Domain: audit

Curated entry point for the audit bounded context.

Owner

Founder + Risk Officer + agents (Phase 1). The audit log is regulated content; the Risk Officer signs off on retention and immutability posture.

Mission

Owns the firm-wide audit log: a per-row hash-chained queryable log in Postgres for the operational audit, with near-real-time async replication to AWS S3 with Object Lock COMPLIANCE retention for tamper-evident regulatory archival. Boundary: audit records events; it does not generate them - every other domain produces audit-relevant events that audit consumes, hash-chains, and persists.

Code paths

• Application code: apps/api/src/modules/audit/
• Domain logic (pure): packages/domain/audit/ (hash-chain implementation)
• Contracts: packages/contracts/events/audit.ts
• Database schemas owned: audit (AuditEvent, AuditChain, ArchivalCheckpoint)
• S3 archival: astrix-prod-audit-log bucket per Q-E10

PRD chapters that touch this domain

• 13-compliance-legal.md - regulatory retention obligations
• 16-open-questions.md - Q-E7 (audit log storage: Postgres + hash chain + S3 Object Lock; replication SLO), Q-E10 (per-bucket policy)
• 12-non-functional.md - audit-log RPO/RTO targets
• 09-admin-backoffice.md - admin search of audit events

TDD chapters

(Empty - will populate.)

ADRs that affected this domain

• ADR-0001 (transversally applies)

Service interfaces this domain exposes

export interface AuditService {
  // recordEvent(event: AuditEvent): Promise<AuditEntry>
  // searchEvents(query: AuditQuery): Promise<AuditEntry[]>
  // verifyChain(fromTimestamp, toTimestamp): Promise<ChainVerificationResult>
  // exportRange(fromTimestamp, toTimestamp): Promise<ExportJobId>
  // (full surface defined during audit TDD)
}

Events this domain produces / consumes

Direction	Topic	Schema
consumes	* (all <domain>.*.audit topics)	The audit module subscribes to a curated set of audit-relevant events from every domain
produces	audit.entry.recorded	Confirmation that an event was hash-chained and written
produces	audit.archive.checkpoint	Periodic checkpoint of "everything up to offset N is archived to S3"
produces	audit.chain.broken	(Critical alert) Hash-chain integrity check failed

External integrations

• AWS S3 with Object Lock COMPLIANCE (per Q-E10) - immutable archival
• MinIO - non-prod equivalent

Runbooks for this domain

(Empty - will populate. Expected high-priority: hash-chain broken, replication-lag-exceeds-60s, S3 Object Lock retention failure.)

On-call

To be filled in Section 17.6. Hash-chain integrity is Sev 0; replication lag is Sev 1.

Cross-domain dependencies

• This domain consumes events from: every other domain (it is a leaf consumer).
• This domain emits events consumed by: admin (operational audit search), notifications (Sev 0 hash-chain-broken alert).
• No synchronous outbound dependencies.