New CPS scanner walks CLAUDE.md cascade and flags volatile content
between lines 31 and 150 — the cache-prefix window beyond TOK Pattern
A's top-30 territory. Volatile content anywhere in the cached prefix
forces a fresh cache write from that line down on every turn.
Volatile-pattern set extends TOK Pattern A with:
- shell-exec lines (! prefix) — common in CLAUDE.md to inject git/date
- ${VAR} substitutions — vary per-shell, defeat cache reuse
Severity: medium per finding. Skips lines 1-30 to avoid duplicating
Pattern A's range; CPS' value is in the 31-150 zone.
Wired into scan-orchestrator + scoring SCANNER_AREA_MAP. CPS shares
the "Token Efficiency" area with TOK; scoreByArea now deduplicates by
area name and combines counts across scanners contributing to the
same area, so the 9-area scorecard contract holds.
Fixtures volatile-mid-section/{volatile-line-60, volatile-line-200}
verify both positive (line 60) and out-of-window (line 200) cases.
[skip-docs] reason: v5 plan fences off README/CLAUDE.md badge updates
to Session 5; Forgejo pre-commit-docs-gate hook requires this tag.
Tests: 604 → 611 (+7).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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