Building a Tamper-Evident Audit Log for Autonomous AI Agents: A Postmortem

Short summary

The author audits their autonomous AI agent's claim of an immutable history log and finds it broken by concurrent writers, missing locks, and corrupted records. The fixes include a single-writer invariant enforced by the OS, external cryptographic signatures anchoring the chain, scheduled verification of signed heads, and an explicit epoch-boundary mechanism for legitimate history repair. The post is a candid engineering postmortem on what 'can't rewrite history' actually requires.

• •Hash chain audit log was broken by concurrent writers and race conditions despite appearing append-only
• •Fixes: single-writer lock, external signature anchoring, scheduled verification, and explicit epoch re-genesis for repair
• •Internal chain consistency proves nothing — external cryptographic anchors are needed to prevent full-chain forgery

Generated with AI, which can make mistakes.