pi-mono-auto-fix

End-of-turn formatter/linter dispatcher for pi. Collects every file written during a turn and applies language-appropriate fixers (eslint, black, prettier, …) in one batch once the agent stops talking.

What it does

• Subscribes to tool_result for the built-in edit and write tools, plus the context-guard:file-modified event that multi-edit and other writers emit.
• Buffers absolute paths of touched files in a per-turn Set.
• On agent_end, groups paths by matching fixer, runs each fixer once per group (parallel up to concurrency).
• After each run, re-emits context-guard:file-modified for any file whose mtime actually changed, so downstream read caches evict.
• Emits a single notification at the end (auto-fix: N/M files updated).

Fixers are invoked silently — stdout/stderr are swallowed. Failures are reported in the summary notification but never surfaced into the LLM context.

Built-in fixer rules

Extensions	Command
.ts .tsx .js .jsx .mjs .cjs	npx --no-install eslint --fix --no-error-on-unmatched-pattern {files}
.py	black -q {files}
.json .md .yml .yaml .css .scss .html	npx --no-install prettier --write --log-level=warn {files}

{files} is replaced with shell-quoted, space-separated absolute paths. If the token is missing, files are appended to the end of the command.

Commands run with shell: true, cwd = ctx.cwd, and a per-invocation timeout (default 60s).

Configuration

Resolution order (first hit wins):

1. PI_AUTO_FIX=0 → extension is fully disabled (no listeners registered)
2. ~/.pi/agent/auto-fix.json
3. built-in defaults

Example ~/.pi/agent/auto-fix.json:

{
  "enabled": true,
  "timeoutMs": 90000,
  "concurrency": 2,
  "ignore": ["node_modules/", "dist/", ".git/", "vendor/"],
  "fixers": [
    {
      "label": "biome",
      "extensions": [".ts", ".tsx", ".js", ".jsx"],
      "command": "npx --no-install biome check --write --no-errors-on-unmatched {files}"
    },
    {
      "label": "ruff",
      "extensions": [".py"],
      "command": "ruff check --fix {files} && ruff format {files}"
    }
  ]
}

All fields are optional; anything omitted falls back to the built-in default.

Install

pi install npm:pi-mono-auto-fix

Or load directly for testing:

pi -e /path/to/pi-extensions/extensions/auto-fix/index.ts

Notes

• Paths outside ctx.cwd are skipped for safety.
• Paths matching any substring in ignore are skipped.
• Files deleted during the turn are skipped (existence is re-checked at flush time).
• The mtime diff catches fixers that are no-ops on already-clean files, so the summary reflects real changes rather than just invocations.