fix(login): confirm via credentials file + validate the OAuth URL

Testing showed the wide-window fix captured the full URL, but login still
failed at submit ("login not confirmed"): the old check snapshotted the pane
once after 3s and only matched a few success strings, so an in-progress or
differently-worded exchange read as failure. Two hardening changes:

- login_submit now polls (up to 40s) and confirms by the authoritative signal —
  claude's credentials file changing on disk (any of the known locations /
  ~/.claude/*credential*) — with success-text and clean-exit as fallbacks.
- login_start captures with escape sequences (-e) and accepts only a *complete*
  OAuth URL (https:// + client_id + redirect_uri + state). This recovers the
  real href when claude renders the link as an OSC-8 hyperlink (whose visible
  text can be garbled, e.g. the "ttps://claude.com/cai/..." seen in testing) and
  refuses partial/garbled captures. On timeout the error now includes the actual
  last screen so a wrong menu/onboarding state is diagnosable.

tmux.capture_pane gains an `escapes` flag. Tests cover URL completeness,
OSC-8 href recovery, and credentials-file confirmation. Suite green (199).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YKVyBmKvWDVgrFC9WER2f2

src/handler/control/login.py

@@ -9,7 +9,8 @@ handoff:
    the pane for the ``claude.com`` / ``claude.ai`` authorization URL. The URL is returned
    to the UI (which opens it in an iframe) and the tmux session is *left alive*.
 2. ``login_submit`` sends the authorization code the operator pastes back into that same
-   still-alive session, waits for claude to exchange it, and reports success.
+   still-alive session, then confirms the login by watching for claude to write its
+   credentials file (with a success-text fallback).
 
 Everything shells out through the :mod:`~handler.control.tmux` seam, so the whole flow is
 unit-testable with a fake tmux and never needs a real ``claude`` binary — the same pattern
@@ -22,6 +23,7 @@ onboarding (theme/trust prompts) before the ``/login`` menu, bump ``boot_wait``.
 
 from __future__ import annotations
 
+import glob
 import os
 import re
 import time
@@ -38,18 +40,23 @@ LOGIN_SESSION = "handler__login"
 LOGIN_COLS = 500
 LOGIN_ROWS = 50
 
-# Any http(s) URL in the pane; we then prefer the OAuth/authorize link among them. The
-# character class stops at whitespace, quotes, and — importantly — box-drawing glyphs
-# (U+2500–U+257F) the TUI may render flush against the link, so a bordered URL isn't
-# captured with a trailing "│".
-_URL_RE = re.compile(r"https?://[^\s\"'<>`|─-╿]+")
-_OAUTH_HINTS = ("oauth", "authorize", "claude.ai", "claude.com", "console.anthropic")
+# Strip ANSI CSI + OSC escape sequences so success-text matching sees plain text.
+_ANSI_RE = re.compile(
+    r"\x1b\[[0-9;?]*[ -/]*[@-~]"  # CSI (colors, cursor moves)
+    r"|\x1b\][^\x07\x1b]*(?:\x07|\x1b\\)"  # OSC (…terminated by BEL or ST)
+    r"|\x1b[@-Z\\-_]"  # two-char escapes
+)
+# An http(s) URL. The class excludes whitespace, quotes, box-drawing glyphs the TUI may
+# render flush against the link, *and* control/escape bytes — so a URL sitting inside an
+# OSC-8 hyperlink escape (``\x1b]8;;<URL>\x1b\\``) is recovered cleanly, cut at the ESC.
+_URL_RE = re.compile(r"https?://[^\s\"'<>`|\x00-\x1f─-╿]+")
 _SUCCESS_HINTS = (
     "login successful",
     "logged in",
     "successfully authenticated",
     "authentication successful",
     "you are now logged in",
+    "welcome back",
 )
 
 
@@ -66,28 +73,76 @@ def _sleep(seconds: float) -> None:
     time.sleep(seconds)
 
