2026-09-26 channel robustness (audit)

The library

Rendered from docs/specs/2026-09-26_channel-robustness-audit.md; the markdown file is the record.

Dimension	Grade	Notes
Plan adherence	Excellent	Amended design implemented; deviations recorded. Reproduced λ̂, its interval, codec verdict, and all saved E readouts.
Scope discipline	Excellent	Diagnostic scripts, tests, and documentation only; protected scoring and training paths unchanged.
Test coverage	Acceptable	Spec records 584 passing. Independently obtained 118 targeted passes, including all 52 documentation tests; sandbox restrictions prevented complete verification.
Review compliance	Excellent	Recorded findings addressed, including error-only caches returning “inconclusive.”
Freeze integrity	Acceptable	Skipped: no P1/P2/P3 hashes supplied.
Regression check	Acceptable	No change-induced regression identified. Changed files lint clean; repository-wide lint retains three unrelated findings. No TSV required under the explicit diagnostic disposition.
Documentation	Acceptable	Required deliverables and disclosure present; minor codec-summary wording inconsistency.
Overall	Acceptable

Documentation — downgrade to Acceptable. The report calls Kaiser the “closest reproduction,” although AAC + Kaiser has the smaller distance (1.045 versus 1.081). Say “no codec satisfies D5” instead. The table and gating decision are correct, so this does not change the reader’s action or warrant Fail.
Test coverage / Regression check — verification limited to Acceptable. The read-only sandbox blocked uv cache initialization. Direct virtualenv execution yielded 118 passes, seven failures from cache/temporary-file restrictions, and one temporary-directory setup error. These are environmental failures, not demonstrated regressions; the recorded 584-pass full-suite result was not independently reproduced.
Regression check — no additional downgrade. Repository-wide Ruff reports the three documented findings in src/hearsay/analyzer.py, introduced by unrelated commit 19925a3. Ruff passes on all four changed Python files.