Splits pull+transcribe (now tower-side, eager) from extract+embed
(stays on the dev scheduler). Three machine-coordination pieces land
together because they reference each other:
- v3 migration adds sources.claimed_by + claimed_at — observability +
stale-claim recovery columns. The actual race-safety primitive is
`SELECT ... FOR UPDATE SKIP LOCKED` in the new claim helper, so two
machines can poll the queue without doubling work.
- src/second_brain/claim.py owns the claim dance (claim_next_source,
release_claim, reap_stale_claims). Both stage gates filter by
source_type so the tower never grabs articles and the dev side never
grabs videos.
- src/second_brain/transcribe.py wraps faster-whisper (lazy-imported so
it stays out of the dev install). resolve_settings() reads env >
[whisper] block > defaults, falling back to int8 on cpu / float16 on
cuda when compute_type is unspecified. Default model large-v3.
- src/second_brain/scheduler/transcribe_worker.py is the long-running
poll loop. Reads pipeline_settings every iteration so the dashboard's
enable/window/max-items/max-video-length take effect within one
cycle. Reaps stale claims at startup. SIGTERM-clean. DB-unreachable
backs off with a log line; never crash-loops.
- adapters/youtube.py drops the torch-whisper transcribe path; pull
stays. Removes openai-whisper from the default deps and gates
faster-whisper behind a new `tower` extra (uv sync --extra tower).
- main.py: new `second-brain transcribe-worker` (--once for ad-hoc).
`process` now article-only on the pull side but still picks up
TRANSCRIBED of any source_type for the extract step.
Live-verified: migration applies clean, transcribe-worker --once
honors transcription_enabled=false gate.
Ruff autofix removed pre-existing F401 unused imports across adapters,
context, compiler, extractor, scheduler, web, and main. Also reordered
models.py so its SQLAlchemy imports sit at the top of the file
(E402 was triggered by the inline `utcnow` helper definition).
Added a [dependency-groups] dev block (pytest, pytest-cov, ruff) so the
zero-check test gauntlet — which runs `pytest --cov --cov-report=term-missing`
— can resolve its plugins without a manual `uv pip install pytest-cov`.