 
+def _strip_ansi(text: str) -> str:
+    return _ANSI_RE.sub("", text or "")
+
+
+def _is_complete_oauth_url(url: str) -> bool:
+    """A *usable* Claude OAuth URL, not a partial/garbled capture.
+
+    Requiring the scheme + the OAuth query markers rejects a mid-render capture like
+    ``ttps://claude.com/cai/oauth?…`` (dropped scheme chars) or a URL cut before its
+    query string — handing either to the iframe would send the operator to a broken page.
+    """
+    low = url.lower()
+    return (
+        low.startswith("https://")
+        and "oauth" in low
+        and "client_id=" in low
+        and "redirect_uri=" in low
+        and "state=" in low
+    )
+
+
 def _extract_url(pane: str) -> str | None:
-    """Pull the login URL out of a captured pane, preferring the OAuth link."""
+    """Return the first *complete* OAuth URL found in a captured pane, else ``None``."""
     if not pane:
         return None
-    candidates = [c.rstrip(".,);]") for c in _URL_RE.findall(pane)]
-    for c in candidates:
-        if any(hint in c.lower() for hint in _OAUTH_HINTS):
-            return c
-    return candidates[0] if candidates else None
+    for raw in _URL_RE.findall(pane):
+        candidate = raw.rstrip(".,);]}>")
+        if _is_complete_oauth_url(candidate):
+            return candidate
+    return None
+
+
+def _credentials_fingerprint() -> tuple:
+    """A fingerprint of claude's on-disk credentials, to detect a login writing them.
+
+    Claude Code stores its OAuth credentials under the user's home; the exact filename has
+    drifted across versions, so we watch every likely location and any ``*credential*``
+    file under ``~/.claude``. The fingerprint is ``(path, mtime, size)`` tuples — it
+    changes when a login creates or rewrites the credentials, which is a far more reliable
+    "did it work" signal than scraping the TUI for a success string.
+    """
+    home = _home()
+    paths = {
+        os.path.join(home, ".claude", ".credentials.json"),
+        os.path.join(home, ".claude", "credentials.json"),
+        os.path.join(home, ".claude.json"),
+        os.path.join(home, ".config", "claude", "credentials.json"),
+    }
+    paths.update(glob.glob(os.path.join(home, ".claude", "*credential*")))
+    fp = []
+    for p in sorted(paths):
+        try:
+            st = os.stat(p)
+            fp.append((p, st.st_mtime_ns, st.st_size))
+        except OSError:
+            continue
+    return tuple(fp)
 
 
 def start(
     *,
-    boot_wait: float = 4.0,
-    menu_wait: float = 1.5,
-    url_timeout: float = 30.0,
+    boot_wait: float = 6.0,
+    menu_wait: float = 2.0,
+    url_timeout: float = 45.0,
     poll_interval: float = 0.5,
 ) -> dict:
     """Open ``claude`` in tmux, drive ``/login`` to the subscription account, return the URL.
 
     Leaves the tmux session alive for :func:`submit_code`. Raises :class:`LoginError` if
-    no authorization URL appears within ``url_timeout`` seconds.
+    no complete authorization URL appears within ``url_timeout`` seconds.
     """
     claude = get_settings().claude_bin
     # A stale session from a previous, abandoned attempt would swallow our keystrokes.
@@ -97,7 +152,7 @@ def start(
     tmux.new_session(
         LOGIN_SESSION, cwd=_home(), command=claude, env={}, width=LOGIN_COLS, height=LOGIN_ROWS
     )
-    _sleep(boot_wait)  # let claude boot to its prompt
+    _sleep(boot_wait)  # let claude finish its splash/boot and reach a prompt
 
     tmux.send_keys(LOGIN_SESSION, "/login")
     _sleep(menu_wait)
@@ -108,26 +163,43 @@ def start(
 
