minio:9000",
+                aws_access_key_id="mykey",
+                aws_secret_access_key="mysecret",
+            )
+
+
+# ---------- LocalStorageBackend ----------
+
+class TestLocalStorageBackend:
+    """Basic sanity checks for the local filesystem backend."""
+
+    def test_write_and_read(self, tmp_path):
+        """Write and read round-trip produces identical content."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+        backend.write("test.pdf", b"hello world")
+
+        result = backend.read("test.pdf")
+        assert result == b"hello world"
+
+    def test_read_missing_file_raises(self, tmp_path):
+        """Reading a non-existent file raises FileNotFoundError."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+
+        with pytest.raises(FileNotFoundError):
+            backend.read("nonexistent.pdf")
+
+    def test_exists_true_for_written_file(self, tmp_path):
+        """exists() returns True after writing a file."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+        backend.write("test.pdf", b"data")
+
+        assert backend.exists("test.pdf") is True
+
+    def test_exists_false_for_missing_file(self, tmp_path):
+        """exists() returns False for non-existent file."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+
+        assert backend.exists("missing.pdf") is False
+
+    def test_exists_false_for_empty_file(self, tmp_path):
+        """exists() returns False for zero-length file."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+        backend.write("empty.pdf", b"")
+
+        assert backend.exists("empty.pdf") is False
+
+    def test_path_for_returns_full_path(self, tmp_path):
+        """path_for() returns the full filesystem path."""
+        backend = LocalStorageBackend(base_dir=str(tmp_path))
+        path = backend.path_for("test.pdf")
+
+        assert path == str(tmp_path / "test.pdf")
+
+
+# ---------- get_storage_backend() factory ----------
+
+class TestGetStorageBackend:
+    """Tests for the storage backend factory function."""
+
+    @patch("SPARC.storage.config")
+    def test_returns_local_backend_by_default(self, mock_config):
+        """Default config returns LocalStorageBackend."""
+        mock_config.storage_backend = "local"
+
+        backend = get_storage_backend()
+
+        assert isinstance(backend, LocalStorageBackend)
+
+    @patch("SPARC.storage.config")
+    def test_returns_s3_backend_when_configured(self, mock_config):
+        """Setting storage_backend=s3 returns S3StorageBackend."""
+        mock_config.storage_backend = "s3"
+        mock_config.s3_bucket = "test-bucket"
+        mock_config.s3_endpoint_url = "http://minio:9000"
+        mock_config.s3_access_key = "key"
+        mock_config.s3_secret_key = "secret"
+
+        with patch.dict("sys.modules", {"boto3": MagicMock()}):
+            backend = get_storage_backend()
+
+        assert isinstance(backend, S3StorageBackend)
+
+    @patch("SPARC.storage.config")
+    def test_case_insensitive_backend_selection(self, mock_config):
+        """Backend selection is case-insensitive."""
+        mock_config.storage_backend = "LOCAL"
+
+        backend = get_storage_backend()
+
+        assert isinstance(backend, LocalStorageBackend)

tests/test_tracked_companies.py

@@ -0,0 +1,387 @@
+"""Tests for tracked company admin endpoints and scheduler integration.
+
+Covers issue #1656:
+- GET /admin/tracked (list tracked companies)
+- POST /admin/tracked (add a tracked company)
+- DELETE /admin/tracked/{company_name} (remove a tracked company)
+- GET /admin/alerts (list alerts)
+- scheduler.run_scheduled_analysis() integration
+
+All tests mock the database layer and use JWT auth fixtures.
+"""
+
+from datetime import datetime, timezone
+from unittest.mock import MagicMock, patch, call
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+from SPARC.auth import create_access_token
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture(autouse=True)
+def mock_db():
+    """Mock the database client used by admin and auth endpoints."""
+    db = MagicMock()
+
+    # Default admin user for auth
+    db.get_user_by_id.return_value = {
+        "id": 1,
+        "email": "admin@test.com",
+        "role": "admin",
+        "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+    }
+
+    with patch("SPARC.api.get_db_client", return_value=db), \
+         patch("SPARC.auth.get_db_client", return_value=db):
+        yield db
+
+
+def _admin_header():
+    """Create an Authorization header with a valid admin access token."""
