The input-path duty `8deca93` scoped. All 83 lexicon patterns measured arm by
arm; two are quadratic, same shape 0.3.2 fixed -- a run in front of a required
literal that may cross the pattern's own opening anchor. Exponent 1.98 over five
points, so quadratic, not exponential.
markdown:link-anchor-injection `[` 1.91s @8k ~8.3h at the cap
markdown:link-anchor-injection `[system](` 0.006s @8k ~89s at the cap
markdown:link-ref-comment `[//]: # (` 0.22s @8k ~1.0h at the cap
Not input-path-only: `scan_lexicon` runs on the output path, so `scan_output("["
* 100_000)` took 334.7s. 0.3.2's "last quadratic site on the output path" was
false when written -- its sweep drove `[` only through `scan_active_content`.
Fix is anchor exclusion, not bounding (bounding attacker-controlled content is a
one-line bypass). The excluded char is `(`, not the obvious `[`: excluding `[`
drops `[//]: # (see [x] then ignore this)`, which no other pattern catches. The
anchors contain `(` too, so it telescopes at zero measured recall cost.
N is per row deliberately. The URL arm ran 0.9s UNFIXED at N=100_000 -- under the
2.0s bound, so that row could not have failed. Measured at N=300_000 instead,
where crafted (8.10s) and legitimate (0.926s) separate 8.8x.
Session D: move every calibration constant (entropy floors 5.4/128, 5.1/64,
4.7/40 + shape floors; MAX_SCAN_CHARS; rot13-min; cognitive-load lengths
2000/2500; disposition ranks; active-content severities) into one documented
calibration.py, so a parallel Node/TS port can mirror exactly the same numbers.
Pure refactor, zero behavior change: calibration is a leaf module (imports only
report.Severity) that entropy/lexicon/disposition/active_content now source
their thresholds from. MAX_SCAN_CHARS is re-exported from lexicon so output.py
and existing callers are unaffected. The 347 pre-existing tests pass unmodified;
new test_calibration.py freezes the values and asserts each detector actually
reads its threshold from calibration (identity-checked, not a dead copy).
Build order step 4 — the load-bearing port from the llm-security seed
(injection-patterns.mjs + string-utils.mjs), stdlib-only.
- injection_lexicon.json: 83 patterns (CRITICAL/HIGH/HYBRID/MEDIUM) as the
single source of truth (regex + id + severity + owasp + desc), compiled once
by a thin loader. Decoupled from the engine for a future TS port.
- scan_lexicon(text, source, max_scan_chars) -> Report: matches every pattern
against a deduped variant set (raw / normalized / homoglyph-folded / rot13),
plus unicode-tag presence signal and the cognitive-load trap.
- normalize_for_scan chain ported: unicode-tags -> bidi -> HTML-entities ->
unicode/hex/URL escapes -> whole-string base64 (reuses entropy.try_decode_base64)
-> collapse letter-spacing; plus fold_homoglyphs / rot13.
- Self-safety (OWASP LLM10): input-size cap (scan prefix + flag oversize) and
ReDoS-safe port — the two nested-.*? sub-agent patterns bounded to
(?:\S+\s+){0,N}?; verified true positives still fire.
- Non-Latin data (homoglyph map, BIDI block) built from explicit code points;
JSON non-ASCII kept as \uXXXX escapes.
24 tests; 55 green total.
[skip-docs]: README positioning + honest-limitations is a deliberate build-order
step-11 deliverable (steps 1-3 likewise left README frozen). README status line
("pre-implementation") is stale and flagged for the step-11 refresh.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K8GmKRCdsPjWYAKWsNgeQS
