May 2026 (facebook/buck2): Focused on improving test run traceability for AI-assisted testing and delivering measurable business value. Implemented automatic AI agent tagging for buck2 test runs, enabling precise attribution of test results to specific AI agents by detecting CODING_AGENT_METADATA on the client side and populating agent_context. This information propagates through the TPX/Result Recorder pipeline (ai-agent, ai_agent_id, ai_inv_id), with a built-in 80-character tag length cap to prevent TPX failures. Added 7 unit tests and end-to-end verification to ensure CODING_AGENT_METADATA flows into agent_context and is reflected in invocation records. Maintained zero IO cost and no external dependencies, preserving performance while delivering robust telemetry and analytics for AI-driven testing.