+    token = create_access_token(1, "admin@test.com", "admin")
+    return {"Authorization": f"Bearer {token}"}
+
+
+def _user_header():
+    """Create an Authorization header with a regular user access token."""
+    token = create_access_token(2, "user@test.com", "user")
+    return {"Authorization": f"Bearer {token}"}
+
+
+# ---------- GET /admin/tracked ----------
+
+class TestListTrackedCompanies:
+    """GET /admin/tracked"""
+
+    def test_list_tracked_returns_companies(self, client, mock_db):
+        """Admin can list tracked companies."""
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "NVIDIA", "last_patent_count": 120, "last_analyzed": "2025-06-15"},
+            {"company_name": "AMD", "last_patent_count": 80, "last_analyzed": "2025-06-14"},
+        ]
+
+        response = client.get("/admin/tracked", headers=_admin_header())
+
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data) == 2
+        assert data[0]["company_name"] == "NVIDIA"
+
+    def test_list_tracked_empty(self, client, mock_db):
+        """Returns empty list when no companies are tracked."""
+        mock_db.list_tracked_companies.return_value = []
+
+        response = client.get("/admin/tracked", headers=_admin_header())
+
+        assert response.status_code == 200
+        assert response.json() == []
+
+    def test_list_tracked_requires_admin(self, client, mock_db):
+        """Regular user cannot access tracked companies list."""
+        mock_db.get_user_by_id.return_value = {
+            "id": 2,
+            "email": "user@test.com",
+            "role": "user",
+            "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.get("/admin/tracked", headers=_user_header())
+
+        assert response.status_code == 403
+
+    def test_list_tracked_unauthenticated(self, client):
+        """Unauthenticated request returns 401."""
+        response = client.get("/admin/tracked")
+        assert response.status_code == 401
+
+
+# ---------- POST /admin/tracked ----------
+
+class TestAddTrackedCompany:
+    """POST /admin/tracked"""
+
+    def test_add_tracked_company_success(self, client, mock_db):
+        """Admin can add a company to tracking."""
+        mock_db.add_tracked_company.return_value = {
+            "company_name": "Intel",
+            "last_patent_count": 0,
+            "last_analyzed": None,
+        }
+
+        response = client.post(
+            "/admin/tracked",
+            json={"company_name": "Intel"},
+            headers=_admin_header(),
+        )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["company_name"] == "Intel"
+        mock_db.add_tracked_company.assert_called_once_with("Intel")
+
+    def test_add_duplicate_returns_409(self, client, mock_db):
+        """Adding an already-tracked company returns 409."""
+        mock_db.add_tracked_company.return_value = None
+
+        response = client.post(
+            "/admin/tracked",
+            json={"company_name": "NVIDIA"},
+            headers=_admin_header(),
+        )
+
+        assert response.status_code == 409
+        assert "already tracked" in response.json()["detail"].lower()
+
+    def test_add_tracked_requires_admin(self, client, mock_db):
+        """Regular user cannot add tracked companies."""
+        mock_db.get_user_by_id.return_value = {
+            "id": 2,
+            "email": "user@test.com",
+            "role": "user",
+            "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.post(
+            "/admin/tracked",
+            json={"company_name": "Intel"},
+            headers=_user_header(),
+        )
+
+        assert response.status_code == 403
+
+    def test_add_tracked_empty_name_rejected(self, client):
+        """Empty company name is rejected by validation."""
+        response = client.post(
+            "/admin/tracked",
+            json={"company_name": ""},
+            headers=_admin_header(),
+        )
+
+        assert response.status_code == 422  # Pydantic validation error
+
+
+# ---------- DELETE /admin/tracked/{company_name} ----------
+
+class TestRemoveTrackedCompany:
+    """DELETE /admin/tracked/{company_name}"""
+
+    def test_remove_tracked_company_success(self, client, mock_db):
+        """Admin can remove a tracked company."""
