Helicon vs T3 Code for Muse Code

At a glance

What each one is

T3 Code is an open source GUI for coding agents from the t3.gg team. It runs many agents in one app, can hand context across providers in the middle of a conversation, and has desktop, web and mobile clients. In October 2026 it added a Muse Code provider, labelled beta and switched off by default.

Helicon is an unofficial, MIT licensed client built only for Muse Code. It ships as a desktop app, a web app and an editor extension. Both tools start muse serve and talk to it through Meta's official @muse-code/sdk, so the difference is not the protocol. It is how much of Muse Code each one exposes. The rows on this page describe T3 Code's Muse provider as of 8 October 2026; a beta moves fast, so check its docs too.

Where they actually differ

Approval modes

Muse Code has its own approval modes: onRequest, promptUnmatched and denyUnmatched. Helicon maps them one to one and lets you change the mode inside a session. T3 Code's Muse provider uses its own two levels, Supervised and Full access, the same switch it uses for every agent.

Sessions you started in the terminal

Helicon lists every Muse Code session for a workspace, including sessions started with muse in a terminal, and resumes them with their full history. T3 Code resumes the threads it created itself.

Fork, workflows and background work

Helicon uses Muse Code's native fork, and has controls for workflows and background tasks: cancel a workflow, skip or retry an agent, send a task to the background, stop one or all. T3 Code copies context into a new session to branch, and shows workflow and subagent output without those controls.

Plan usage and cost

Helicon reads Muse Code's usage meter, so you see the 5 hour and weekly windows, plus what each thread would cost at API rates. T3 Code shows token and context counts.

Where it runs

T3 Code has a mobile client and remote access to another machine, which Helicon does not have yet. Helicon has an editor extension for VS Code, Cursor, Windsurf and VSCodium, runs Muse Code natively on Windows or inside WSL2, and shows install and login steps in the app when the muse CLI is missing.

Choose T3 Code if

• You use several agents and want them all in one app.
• You want to hand a conversation from one agent to another.
• You want a mobile client or remote access today.
• You already use T3 Code and only try Muse Code now and then.

Choose Helicon if

• Muse Code is your main agent and you want all of its features, not a common subset.
• You start sessions in the terminal and want to pick them up in a GUI.
• You want the plan meter and cost per thread.
• You want Muse Code inside VS Code, Cursor, Windsurf or VSCodium.

Can you use both?

Yes. Both drive the same muse CLI with your own muse login, so neither one stores your credentials and installing both costs nothing. A common split is T3 Code for mixed agent work and Helicon for long Muse Code sessions.