RFC: governed domain audit append

[joshuajbouw]

Summary

Specify a governed astrid:audit@1.0.0 host interface for bounded capsule-owned domain assertions in Astrid's durable, runtime-signed audit chain.

The capsule supplies only a typed assertion and evidence digests. Astrid stamps effective authority, exact component provenance, ordering, chain linkage, key identity, and signature, and returns a durable inclusion receipt.

Why

The runtime can audit operations it observes, but it cannot infer domain facts such as which Codewall policy and rules produced a decision. The event bus is not a durability boundary, while a generic guest-controlled append would permit provenance spoofing, unbounded secret dumping, and replay amplification.

Design highlights

• install-approved schema allowlists rather than arbitrary log authority;
• fixed capsule-assertion provenance, distinct from kernel observations;
• bounded scalar attributes and digest references rather than opaque payloads;
• transactional entry, head, sequence, and idempotency updates;
• retry-safe inclusion receipts and conflict detection;
• quota isolation with capacity reserved for kernel audit events;
• canonical encoding, verification, recovery, and backward-compatibility rules.

Tracks astrid-runtime/astrid#1472.

Validation

• RFC checked against the current Astrid audit, invocation-context, capability, manifest, storage, and WIT boundaries.
• Threat model covers source impersonation, false assertions, replay, concurrency, storage tampering, resource exhaustion, and sensitive-data leakage.

AI / Tool Assistance

Assisted-by: Codex:GPT-5.6

Codex assisted with codebase reconnaissance, adversarial design review, and drafting. I reviewed the proposed authority boundary, compatibility rules, threat model, and implementation acceptance criteria.