+        mock_db.remove_tracked_company.return_value = True
+
+        response = client.delete(
+            "/admin/tracked/NVIDIA",
+            headers=_admin_header(),
+        )
+
+        assert response.status_code == 200
+        assert "Stopped tracking" in response.json()["message"]
+        mock_db.remove_tracked_company.assert_called_once_with("NVIDIA")
+
+    def test_remove_nonexistent_returns_404(self, client, mock_db):
+        """Removing a non-tracked company returns 404."""
+        mock_db.remove_tracked_company.return_value = False
+
+        response = client.delete(
+            "/admin/tracked/UnknownCorp",
+            headers=_admin_header(),
+        )
+
+        assert response.status_code == 404
+        assert "not found" in response.json()["detail"].lower()
+
+    def test_remove_tracked_requires_admin(self, client, mock_db):
+        """Regular user cannot remove tracked companies."""
+        mock_db.get_user_by_id.return_value = {
+            "id": 2,
+            "email": "user@test.com",
+            "role": "user",
+            "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.delete(
+            "/admin/tracked/NVIDIA",
+            headers=_user_header(),
+        )
+
+        assert response.status_code == 403
+
+
+# ---------- GET /admin/alerts ----------
+
+class TestListAlerts:
+    """GET /admin/alerts"""
+
+    def test_list_alerts_returns_data(self, client, mock_db):
+        """Admin can list alerts."""
+        mock_db.list_alerts.return_value = [
+            {
+                "id": 1,
+                "company_name": "NVIDIA",
+                "alert_type": "patent_count_change",
+                "message": "Patent count increased by 25%",
+                "created_at": "2025-06-15T10:00:00Z",
+            },
+        ]
+
+        response = client.get("/admin/alerts", headers=_admin_header())
+
+        assert response.status_code == 200
+        data = response.json()
+        assert len(data) == 1
+        assert data[0]["alert_type"] == "patent_count_change"
+
+    def test_list_alerts_with_limit(self, client, mock_db):
+        """Custom limit parameter is passed to the database."""
+        mock_db.list_alerts.return_value = []
+
+        response = client.get("/admin/alerts?limit=10", headers=_admin_header())
+
+        assert response.status_code == 200
+        mock_db.list_alerts.assert_called_once_with(limit=10)
+
+    def test_list_alerts_requires_admin(self, client, mock_db):
+        """Regular user cannot access alerts."""
+        mock_db.get_user_by_id.return_value = {
+            "id": 2,
+            "email": "user@test.com",
+            "role": "user",
+            "created_at": datetime(2025, 1, 1, tzinfo=timezone.utc),
+        }
+
+        response = client.get("/admin/alerts", headers=_user_header())
+
+        assert response.status_code == 403
+
+
+# ---------- Scheduler integration ----------
+
+class TestSchedulerIntegration:
+    """Tests for scheduler.run_scheduled_analysis()."""
