The detection half audit-core argued up to a MUST and then could not support.
Two registered sources were waiting on it.
T04, heartbeats. A heartbeat is an ordinary event — same envelope, same
append-only custody, same chain, no special table. Deliberate: a heartbeat
stored outside the chain would be the one record here that could be back-dated.
Declared per class rather than per source, because a per-source heartbeat from
a mixed-volume emitter is satisfied by its chattiest class and says nothing
about the quiet, security-relevant one, which is the only reason heartbeats
exist. Not the §17 cadence schema T05 waits on: cadence describes expected
rate, this says how often a source promises to say "nothing to report" for a
class that may legitimately be silent.
no_heartbeat_since_registration is its own finding kind rather than a skip —
it is the case most likely to be a broken integration and the one a naive
"compare against last seen" implementation silently drops. Grace widens the
window so one late run does not flap; it never removes a finding.
T06, reconciliation. Counts, never payloads. The awkward part is that every
registered sender holds may_read: false, which taken literally makes the §9.6
reconciliation obligation undischargeable by every source actually registered.
Resolved by observing that a source asking how many of its own events we hold
is not reading the archive — it learns nothing it did not itself emit. So the
surface is scoped to the caller's own sources and tenants and returns no
payloads; anything wider stays behind may_read and full tenant scope. Another
source's counts return 403 rather than an empty count, because a zero would
read as "we hold none of yours" — a false answer to a question about
completeness. No default window, since a count whose bounds the caller did not
choose is not comparable to anything the caller computed.
T07, the findings surface. /v1/stream-findings, following the dead-letter and
secret-finding conventions: may_read plus full tenant scope, since findings
span every sender and carry no tenant key to filter on.
The bound is on every response rather than in a document nobody opens beside
it. A missing heartbeat is not proof of suppression, and agreement on counts
proves neither completeness nor that any event occurred. Both controls cover
loss, outage, drain failure and accident; neither covers a source lying about
itself, and where the emitter is compromised both agree with it. Closing that
needs an observer independent of the emitter, which §16 put outside our scope.
The scope overlay may shorten a heartbeat interval or add a class, never
lengthen or remove one — same asymmetry as evidence_kind, and for the same
reason: a ConfigMap refresh must not widen the window in which a suppressed
class goes unnoticed without anyone deciding to.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nb7Q6ZmXppNDkTWytfYqfv
Assistant: claude-code
Assistant-Model: opus
Assistant-Process: 2069992@bnt-lap001
Assistant-Session: 167dd7f8-2a25-4be1-aa46-3b6f1a5f94c6
Accept now extends a single-schema chain. Verify walks it; a rewritten
payload_hash is a break. Tamper evidence is that detector plus an
external chain-head attestation, not WORM.
AUDIT-WP-0004-T04, closing the workplan.
Decision (Bernd): default to redaction, allow rejection per sender. Losing an
audit record over one field is worse than storing it masked, but a
higher-assurance channel must be able to refuse rather than mask. secret_policy
is set per sender identity in AUDIT_CORE_SENDERS and defaults to redact.
Detection now covers the whole payload at any depth, including lists, rather
than only the top level of data. Under redaction the value is masked and the
key is preserved: dropping the key would hide that the sender transmitted the
field at all, which is exactly what an operator needs in order to stop it. The
stored record carries details.redaction with policy and affected paths, so a
reader never has to infer whether what they see is what was sent.
Idempotency is unaffected - the payload hash is taken over the original request
body, so redaction is deterministic and a resubmission still reconciles as a
duplicate.
Both outcomes are counted durably by sender, source, action and field path,
exposed at GET /v1/secret-findings. Per-path aggregation is the point: the
actionable unit is "stop emitting data.auth.token on membership.added", not
"there were 47 redactions". Counters survive restart because the fix they drive
lives in another service.
Contract doc updated to match. Tests 46 -> 50. WP-0004 is finished.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
AUDIT-WP-0004 T03, T05, T06.
T03 - the receiver accepted whatever tenant and source a caller sent as long
as it held the one shared token, despite WP-0003 recording tenant isolation as
delivered. audit_core.senders binds each credential to the sources and tenants
it may assert, driven by AUDIT_CORE_SENDERS rather than literals. Identities
hold a list of tokens so rotation publishes the replacement alongside the
incumbent and needs no delivery gap. Read is a separate privilege from write,
so a sender credential cannot read the audit trail back.
T05 - lookup by event id, lookup by correlation id, and a dead-letter view.
Rejections are recorded rather than silently dropped. An event rejected for
carrying secret-shaped material has its payload withheld: storing it would
write that material into the audit store, which is what the rejection exists
to prevent. Reason and payload hash are kept so it stays traceable.
Replay is deliberately not built here. Idempotent replay is a property of the
durable store and building it against SQLite would produce a second
implementation to throw away; it lands with the Postgres backend in
AUDIT-WP-0005-T01.
T06 - serving moves to waitress with configurable threads and channel timeout,
installed in the image via the serve extra. Without it the entrypoint falls
back to a threaded wsgiref server with a socket timeout and graceful shutdown
on SIGTERM, and logs a warning so a deployment cannot quietly land on the
fallback. Metric counters deferred to WP-0005-T03 to be designed against the
real scrape path.
Tests 36 -> 46, covering cross-tenant and cross-source refusal, token
rotation, read/write privilege separation, correlation lookup, and payload
withholding on secret rejection.
Remaining in WP-0004: T04 redaction policy, which needs a decision on whether
a secret-shaped field is a rejection or a redaction.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
AUDIT-WP-0004 T01, T02, T07.
T01 - ingestion wrote to SQLite directly and never called the AuditBackend
contract, so a 202 meant a row existed rather than that a backend with a
declared retention policy had accepted the event. Adds IdempotentAuditBackend
to the contract: duplicate detection lives inside the backend so custody and
idempotency state share a transaction and cannot diverge. SQLiteAuditBackend
implements it with WAL, synchronous=FULL and a busy timeout. Ingestion now
refuses any backend declaring durable=False, so the development file backend
cannot silently become the production sink.
The atomicity claim was tested rather than asserted, and the first attempt
failed: with a single shared connection, 16 racing submissions of one event
told two callers they were first. Storage was correct but the response was
not. Fixed with per-thread connections and BEGIN IMMEDIATE around the
insert/read pair, and locked in by a test.
T02 - storage errors previously escaped the handler with start_response never
called, and the auth check sat outside the try block so a non-ASCII
Authorization header crashed the request. Adds a catch-all, maps conflict to
409, backend unavailability to 503 and unexpected faults to 500, and
documents the full response contract with the retry semantics each status
implies, since senders key their behaviour off it.
T07 - ingestion tests 2 -> 23, suite 15 -> 36. accepted_at is now UTC rather
than local time, and naive timestamps are rejected instead of silently
assumed.
Remaining in WP-0004: T03 tenant/source binding, T04 redaction policy,
T05 operator read surface, T06 production serving layer.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
