Muse Code vs Pi

At a glance

What each one is

This page compares Pi, the coding agent from Earendil at pi.dev. Pi describes itself as a minimal agent harness. You customize it with extensions, skills, prompt templates and themes. It runs in a terminal, in scripts, over RPC, or inside your own app through its SDK.

Muse Code is Meta's coding CLI. Helicon is a free, MIT licensed desktop and web client for it. It is community built and not affiliated with Meta. Helicon uses your own muse login and your own Muse Code subscription, and it is not a separate agent.

Where they actually differ

Window or terminal

Pi's main interface is a terminal UI, with a session tree you move around by command. Helicon is a window for Muse Code sessions. It lists sessions across projects, shows diffs inline, and lets you resume a past session.

Models

Pi lets you switch between providers and models mid-session. Its site names Anthropic, OpenAI, Google, xAI, Ollama and others. Helicon works with Muse Code through the muse CLI and does not set up a model of its own.

How you customize it

Pi's pitch is that you change the agent itself with TypeScript extensions, skills and shareable packages. Helicon is a client. You can read and change its source, which is MIT licensed, but it does not change how Muse Code behaves.

Cost

Helicon costs nothing. You pay Meta for Muse Code, through your own plan or pay-as-you-go billing on Meta's Model API. Pi is free and MIT licensed, and no paid tier is listed on pi.dev or its repository. What you pay depends on the provider you connect.

Choose the Pi coding agent if

• You want one agent that works across many model providers, and you want to switch models mid-session.
• You want to shape the agent with extensions, skills and prompt templates instead of using it as shipped.
• You want to embed an agent in your own app through Pi's RPC mode or SDK.
• You prefer a minimal terminal tool and are happy to add features like plan mode yourself.

Choose Helicon if

• You already pay for Muse Code and want its sessions in a window.
• You want approvals and inline diffs shown in each thread.
• You want a free, MIT licensed client with no account.
• You want one UI that also runs in a browser against a remote daemon.

Can you use both?

You can open both on the same project folder. Use Pi in a terminal for one task and Helicon for Muse Code threads, with their history and approvals. They are separate agents with separate sessions, so neither sees the other's history.

Helicon is one Muse Code GUI of several, and that page lists the rest. Helicon is free and MIT licensed, and you can try Helicon in your browser on sample data before you install anything.