Christian Klotz
85c2ee3e76
## Summary The docs refresh (#9898) cut `docs/extensions.md` from about 3,100 lines to 130, dropping API reference and tool guidance. #11039 restored part of it. This PR restores the full guide and corrects it against current source. - **Structure:** the original sections, with the ASCII lifecycle diagram replaced by three Mermaid diagrams (run, turn, session) and ordered hook lists, plus a handler composition table. - **Merged:** content added after the cut: tool exposure, calling other tools, structured output, MCP servers, `registerToolRenderer`, virtual models, `provider_stream_event`, `before_agent_start` `messageType`. - **Corrected:** removed or renamed APIs (`modelRegistry.stream()`, prompt sections are `<tools>`/`<rules>`, `builtin:read` paths, `highlightCode`), wrong behavior claims (errors only by throwing, `model_select` on restore, `sendUserMessage` always triggering a turn, override warning, `truncateLine` bytes), examples that did not type-check, links to removed `tui.md` patterns and `rpc.md` anchors, and wrong API lists in the examples table. - **Kept:** anchors that other docs and changelogs link to, as `<a id>` tags. - **Fixed example:** `reload-runtime.ts` tool queued `/reload-runtime` with `deliverAs: "followUp"`. Queued text reaches the model as a plain user message, so the command never ran and Pi never reloaded. The tool now sets a flag and returns `terminate: true`; an `agent_settled` handler sends `/reload-runtime` with `expandPromptTemplates: true`, which runs after the settled handlers finish, while the agent is idle. In the long run it may be better to revisit how API reference is, provided to the agent, especially since more capable models do explore the source without it. ## Validation - `npm run check` - Edited TypeScript examples type-check against current types - All relative links and anchors in `extensions.md` resolve, including inbound anchors from other docs - `reload-runtime.ts`: faux-provider harness test (temporary, not committed) shows one reload after the run settles and no extra model request; the old version never reloads. Also verified in interactive mode with a real model. - Reviewed by GPT-6 Astra and GPT-5.6 Sol against source; all findings applied
New issues and PRs from new contributors are closed automatically. Maintainers review closed submissions daily. See CONTRIBUTING.md.
Pi
Pi is a minimal, extensible agent harness that you can make your own.
Adapt Pi to your workflows, not the other way around. Customize Pi with extensions, skills, prompt templates, and themes. Bundle them as Pi packages and share via npm or git.
Pi ships with powerful defaults but skips features like sub-agents and plan mode. Ask Pi to build what you want, or install a package that does it your way.
Use Pi interactively, automate it in print or JSON mode, control it over RPC, or build apps with the Pi TypeScript SDK. See OpenClaw for a real-world integration.
Getting started
Install the command-line interface:
curl -fsSL https://pi.dev/install.sh | sh
On Windows:
powershell -c "irm https://pi.dev/install.ps1 | iex"
The installer pins all dependencies and updates Pi with pi update. Alternatively, install directly with npm, which does not pin transitive dependencies:
npm install -g --ignore-scripts @earendil-works/pi-coding-agent
Pi requires Node.js 22.19 or newer. The macOS, Linux, and Windows installers can install it if needed. Pi does not require dependency lifecycle scripts for a normal npm installation.
On macOS and Linux, Nix users can install the latest release with nix profile add github:earendil-works/pi/stable. See the quickstart for updating and pinning releases.
Start Pi in the directory where you want it to work:
cd /path/to/project
pi
For a built-in AI provider, run /login inside Pi to connect a subscription or API key. Then give Pi a task.
See the documentation for full setup and usage instructions.
Share your OSS coding agent sessions
If you use Pi for open source work, please share your coding agent sessions.
Public OSS session data helps improve models, prompts, tools, and evaluations using real development workflows.
For the full explanation, see this post on X.
To publish sessions, use badlogic/pi-share-hf using a Hugging Face account and the Hugging Face CLI.
- Demo video on how to publish Pi sessions
- Published Pi development sessions:
badlogicgames/pi-monoon Hugging Face.
Development
Clone the repository, install its dependencies, and run Pi from source:
git clone https://github.com/earendil-works/pi
cd pi
npm install --ignore-scripts
./pi-test.sh
pi-test.sh can be called from any directory and preserves the caller's working directory.
Before submitting changes, run:
npm run check
./test.sh
Read CONTRIBUTING.md before opening an issue or pull request. It defines the contribution gate, issue quality bar, and required checks. Read AGENTS.md for repository-specific implementation, testing, dependency, and release rules.
License
MIT