[k3scat]

With key_concurrency: false a key is locked for the duration of a request, and nothing ever expired that lock. Any path that failed to release one took the credential out of rotation for the lifetime of the process; once every key had leaked, the API stopped serving entirely and stayed that way.

The reported symptom was a queue stuck for 30 minutes logging a wait that never changed:

DEBUG | nya.core.queue - Resource Unavailable for novelai endpoint - wait time: 0.50s

That constant is diagnostic. time_to_key_ready treats a locked key as inf, and falls through to a hardcoded return 1.0 when every key is inf, which the queue halves to 0.50s. A rate-limit wait would count down; only an all-locked pool produces a fixed value forever.

Make the lock a deadline rather than a flag. locked becomes a property that expires on its own, so every existing reader — is_limited, _key_is_unavailable, time_to_key_ready — picks up the recovery with no change. The ceiling is twice the API's request timeout, floored at 60s: generous on purpose, because releasing a key still in use would put two requests on one credential, which is the thing key_concurrency: false exists to prevent, and a streamed response can outlive the request timeout since that bounds only the upstream call. An expiry logs a warning: it means a release was missed, which is a bug worth seeing rather than silently absorbing.

Also stop watchfiles logging every filesystem event at INFO. Uvicorn's reloader watches the working directory, which is where log_file usually lives, so writing a log line produced an event that logged a line — a feedback loop visible in the same report as "1 change detected" every 350ms. That was a regression from routing the standard library through the shared handler, which put those records into the log file for the first time.

Verified by mutation: with the expiry removed, both new tests fail with exactly the production signature — time_to_key_ready pinned at 1.0.

[codecov]

Codecov Report

❌ Patch coverage is 90.00000% with 3 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
nya/core/control.py	70.00%	3 Missing ⚠️

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