+
+    def test_no_tracked_companies_skips_analysis(self):
+        """Scheduler does nothing when no companies are tracked."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = []
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer") as mock_analyzer_cls:
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        mock_analyzer_cls.assert_not_called()
+
+    def test_scheduler_analyzes_each_tracked_company(self):
+        """Scheduler runs analysis for every tracked company."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "NVIDIA", "last_patent_count": 100},
+            {"company_name": "AMD", "last_patent_count": 50},
+        ]
+
+        mock_result_nvidia = MagicMock(success=True, patent_count=110)
+        mock_result_amd = MagicMock(success=True, patent_count=55)
+        mock_analyzer = MagicMock()
+        mock_analyzer._analyze_company_safe.side_effect = [mock_result_nvidia, mock_result_amd]
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer", return_value=mock_analyzer):
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        assert mock_analyzer._analyze_company_safe.call_count == 2
+        mock_db.update_tracked_company.assert_any_call("NVIDIA", 110)
+        mock_db.update_tracked_company.assert_any_call("AMD", 55)
+
+    def test_scheduler_triggers_alert_on_significant_change(self):
+        """Scheduler stores an alert when patent count changes significantly."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "Tesla", "last_patent_count": 100},
+        ]
+
+        mock_result = MagicMock(success=True, patent_count=130)  # 30% increase
+        mock_analyzer = MagicMock()
+        mock_analyzer._analyze_company_safe.return_value = mock_result
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer", return_value=mock_analyzer):
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        mock_db.store_alert.assert_called_once()
+        alert_kwargs = mock_db.store_alert.call_args
+        assert alert_kwargs[1]["company_name"] == "Tesla"
+        assert alert_kwargs[1]["alert_type"] == "patent_count_change"
+        assert alert_kwargs[1]["old_value"] == 100
+        assert alert_kwargs[1]["new_value"] == 130
+
+    def test_scheduler_no_alert_for_small_change(self):
+        """Scheduler does not alert when change is below threshold."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "Intel", "last_patent_count": 100},
+        ]
+
+        mock_result = MagicMock(success=True, patent_count=105)  # 5% increase
+        mock_analyzer = MagicMock()
+        mock_analyzer._analyze_company_safe.return_value = mock_result
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer", return_value=mock_analyzer):
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        mock_db.store_alert.assert_not_called()
+
+    def test_scheduler_handles_analysis_failure(self):
+        """Scheduler continues when one company fails analysis."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "FailCo", "last_patent_count": 50},
+            {"company_name": "SuccessCo", "last_patent_count": 30},
+        ]
+
+        mock_fail_result = MagicMock(success=False, error="API timeout")
+        mock_ok_result = MagicMock(success=True, patent_count=35)
+        mock_analyzer = MagicMock()
+        mock_analyzer._analyze_company_safe.side_effect = [mock_fail_result, mock_ok_result]
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer", return_value=mock_analyzer):
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        # FailCo should not get updated, SuccessCo should
+        mock_db.update_tracked_company.assert_called_once_with("SuccessCo", 35)
+
+    def test_scheduler_handles_exception_in_analysis(self):
+        """Scheduler continues even when analysis raises an exception."""
+        mock_db = MagicMock()
+        mock_db.list_tracked_companies.return_value = [
+            {"company_name": "CrashCo", "last_patent_count": 10},
+            {"company_name": "OKCo", "last_patent_count": 20},
+        ]
+
+        mock_ok_result = MagicMock(success=True, patent_count=22)
+        mock_analyzer = MagicMock()
+        mock_analyzer._analyze_company_safe.side_effect = [
+            RuntimeError("unexpected error"),
+            mock_ok_result,
+        ]
+
+        with patch("SPARC.scheduler.get_db_client", return_value=mock_db), \
+             patch("SPARC.scheduler.CompanyAnalyzer", return_value=mock_analyzer):
+            from SPARC.scheduler import run_scheduled_analysis
+            run_scheduled_analysis()
+
+        # OKCo should still be processed
+        mock_db.update_tracked_company.assert_called_once_with("OKCo", 22)

tests/test_webhooks.py

@@ -0,0 +1,280 @@
+"""Tests for webhook notification system: retry logic and Slack/Discord payload format.
+
+Covers issue #1657:
+- Retry logic with exponential backoff in _send_with_retry
+- Slack/Discord payload formatting in _build_payload
+- Generic HTTP POST payload formatting
+- notify() dispatching to multiple URLs
+- notify_job_completed() and notify_alert() convenience helpers
+"""
+
+from datetime import datetime
+from unittest.mock import MagicMock, patch, call
+
+import pytest
+import requests
+
+from SPARC.webhooks import (
+    MAX_RETRIES,
+    _build_payload,
+    _is_slack_url,
+    _send_with_retry,
+    notify,
+    notify_alert,
+    notify_job_completed,
+)
+
+
+class TestIsSlackUrl:
+    """Tests for Slack/Discord URL detection."""
+
+    def test_slack_webhook_url(self):
+        assert _is_slack_url("https://hooks.slack.com/services/T00/B00/xxx") is True
+
+    def test_discord_webhook_url(self):
+        assert _is_slack_url("https://discord.com/api/webhooks/123/abc") is True
+
+    def test_generic_url(self):
+        assert _is_slack_url("https://example.com/webhook") is False
+
+    def test_empty_url(self):
+        assert _is_slack_url("") is False
+
+
+class TestBuildPayload:
+    """Tests for payload construction."""
