@cendor/acttrace

A tamper-evident, auto-populated audit log for AI decisions. The TypeScript port of cendor.acttrace (regex/pattern detectors only — no Presidio).

Construct an AuditLog and it subscribes to @cendor/core's event bus: every instrumented model/tool call becomes a hash-chained audit entry with zero per-call wiring. You add only the explicit human-facing events (decision, humanOversight). Integrity comes from a hash chain, not a server: entry.hash = sha256(prev_hash + canonical(entry)), so editing any past entry breaks every entry after it — and verify() re-walks the chain offline.

Byte-conformant with Python: a chain written by JS verifies in Python and vice-versa. The hashed canonical bytes and HMAC inputs are identical across languages (snake_case wire keys, int/float preserved, prev_hash text-prepended, GENESIS = 64 zeros).

Evidence, not a guarantee. acttrace produces tamper-evident evidence to support a compliance case — it is not a compliance guarantee and does not make a system "EU AI Act compliant" (or compliant with any framework). The control-ID annotations from log.export(path, framework) map entries to a framework's articles; the assessment itself is always yours.

Killer example

import { instrument } from '@cendor/core';
import { AuditLog, verify } from '@cendor/acttrace';

const log = new AuditLog('loan_triage', { riskTier: 'high', path: 'audit.jsonl' });
const client = instrument(openai); // one seam; acttrace rides the bus

await log.decision(
  async (d) => {
    // this call is auto-captured as an `llm_call` entry, tagged to the decision
    await client.chat.completions.create({ model: 'gpt-4o', messages });
    d.record({ model: 'gpt-4o', prompt_id: 'triage@v3' });
    d.humanOversight('ops@bank', 'approved', 'manual check');
  },
  { input: { amount: 5000 } }, // PII in inputs is auto-redacted + flagged before hashing
);

log.export('evidence.jsonl', 'eu_ai_act'); // annotate with control IDs + a signed-completeness header
log.detach();

const [ok, detail] = verify('audit.jsonl'); // re-walk offline; catches any edit / reorder / truncation

Surface

Symbol	What it does
`new AuditLog(system, opts?)`	Hash-chained, auto-populating log. `opts`: `riskTier`, `path`, `signingKey`, `redact`, `redactor`, `flagOnRedact`, `policy`, `maxEntries`. Auto-subscribes to the bus.
`log.decision(cb, { input?, actor? })`	Async-scoped decision span (`AsyncLocalStorage`); auto-captured calls inside `cb` are tagged.
`d.record(fields)` / `d.humanOversight(reviewer, action, note?)` / `d.flag(reason, opts?)`	Explicit decision events.
`log.flag(reason, { action?, severity?, data?, extra? })`	Record a `policy_flag` (action/severity lowercased).
`log.export(path, framework?)`	JSONL evidence pack + `_meta` header (control mapping, summary, signed completeness).
`log.head` / `log.evictedFromMemory` / `log.detach()`	Chain head, ring-eviction count, unsubscribe + close.
`verify(path, { key?, expectedHead?, expectEntries? })`	`[ok, detail]`. Never throws. Detects tamper / bad-sig / reorder / truncation.
`frameworks()`	`['eu_ai_act', 'gdpr', 'iso_42001', 'nist_rmf']`.
`scan(obj, policy?)` / `redact(obj, policy?)`	Pure detection (counts only) / scrub. `Policy.default/gdpr/pci/strict`.
`guard(policy?, audit?, onBlock?)`	Interceptor for `addInterceptor`: block (throw) / redact-before-send (`Reroute`) / flag. `PolicyViolation.findings`.
`DETECTORS`, `registerDetector`, `detectors`, `Detector`	The 20-detector registry (validators: Luhn / IBAN mod-97 / Verhoeff / ABA / SSN / phone / BIC).
`enableLocalePack('uk'\|'in')`, `enableEntropyDetector()`, `LOCALE_PACKS`	Opt-in packs (off by default).
`nerAvailable()` / `nerRedactor()`	Regex-only port: returns `false` / throws (no Presidio in JS).
`chainHash`, `metaSignature`, `GENESIS`, `AuditEntry`, `BoundedMemoryWithoutPathWarning`	Low-level conformance primitives + types.

Wire the guard in one line:

import { addInterceptor } from '@cendor/core';
import { AuditLog, Policy, guard } from '@cendor/acttrace';

const log = new AuditLog('support_bot', { riskTier: 'high' });
addInterceptor(guard(Policy.gdpr(), log)); // enforce + record; recorder and enforcer stay separate

Parity note

Python snake_case kwargs become a trailing options object; string-literal values are unchanged (action: 'blocked', evict semantics, framework ids). Python context managers (with log.decision(...) as d:) become the async-callback form await log.decision(async (d) => …, opts), scoped with node:async_hooks AsyncLocalStorage. Class/type/error names are byte-identical (AuditLog, AuditEntry, Policy, Finding, Detector, PolicyViolation, verify). Hashing is synchronous via node:crypto; storage (fs/memory) and crypto are lazily required so importing the package never forces Node built-ins into a browser bundle. NER is intentionally absent — the JS port ships the regex/pattern detectors only.