HKV now flags hooks that build hookSpecificOutput.additionalContext from
un-grepped command output as an INFO advisory (weight 0, never severity-bearing
— excluded from the self-audit nonInfo set). That field enters Claude's context
every time the hook fires (plain stdout on exit 0 does not), so an unfiltered
payload is a recurring per-turn token cost.
- New lib scanners/lib/hook-additional-context.mjs: pure assessHookAdditionalContext
(unit-tested, no IO) + IO wrapper assessHookContextForRepo (walk hooks->scripts).
Heuristic: additionalContext + verbose-prone capture (cat/git log/execSync/…) &&
no filter (grep/head/jq/.slice). Deliberately low precision -> advisory only.
- HKV: emits the advisory inline on scripts it already reads (after the M5 verbose
check). Additive, info severity -> frozen v5.0.0 + SC-5 snapshots untouched.
- feature-gap: new filterHookLeverFinding companion, fires ONLY when >=1 chatty
hook is detected — surfaces the filter-before-Claude-reads lever (CC
filter-test-output.sh). Silent otherwise (opportunity, not noise).
- docs: README HKV + GAP scanner rows; scanner-internals.md HKV row + full B5
implementation note. CLAUDE.md kept lean ([skip-docs]); B5 fully documented in
README + scanner-internals.
Mechanism verified 2026-06-23 against code.claude.com/docs context-window.md
(additionalContext enters context; plain stdout does not). Suite 1239 -> 1254 green.
Version/badges/CHANGELOG wait for the v5.10 release cut.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Kjell Tore Guttormsen
d2c45a3bb8