+
+    def test_generic_payload_structure(self):
+        """Generic payload includes event type, timestamp, and data."""
+        payload = _build_payload("job_completed", {"job_id": "abc123"})
+
+        assert payload["event"] == "job_completed"
+        assert payload["job_id"] == "abc123"
+        assert "timestamp" in payload
+        # Timestamp should be ISO format ending with Z
+        assert payload["timestamp"].endswith("Z")
+
+    def test_slack_payload_wraps_in_text(self):
+        """Slack payload wraps content in a 'text' field."""
+        payload = _build_payload("patent_alert", {"company_name": "NVIDIA"}, slack=True)
+
+        assert "text" in payload
+        assert "patent_alert" in payload["text"]
+        assert "NVIDIA" in payload["text"]
+        # Slack payload should NOT have the event/timestamp at top level
+        assert "event" not in payload
+        assert "timestamp" not in payload
+
+    def test_generic_payload_does_not_have_text_field(self):
+        """Non-Slack payload does not wrap in text."""
+        payload = _build_payload("job_completed", {"status": "done"})
+
+        assert "text" not in payload
+        assert payload["status"] == "done"
+
+    def test_slack_payload_contains_bold_header(self):
+        """Slack payload starts with bold event header using Slack markdown."""
+        payload = _build_payload("job_completed", {"count": 5}, slack=True)
+
+        assert payload["text"].startswith("*[SPARC] job_completed*")
+
+    def test_payload_merges_all_data_keys(self):
+        """All data keys are included in the generic payload."""
+        data = {"key1": "val1", "key2": 42, "key3": True}
+        payload = _build_payload("test_event", data)
+
+        assert payload["key1"] == "val1"
+        assert payload["key2"] == 42
+        assert payload["key3"] is True
+
+
+class TestSendWithRetry:
+    """Tests for retry logic in _send_with_retry."""
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_success_on_first_attempt(self, mock_post, mock_sleep):
+        """Successful delivery on first attempt, no retries."""
+        mock_post.return_value = MagicMock(status_code=200)
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is True
+        mock_post.assert_called_once()
+        mock_sleep.assert_not_called()
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_success_on_second_attempt(self, mock_post, mock_sleep):
+        """Fails first, succeeds on retry."""
+        mock_post.side_effect = [
+            MagicMock(status_code=500),
+            MagicMock(status_code=200),
+        ]
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is True
+        assert mock_post.call_count == 2
+        mock_sleep.assert_called_once()
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_all_retries_exhausted(self, mock_post, mock_sleep):
+        """Returns False after all retries fail."""
+        mock_post.return_value = MagicMock(status_code=500)
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is False
+        assert mock_post.call_count == MAX_RETRIES
+        assert mock_sleep.call_count == MAX_RETRIES - 1
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_exponential_backoff_timing(self, mock_post, mock_sleep):
+        """Backoff wait times follow exponential pattern (2^attempt)."""
+        mock_post.return_value = MagicMock(status_code=500)
+
+        _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        # With BACKOFF_BASE=2: attempt 1 -> sleep(2), attempt 2 -> sleep(4)
+        expected_waits = [call(2 ** i) for i in range(1, MAX_RETRIES)]
+        assert mock_sleep.call_args_list == expected_waits
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_network_error_triggers_retry(self, mock_post, mock_sleep):
+        """Network exceptions trigger retry, not immediate failure."""
+        mock_post.side_effect = [
+            requests.ConnectionError("Connection refused"),
+            MagicMock(status_code=200),
+        ]
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is True
+        assert mock_post.call_count == 2
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_timeout_error_triggers_retry(self, mock_post, mock_sleep):
+        """Timeout exceptions trigger retry."""
