A new open-source TypeScript library addresses EU AI Act Article 12 compliance requirements for high-risk AI systems. The legislation, which entered force and requires automatic event recording with six-month retention starting August 2025, creates a need for tamper-proof audit trails that many existing observability tools cannot provide.

Developers working with the Vercel AI SDK now have a solution that captures inference calls as append-only logs stored in structured JSONL format. The library automatically logs every AI interaction, chains entries using SHA-256 hashes for tamper detection, and enforces a 180-day retention floor. A CLI tool enables decision reconstruction and integrity verification, while a coverage command identifies potential logging gaps.

The library targets Node.js applications using Vercel's AI SDK and supports both S3 storage and local filesystems. Its deliberately simple architecture uses linear hash chaining and works with agentic frameworks like Mastra. The creator welcomes community contributions to expand integrations.