Local Ci

What local-ci does

Runs the official GitHub Actions runner binary locally (in Docker), emulating GitHub's cloud API. Cache is bind-mounted (instant). When a step fails, the container pauses — you can fix and retry the failed step without restarting.

When to use local-ci (not act)

• You want bit-for-bit compatibility with remote GitHub Actions
• You need pause-on-failure for AI agent debugging loops
• Cache round-trip speed matters

Key commands

• Run workflow: npx run-local-ci run --workflow <path>
• Run all relevant workflows (those whose on triggers match the current branch/event, just like GitHub): npx run-local-ci run --all
• Retry after fix: npx run-local-ci retry --name <runner>
• Abort: npx run-local-ci abort --name <runner>

Agent output mode

Pass --json (or set LOCAL_CI_JSON=1) to emit an NDJSON event stream on stdout — one JSON object per line, with run.start/paused/finish, job.start/finish, step.start/finish, and diagnostic events. run.start carries schemaVersion: 1. Pair with --pause-on-failure: when stdout isn't a TTY the launcher detaches and the foreground process exits 77 the instant a run.paused event fires, so callers can react cleanly without parsing plaintext.

Common mistakes

• Don't push to remote CI to test changes — use npx run-local-ci run locally first
• Don't use --from-start when only the last step failed — use retry with no flags to re-run only the failed step
• The AI_AGENT=1 env variable disables animated output for cleaner agent logs
• Use --no-matrix to collapse matrix jobs into a single run — your local machine is likely faster than GitHub's runners, so parallelizing across matrix combinations is unnecessary