CLI
Reports & Output
What MCPLab writes after a run and how to work with it.
Run Directory
Every mcplab run creates a timestamped directory under runs/ (or --runs-dir if set). The directory contains four files.
- results.json — structured pass/fail for every scenario, assertion, and tool call.
- trace.jsonl — full tool call trace in newline-delimited JSON. One line per LLM exchange.
- report.html — self-contained interactive HTML report. Open it in a browser.
- summary.md — short markdown summary suitable for commit comments or Slack.
results.json
The results file records every scenario run: which agent was used, which tools were called, whether each assertion passed, and the final response. It is the source of truth for all downstream reports.
trace.jsonl
The trace captures the full sequence of LLM messages and tool calls for every scenario run. Each line is a JSON object representing one exchange. Use the trace to understand exactly what the agent did and why.
Regenerating a Report
The mcplab report command regenerates report.html from an existing run directory. Use this if you update the report template or if you want to re-render a report from a CI artifact.
mcplab report --input ./runs/2026-03-01T12-00-00mcplab report --interactive