A self-hosted chat interface for the Pi coding agent.

One Go binary. Chat in the browser while Pi reads files, runs commands and draws charts in a workspace folder.

For each chat Harf runs pi --mode rpc and streams Pi's answer to the browser. Pi works in a workspace folder, so a chat can do real work, not just talk.

Features

• Any model Pi can use: pick one per chat; streaming replies with Markdown, math and highlighted code.
• Steps: every file Pi reads or writes and every command it runs shows in the reply.
• Chats: stop, edit and resend, regenerate, search, pin, rename, export as Markdown.
• Agents: saved instructions, model, thinking level and allowed tools; or ask in a chat and Pi builds one.
• MCP servers: add a command or a URL in Settings and Pi uses its tools.
• Plugins: attachments up to 100 MB, workspace images, charts, sandboxed HTML pages, image generation through OpenRouter.
• Command palette, light and dark themes, token and cost stats under each reply, phone layout.
• Docker image for linux/amd64 and linux/arm64.

Quick start

Install Pi 1.4.0 and sign in (run pi, then /login) or set a provider key, then download Harf and run it:

# macOS on Apple silicon; for others use darwin_amd64, linux_amd64 or linux_arm64
curl -fsSL https://github.com/aktech/harf/releases/latest/download/harf_darwin_arm64.tar.gz | tar -xz
./harf_darwin_arm64/harf    # http://127.0.0.1:8080

Each release lists the archives' SHA-256 hashes in SHA256SUMS.

Or with Docker, which has Pi inside, with your provider keys in keys.env as NAME=value lines (which names):

docker run -p 8080:8080 --env-file keys.env -v harf:/home/user ghcr.io/aktech/harf:main

Or from source: make build && ./bin/harf.

Warning

Harf has no sign-in of its own, and Pi runs commands for whoever can reach it. Keep it on localhost, or behind an authenticating reverse proxy. See security.

Develop

make test    # go vet, Go tests and the web tests (node --test)
make run     # build and run on http://127.0.0.1:8080

The web UI is plain JavaScript modules in web/, with no build step.

Documentation

• Configuration: environment variables, MCP servers, plugins
• Deploy with Docker: image tags, volumes, building the image
• Security: no sign-in, command execution, MCP servers, /api/me headers

License

Apache License 2.0. The libraries, fonts, logos and icons in web/vendor/, web/fonts/, web/logos/ and web/icons/ keep their own licences, which sit next to them.