pi-librarian

A GitHub research subagent for the pi coding agent inspired by Amp: deep-dive questions about specific repos ("how does drizzle-orm implement prepared statements?") and discovery across the ecosystem ("compare the most popular TypeScript SQL ORMs").

How it works

The librarian tool spawns a research subagent with purpose-built tools:

• checkout_repo — clone into a local cache, where it can be read locally, and git log -S/blame/diff covers history.
• search_repos — GitHub repository discovery (stars, topics, other metadata).
• search_code — cross-repo public code search via Grep (regex, global discovery, repo/language/path filters).
• search_github_code — GitHub REST code search over public code and private repositories your configured GitHub auth can access.
• read_github_file — single-file API reads for quick peeks without cloning.

Usage

• Ask pi a question involving other repos; it asks the librarian.
• Ask follow-up questions to earlier librarian runs.
• /librarian attaches the research tools directly to your session for direct tool usage.
• Recommended: install pi-web-access (or your web search of choice, tho this one is zero-config to get started) and add web_search, fetch_content, get_search_content to librarian.tools to expand past GitHub-only research.

GitHub auth for private repos

Public GitHub reads work without configuration. To let the librarian search and read private GitHub repositories, provide a token in one of these ways:

1. Set GITHUB_TOKEN or GH_TOKEN in the environment before starting pi.
2. Or authenticate the GitHub CLI so gh auth token returns a token:

The token is loaded once per pi session and used for github access in search_repos, search_github_code, checkout_repo, and read_github_file. For private repositories, use a token with read access to the target repos.

Configuration

In pi's global settings.json:

{
  "librarian": {
    "model": "openai-codex/gpt-5.5",
    "thinkingLevel": "off",
    "tools": ["web_search", "fetch_content", "get_search_content"],
    "extensions": ["~/.pi/agent/extensions/parallel-web-tools"],
    "cacheDir": "/tmp/pi-librarian",
    "debug": { "persistRuns": false },
  },
}

Setting	Recommended	Default
model	openai-codex/gpt-5.5	current session model
thinkingLevel	off	current session thinking level
tools	names of extra tools to provide the librarian	[]
extensions	extra paths to load extensions for the librarian	[]
cacheDir	/tmp/pi-librarian	/tmp/pi-librarian
debug.persistRuns	persist nested session file paths for debugging	false

librarian.extensions dynamically loads extra extensions just for the librarian. Add any tools from that extension to librarian.tools for the librarian to actually be able to use them. Librarian excludes write and edit.

Development

npm run check                       # biome + tsc + vitest
pi -e ./extensions/librarian.ts     # run pi with this extension loaded