     deadline = time.monotonic() + url_timeout
     url: str | None = None
+    last_pane = ""
     while url is None and time.monotonic() < deadline:
-        url = _extract_url(tmux.capture_pane(LOGIN_SESSION))
+        # Capture with escapes so an OSC-8 hyperlink href is recoverable; require a
+        # *complete* URL so a still-rendering pane keeps us polling instead of returning
+        # a garbled fragment.
+        last_pane = tmux.capture_pane(LOGIN_SESSION, escapes=True)
+        url = _extract_url(last_pane)
         if url is None:
             _sleep(poll_interval)
     if url is None:
-        # Don't leave a half-driven session lying around on failure.
+        # Don't leave a half-driven session lying around on failure. Surface what claude
+        # actually rendered so a wrong menu/onboarding state is diagnosable, not opaque.
+        tail = _tail(_strip_ansi(last_pane))
         if tmux.has_session(LOGIN_SESSION):
             tmux.kill_session(LOGIN_SESSION)
-        raise LoginError(
-            "timed out waiting for the claude login URL — is the 'claude' binary installed "
-            "in the control container and does '/login' open the subscription flow?"
+        message = (
+            "timed out waiting for a complete claude login URL — is the 'claude' binary "
+            "installed in the control container and does '/login' open the subscription flow?"
         )
+        if tail:
+            message += f" Last screen:\n{tail}"
+        raise LoginError(message)
     return {"session": LOGIN_SESSION, "url": url}
 
 
-def submit_code(code: str, *, settle_wait: float = 3.0) -> dict:
-    """Feed the pasted authorization ``code`` into the live login session.
+def submit_code(
+    code: str,
+    *,
+    poll_timeout: float = 40.0,
+    poll_interval: float = 1.0,
+) -> dict:
+    """Feed the pasted authorization ``code`` into the live login session and confirm.
 
-    Returns ``{"success": bool, "output": <pane tail>}``. Kills the session on success.
-    Raises :class:`LoginError` if there is no active login session to submit to.
+    Confirms by polling (up to ``poll_timeout`` seconds) for any of: claude's credentials
+    file changing on disk (the authoritative signal), a success line in the pane, or the
+    session exiting cleanly. Returns ``{"success": bool, "output": <pane tail>}`` and kills
+    the session on success. Raises :class:`LoginError` if there is no session to submit to.
     """
     code = (code or "").strip()
     if not code:
@@ -135,14 +207,29 @@ def submit_code(code: str, *, settle_wait: float = 3.0) -> dict:
     if not tmux.has_session(LOGIN_SESSION):
         raise LoginError("no active claude login session — start the login flow again")
 
+    baseline = _credentials_fingerprint()
     tmux.send_keys(LOGIN_SESSION, code)
-    _sleep(settle_wait)
 
-    pane = tmux.capture_pane(LOGIN_SESSION)
-    success = _looks_successful(pane)
+    deadline = time.monotonic() + poll_timeout
+    success = False
+    pane = ""
+    while time.monotonic() < deadline:
+        _sleep(poll_interval)
+        pane = tmux.capture_pane(LOGIN_SESSION, escapes=True)
+        if _credentials_fingerprint() != baseline:
+            success = True
+            break
+        if _looks_successful(_strip_ansi(pane)):
+            success = True
+            break
+        if not tmux.has_session(LOGIN_SESSION):
+            # claude exited on its own after a successful login.
+            success = True
+            break
+
     if success and tmux.has_session(LOGIN_SESSION):
         tmux.kill_session(LOGIN_SESSION)
-    return {"success": success, "output": _tail(pane)}
+    return {"success": success, "output": _tail(_strip_ansi(pane))}
 
 
 def _looks_successful(pane: str) -> bool:

src/handler/control/tmux.py

@@ -80,19 +80,21 @@ def send_keys(name: str, keys: str) -> None:
     subprocess.run([tmux, "send-keys", "-t", name, keys, "Enter"], check=True)
 
 
-def capture_pane(name: str) -> str:
+def capture_pane(name: str, escapes: bool = False) -> str:
     """Return the visible text of a session's pane.
 
