opencode-librarian

OpenCode plugin that adds a Librarian subagent for remote code research. It is designed for deep source investigation across repositories, with long-form answers that cite evidence and point to permalinks when code details matter.

Inspiration

• Heavily inspired by the Librarian agent in oh-my-opencode.
• Aligned with the Librarian concept described by Ampcode.

Usage

• Install and build the plugin, then enable it in your OpenCode config.
• Ask explicitly for the Librarian when you need remote code research or upstream library internals. This plugin only registers the agent; it does not add auto-routing or keyword triggers, so OpenCode will not invoke it unless you select it or ask for it explicitly.

Default model configuration:

• This plugin ships with a default model defined in src/constants.ts.
• Recommended default: gemini-3-flash.
• To override it, set the agent model in your OpenCode config, for example:

{
  "agent": {
    "librarian": {
      "model": "gemini-3-flash"
    }
  }
}

Example prompts:

• "Use the Librarian to look up how React's useEffect cleanup is implemented."
• "Ask the Librarian to explain why this Zod validation error occurs and show the logic causing it."
• "Use the Librarian to trace how our docs get deployed across the docs and infra repos."

Install

bun install
bun run build

Add the plugin to ~/.config/opencode/opencode.json:

{
  "plugin": [
    "file:///Users/andrew/dev/opencode-librarian"
  ]
}

Development

bun install
bun run build