The Librarian — Pi extension

A Pi package that gives the Pi coding agent durable memory and cross-harness handoffs, backed by a remote Librarian MCP server.

Pi's core has no MCP support, so this extension does the wiring itself: it registers the Librarian's 7 agent verbs as native Pi tools (each one a thin, fail-soft proxy over the server's stateless /mcp endpoint) and injects the Librarian primer into the system prompt. One install, zero config files.

What you get

• 7 tools, identical to every other harness — recall, remember, flag_memory, store_handoff, list_handoffs, claim_handoff, search_references. Descriptions and schemas mirror the server's (a drift-guard test pins them), so the model is taught the same protocol in Pi as in Claude Code, Codex, OpenCode, and Hermes.
• Primer injection — the operator-editable vault/primer.md (≤2KB) is fetched once per process from GET <server>/primer.md and appended to the system prompt via before_agent_start.
• Four slash commands (optional sugar): /handoff, /takeover, /learn, /toggle-private — thin prompt templates that drive the corresponding tool flows. See docs/slash-commands.md.
• Fail-soft everywhere — if the Librarian is down, tools return a short error string (never a thrown harness error), the primer is skipped, and the user's turn is never blocked.

Install

From npm (once published — see "Publishing" below):

pi install npm:@the-librarian/pi-extension

From source (works today):

git clone https://github.com/JimJafar/the-librarian
pi install /path/to/the-librarian/integrations/pi

(pi install git:… of the monorepo root won't work — the package lives in the integrations/pi subdirectory, so install from a local clone path.)

Configure

Set two environment variables in the shell that launches pi:

Variable	Meaning
LIBRARIAN_MCP_URL	The server's MCP endpoint, e.g. https://your-librarian/mcp
LIBRARIAN_AGENT_TOKEN	A per-agent bearer token issued by your Librarian
LIBRARIAN_TIMEOUT_MS	(optional) per-call timeout, default 15000

Without both required variables the extension stays dormant: no tools, no network calls — only the four slash commands register, and they explain what's missing.

Security posture (inherited from the security-reviewed clients in this family): the bearer token travels only in the Authorization header, redirects are refused so a 3xx can't carry the token cross-origin, the endpoint scheme is allowlisted to http(s), and response bodies are size-capped.

Develop

This package is part of the the-librarian pnpm workspace:

pnpm install
pnpm --filter @the-librarian/pi-extension test        # vitest
pnpm --filter @the-librarian/pi-extension typecheck   # tsc --noEmit

The schema-parity suite imports the compiled @librarian/mcp-server, which is built automatically on pnpm install (its prepare script).

Publishing

The package is publishable ("private": false) and carries the pi-package keyword, so npm publish from integrations/pi/ both releases it and lists it in Pi's gallery at pi.dev/packages. Publishing is a repo-owner action — it is deliberately not part of any automated flow here. Until it's published, use the "from source" install above.