     ``-p`` prints to stdout, ``-J`` joins wrapped lines so a long URL split across the
     pane width comes back on one logical line (the login flow relies on this to recover
-    the claude.com authorization link). Returns an empty string if the session is gone.
+    the claude.com authorization link). ``escapes=True`` adds ``-e`` to keep ANSI/OSC
+    escape sequences — the login URL extractor uses this so it can also recover a URL that
+    the TUI renders as an OSC-8 hyperlink (where the visible text differs from the href).
+    Returns an empty string if the session is gone.
     """
     tmux = get_settings().tmux_bin
-    result = subprocess.run(
-        [tmux, "capture-pane", "-t", name, "-p", "-J"],
-        capture_output=True,
-        text=True,
-    )
+    argv = [tmux, "capture-pane", "-t", name, "-p", "-J"]
+    if escapes:
+        argv.append("-e")
+    result = subprocess.run(argv, capture_output=True, text=True)
     if result.returncode != 0:
         return ""
     return result.stdout

tests/test_control_login.py

@@ -1,8 +1,9 @@
-"""The claude web-login seam: driving ``claude /login`` through tmux and scraping the URL.
+"""The claude web-login seam: driving ``claude /login`` through tmux, scraping the URL,
+and confirming the login.
 
 Uses the shared ``fake_tmux`` fixture (extended here with a scripted ``capture_pane``) and
-patches out the real sleeps, so no live claude/tmux is touched — the same approach as the
-spawn tests.
+patches out the real sleeps + the on-disk credentials check, so no live claude/tmux/FS is
+touched — the same approach as the spawn tests.
 """
 
 from __future__ import annotations
@@ -17,20 +18,32 @@ def no_sleep(monkeypatch):
     monkeypatch.setattr(login, "_sleep", lambda *_a, **_k: None)
 
 
+@pytest.fixture
+def stable_creds(monkeypatch):
+    """No credentials change on disk — success must come from the pane/session signals."""
+    monkeypatch.setattr(login, "_credentials_fingerprint", lambda: ())
+
+
 def _pane(monkeypatch, *frames):
     """Make ``capture_pane`` return each frame in turn, then repeat the last one."""
     seq = list(frames)
 
-    def capture(_name):
+    def capture(_name, escapes=False):
         return seq[0] if len(seq) == 1 else seq.pop(0)
 
     monkeypatch.setattr(tmux, "capture_pane", capture)
 
 
-AUTH_URL = "https://claude.ai/oauth/authorize?code=true&client_id=abc&state=xyz"
+# A complete Claude OAuth URL (scheme + client_id + redirect_uri + state) — extraction
+# deliberately rejects anything less, so the fixtures must use the real shape.
+AUTH_URL = (
+    "https://claude.ai/oauth/authorize?code=true&client_id=abc123&response_type=code"
+    "&redirect_uri=https%3A%2F%2Fplatform.claude.com%2Foauth%2Fcode%2Fcallback"
+    "&scope=user%3Aprofile&code_challenge=chal&code_challenge_method=S256&state=st42"
+)
 
 
-def test_extract_url_prefers_oauth_link():
+def test_extract_url_prefers_complete_oauth_link():
     pane = f"Visit https://example.com/help or\n{AUTH_URL}\nand paste the code."
     assert login._extract_url(pane) == AUTH_URL
 
@@ -43,22 +56,24 @@ def test_extract_url_none_when_no_link():
     assert login._extract_url("no link here") is None
 
 
+def test_extract_url_rejects_incomplete_url():
+    # A garbled/partial capture (dropped scheme char, or no query string) must be refused
+    # so the iframe never opens a broken page.
+    assert login._extract_url("ttps://claude.com/cai/oauth/authorize?client_id=x") is None
+    assert login._extract_url("https://claude.ai/oauth/authorize") is None
+
+
 def test_extract_url_stops_at_box_border():
     # claude may draw the URL inside a rounded box; a "│" flush against the link must not
     # be captured as part of the URL.
     assert login._extract_url(f"│{AUTH_URL}│") == AUTH_URL
 
