What changed
Rashomon alpha v1.1.0 is an Apache-2.0 open-source tool for macOS and Linux that integrates with Claude Code hooks to record execution events separately from the agent's own closing summary. It tracks tool calls, subagents and failures and flags a discrepancy when the summary fails to acknowledge recorded errors. The project supplies a reproducible acceptance-test fixture showing a failed test run alongside a success claim. The local recorder does not store prompt text or file contents and says it has no telemetry; its own README explicitly excludes Windows support, network observation and tamper-proof protection.
Why it matters
Coding agents can produce plausible summaries even when a command failed or a subagent encountered problems. The normal final diff or assistant message may not show the full execution path. A second, inspectable event record gives builders a way to verify what actually ran and whether a test failed before accepting the agent's conclusion. The practical lesson is to separate evidence of execution from an agent's narrative, while understanding that a local recorder does not enforce security boundaries or prove correctness.
Independent event capture instead of another agent summary
Rashomon uses Claude Code hooks to capture tool execution and subagent activity into a local record, then compares important failures with the wording of the agent's final summary.
The project's own acceptance test demonstrates the discrepancy
A repository acceptance fixture deliberately shows a failed test call and an agent summary saying tests pass. The report surfaces the failed call and missing acknowledgement; this demonstrates intended behaviour, not a measured failure rate in real deployments.
Data retention and limits are explicit
The README says it discards prompt and file contents and stores compact command metadata locally. It is alpha software, supports Claude Code on macOS/Linux, does not observe network traffic, and cannot prevent a determined agent from altering its records.
An audit trail is not containment
Rashomon does not stop a command, restrict file or network access or certify a change as correct. Teams should pair independent logs with actual tests, code review and a sandbox where appropriate.