FUXA failed every hunt with HTTP 400, and neither run could say why. The client
discarded the response body. With the body shown, the reason was "This model's
maximum context length...": FUXA ships minified bundles whose single lines run to
megabytes, and grep_repo returned a matched line whole.
- grep_repo and find_refs quote a matched line (240 characters), never the whole
line.
- Every tool result is capped at 16 x max_chars, with a truncation marker.
- OpenRouterChatClient errors carry the provider's response body (first 500
characters). That would also have exposed the rejected model id in one call
instead of eighteen days.
After the fix, FUXA candidates verify normally at $0.004-0.013 each. A test covers
the megabyte-line case.
verify_sinks.py: skip futures cancelled at the spend ceiling instead of reading
them (the run crashed with CancelledError).
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
Each grep_repo and find_refs call re-enumerated the tree (walk, ignore rules,
vendored checks) and re-read every file. The v2 sink verifier spent almost three
hours on its first case (pgAdmin, about 1,800 files) at 108% CPU with one open
connection. It was CPU-bound in these tools, not waiting on the model.
Source lines are now memoised per root, keyed by path and modification time. A hit
is re-validated file by file, because an edit inside a subdirectory does not touch
the root's mtime; a test covers one enumeration and a detected edit.
verify_sinks.py now runs candidates in worker processes, not threads, and appends
each candidate's result to a per-case log, so a stopped run resumes where it left
off. GoPay: 12 candidates in 14 s, the real site found.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
Per candidate function, one bounded tool-hunter pass (custom prompt, the file as
context, 3 steps) asks whether attacker-controlled data reaches the operation
without a sufficient guard. It reports only with a stated source-to-sink path.
Hard spend ceiling, parallel workers; one run per pin; the fixed pin is rechecked
only for detected sites. Exploratory on v2.
Pilot: on GoPay, the one real site was reported in 3 of 4 runs and nothing else
out of 12 candidates.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