+        mock_post.side_effect = [
+            requests.Timeout("Request timed out"),
+            MagicMock(status_code=200),
+        ]
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is True
+        assert mock_post.call_count == 2
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_2xx_status_codes_accepted(self, mock_post, mock_sleep):
+        """Any 2xx status code is treated as success."""
+        mock_post.return_value = MagicMock(status_code=204)
+
+        result = _send_with_retry("https://example.com/hook", {"event": "test"})
+
+        assert result is True
+        mock_post.assert_called_once()
+
+    @patch("SPARC.webhooks.time.sleep")
+    @patch("SPARC.webhooks.requests.post")
+    def test_posts_json_payload(self, mock_post, mock_sleep):
+        """Payload is sent as JSON with correct timeout."""
+        mock_post.return_value = MagicMock(status_code=200)
+        payload = {"event": "test", "data": "value"}
+
+        _send_with_retry("https://example.com/hook", payload)
+
+        mock_post.assert_called_once_with(
+            "https://example.com/hook", json=payload, timeout=10
+        )
+
+
+class TestNotify:
+    """Tests for the notify() dispatcher."""
+
+    @patch("SPARC.webhooks._send_with_retry")
+    @patch("SPARC.webhooks.WEBHOOK_URLS", ["https://example.com/hook1", "https://example.com/hook2"])
+    def test_dispatches_to_all_urls(self, mock_send):
+        """notify() sends to every configured webhook URL."""
+        mock_send.return_value = True
+
+        notify("job_completed", {"job_id": "test123"})
+
+        assert mock_send.call_count == 2
+
+    @patch("SPARC.webhooks._send_with_retry")
+    @patch("SPARC.webhooks.WEBHOOK_URLS", [])
+    def test_no_urls_configured_returns_immediately(self, mock_send):
+        """No-op when no webhook URLs are configured."""
+        notify("job_completed", {"job_id": "test123"})
+
+        mock_send.assert_not_called()
+
+    @patch("SPARC.webhooks._send_with_retry")
+    @patch("SPARC.webhooks.WEBHOOK_URLS", [
+        "https://hooks.slack.com/services/T00/B00/xxx",
+        "https://example.com/generic",
+    ])
+    def test_slack_url_gets_slack_payload(self, mock_send):
+        """Slack URLs receive Slack-formatted payloads, others get generic."""
+        mock_send.return_value = True
+
+        notify("test_event", {"key": "val"})
+
+        # First call (Slack URL) should have "text" key
+        slack_payload = mock_send.call_args_list[0][0][1]
+        assert "text" in slack_payload
+
+        # Second call (generic URL) should have "event" key
+        generic_payload = mock_send.call_args_list[1][0][1]
+        assert "event" in generic_payload
+        assert generic_payload["event"] == "test_event"
+
+
+class TestNotifyJobCompleted:
+    """Tests for notify_job_completed() convenience function."""
+
+    @patch("SPARC.webhooks.notify")
+    def test_sends_correct_event_and_data(self, mock_notify):
+        """Job completion sends proper event type and summary."""
+        notify_job_completed(
+            job_id="batch-001",
+            status="completed",
+            total_companies=10,
+            successful=8,
+            failed=2,
+        )
+
+        mock_notify.assert_called_once()
+        event, data = mock_notify.call_args[0]
+        assert event == "job_completed"
+        assert data["job_id"] == "batch-001"
+        assert data["successful"] == 8
+        assert data["failed"] == 2
+        assert "8/10" in data["summary"]
+
+
+class TestNotifyAlert:
+    """Tests for notify_alert() convenience function."""
+
+    @patch("SPARC.webhooks.notify")
+    def test_sends_correct_event_and_data(self, mock_notify):
+        """Alert notification sends patent_alert event type."""
+        notify_alert(
+            company_name="NVIDIA",
+            alert_type="patent_count_change",
+            message="Patent count increased by 30%",
+        )
+
+        mock_notify.assert_called_once()
+        event, data = mock_notify.call_args[0]
+        assert event == "patent_alert"
+        assert data["company_name"] == "NVIDIA"
+        assert data["alert_type"] == "patent_count_change"
+        assert "30%" in data["message"]