 
-def test_extract_url_captures_full_long_url_with_redirect_uri():
-    # The real login URL carries redirect_uri + PKCE; on a wide pane it arrives intact and
-    # extraction must not clip it (the truncation-at-80-cols bug was in capture, not here).
-    long_url = (
-        "https://claude.ai/oauth/authorize?code=true&client_id=9d1c250a-e61b-44d9-88ab-"
-        "0123456789ab&response_type=code&redirect_uri=https%3A%2F%2Fconsole.anthropic.com"
-        "%2Foauth%2Fcode%2Fcallback&scope=org%3Acreate_api_key+user%3Aprofile&"
-        "code_challenge=abcDEF123&code_challenge_method=S256&state=xyz789"
-    )
-    assert login._extract_url(f"Use this URL to sign in:\n{long_url}") == long_url
+def test_extract_url_recovers_href_from_osc8_hyperlink():
+    # claude renders the URL as an OSC-8 hyperlink: the visible text can be styled/garbled
+    # while the real href sits in the escape. Capturing with escapes lets us recover it.
+    pane = f"\x1b]8;;{AUTH_URL}\x1b\\click here\x1b]8;;\x1b\\"
+    assert login._extract_url(pane) == AUTH_URL
 
 
 def test_start_launches_claude_selects_subscription_and_returns_url(
@@ -103,11 +118,11 @@ def test_start_times_out_and_cleans_up_when_no_url(env, fake_tmux, no_sleep, mon
     assert login.LOGIN_SESSION not in fake_tmux["live"]
 
 
-def test_submit_code_sends_code_and_reports_success(env, fake_tmux, no_sleep, monkeypatch):
+def test_submit_code_confirmed_by_success_text(env, fake_tmux, no_sleep, stable_creds, monkeypatch):
     fake_tmux["live"].add(login.LOGIN_SESSION)
     _pane(monkeypatch, "Login successful. Welcome back!")
 
-    result = login.submit_code("my-auth-code")
+    result = login.submit_code("my-auth-code", poll_timeout=1.0)
 
     assert result["success"] is True
     assert "Login successful" in result["output"]
@@ -116,13 +131,32 @@ def test_submit_code_sends_code_and_reports_success(env, fake_tmux, no_sleep, mo
     assert login.LOGIN_SESSION not in fake_tmux["live"]
 
 
+def test_submit_code_confirmed_by_credentials_file(env, fake_tmux, no_sleep, monkeypatch):
+    fake_tmux["live"].add(login.LOGIN_SESSION)
+    # The pane never prints a success string, but claude writes its credentials — the
+    # authoritative signal. First call = baseline, later calls = changed.
+    calls = {"n": 0}
+
+    def fingerprint():
+        calls["n"] += 1
+        return () if calls["n"] == 1 else (("~/.claude/.credentials.json", 123, 45),)
+
+    monkeypatch.setattr(login, "_credentials_fingerprint", fingerprint)
+    _pane(monkeypatch, "still on the paste-code screen, no success text")
+
+    result = login.submit_code("code", poll_timeout=1.0)
+
+    assert result["success"] is True
+    assert login.LOGIN_SESSION not in fake_tmux["live"]
+
+
 def test_submit_code_reports_failure_without_killing_session(
-    env, fake_tmux, no_sleep, monkeypatch
+    env, fake_tmux, no_sleep, stable_creds, monkeypatch
 ):
     fake_tmux["live"].add(login.LOGIN_SESSION)
     _pane(monkeypatch, "Invalid code, please try again")
 
-    result = login.submit_code("wrong")
+    result = login.submit_code("wrong", poll_timeout=0.05)
 
     assert result["success"] is False
     assert login.LOGIN_SESSION in fake_tmux["live"]  # left up for a retry