Muse Code for VS Code (Unofficial)
A native VS Code chat UI for Muse Code, Meta's agentic terminal coding agent.
Unofficial community project. This extension is not made, endorsed, or supported by Meta. "Muse" and "Muse Code" are Meta's names for their product; they are used here only to describe what the extension connects to.
Inspired by the Claude Code VS Code extension. The layout, commands, keybindings, settings and workflow of this extension deliberately mirror Anthropic's Claude Code for VS Code so that anyone who knows that extension feels at home. This project is not affiliated with Anthropic or Meta.
- Works alongside you: Muse explores your codebase, reads and writes code, and runs terminal commands with your approval.
- Integrated with the editor: Muse knows about your current file and text selection, and you can review its file changes as a diff right in the editor.
- Durable sessions: resume any past conversation for the workspace, including ones started from the
muse terminal TUI.
- Agentic features supported: approvals with policy amendments, user-input questions, subagents, todo lists, context compaction, model and reasoning-effort selection, and user shell commands.
Requirements
- VS Code 1.98.0 or higher.
- The
muse CLI, version 1.0.3 or later. Run muse login once before using the extension. The extension looks for muse on PATH, in common install locations (~/.local/bin, /opt/homebrew/bin, ...), and via your login shell, so it works even when VS Code is launched from the Dock. Set museCode.executablePath only if it still cannot be found.
Getting started
- Open a folder.
- Click the Muse icon in the editor title bar, or press
Cmd+Escape (Ctrl+Escape on Windows/Linux).
- Type a message and press Enter.
Use @ to mention files, / for commands, and ! to run a shell command yourself.
Commands
| Command |
Default keybinding |
| Muse Code: Open |
Cmd/Ctrl+Escape (focus) |
| Muse Code: Open in New Tab |
Cmd/Ctrl+Shift+Escape |
| Muse Code: Open in Side Bar |
|
| Muse Code: Open in New Window |
|
| Muse Code: Open in Terminal |
Cmd/Ctrl+Escape when museCode.useTerminal is on |
| Muse Code: New Conversation |
Cmd/Ctrl+N when enabled |
| Muse Code: Resume Past Conversation |
|
| Muse Code: Reopen Closed Session |
Cmd/Ctrl+Shift+T |
| Muse Code: Insert @-Mention Reference |
Alt+K |
| Muse Code: Toggle Focus view |
Ctrl+Alt+F |
| Muse Code: Create Worktree |
|
| Muse Code: Accept / Reject Proposed Changes |
editor title buttons while viewing a diff |
| Muse Code: Login / Logout |
|
| Muse Code: Show Logs |
|
Inside the chat: Enter sends, Shift+Enter inserts a newline, Esc interrupts, Shift+Tab cycles the approval mode, ↑ recalls previous prompts.
Settings
| Setting |
Description |
museCode.executablePath |
Path to the muse executable. A bare name (default muse) is resolved via PATH, common install dirs, and your login shell; ~ is expanded. |
museCode.environmentVariables |
Extra environment variables for the Muse process. |
museCode.useTerminal |
Run the muse TUI in a terminal instead of the native UI. |
museCode.initialApprovalMode |
onRequest, promptUnmatched, denyUnmatched or allowAll for new conversations. |
museCode.allowDangerouslyAllowAll |
Permit the allowAll mode (never asks). Sandboxes only. Picking "Allow all" in the mode picker offers to turn this on after a confirmation. |
museCode.autoApproveLowRisk |
Smart auto-approve for low-impact approvals (default off): read-only file access is approved automatically, once-only scope, never widened. Everything else still asks. Unknown subjects are never auto-approved. |
museCode.judgeReview |
Second-opinion risk screen in front of auto-approve (default on): a local deterministic review can veto a proposed auto-approval and force human review. It can never approve anything itself. |
museCode.slashSkillScopes |
Which Muse skills show up as / commands: any of project, user, plugin, bundled (default: all but bundled). |
museCode.model / museCode.reasoningEffort |
Defaults for new conversations. |
museCode.autosave |
Save all files before each prompt. |
museCode.focusView |
Hide tool calls and reasoning; show only prompts and replies. |
museCode.showInlineDiffs |
Show each file edit as an inline diff in the chat (default on). |
museCode.sendWhileRunning |
steer (default): a message sent while Muse is working goes straight into the running turn; queue: it waits and starts a new turn afterwards. |
museCode.useCtrlEnterToSend |
Send with Ctrl/Cmd+Enter so Enter inserts newlines. |
museCode.preferredLocation |
panel (editor tab) or sidebar. |
museCode.includeEditorContext |
Attach the active file and selection to prompts. |
museCode.respectGitIgnore |
Respect .gitignore in the @-mention file picker. |
museCode.hideOnboarding |
Hide the welcome checklist. |
How it works
The extension launches muse serve, the Muse Session Protocol (MSP) host, once per workspace folder and talks to it over newline-delimited JSON-RPC on stdio. Sessions, turns, streaming items, approvals and user-input prompts are all MSP objects; the TypeScript types in src/msp/msp.d.ts are generated by muse schema generate-ts and can be regenerated for a newer CLI.
Approval modes map directly onto Muse's: On request (ask when a tool requests it), Prompt unmatched (ask for anything no policy already allows), Deny unmatched, and Allow all.
Smart auto-approve (museCode.autoApproveLowRisk)
There is no risk-aware mode in Muse itself — the four modes above are all-or-nothing per policy match. This extension adds an optional client-side middle ground (off by default): when an approval arrives for read-only file access and the server offers an approve-once choice, the extension takes it immediately and shows a toast instead of a card. The rules are fail-closed:
- only
fileAccess + access: read subjects; shell, network, process, writes, and unknown subject kinds always ask (per MSP SS5.2, unknown kinds are never auto-approved);
- only a server-offered
approved + once choice is used — the scope is never widened to session/always;
- if the decide call fails, the normal approval card appears as fallback.
Second-opinion review (museCode.judgeReview, default on)
The CLI's own LLM approval judge (--approval-judge, default on) has no toggle over MSP/serve, so the extension ships a local deterministic second opinion instead (src/judge.ts). When auto-approve proposes an approval, the review screens judgeEscalated, protectedWrite, the subject, the tool name, and the raw args (destructive commands, pipe-to-shell, obfuscated PowerShell, possible credentials, path traversal, sensitive system paths). A hit vetoes the auto-approval: the normal card appears plus a warning toast naming the reason. It never approves — it only adds friction. Turn it off with museCode.judgeReview: false if you want raw auto-approve.
Muse CLI 1.2.1 changes
The extension targets CLI 1.2.1 (regenerate the types with muse schema generate-ts --out src/msp after upgrading muse):
- Server-initiated requests: CLI 1.2.1 delivers approvals and user-input prompts as
approval/request / userInput/request calls that must be answered with a presentation receipt ({}); the decision/answer still travels as approval/decide / userInput/answer. The extension answers the receipt and fans the request out like the notification channel, so older notification-only flows keep working too.
- Windows: a resolved
muse.cmd launcher shim is mapped to its versioned muse-bin-<ver>.exe (via the sibling .muse-version file), because Node cannot spawn .cmd files without a shell.
Prefer the terminal?
Set museCode.useTerminal to true. The Muse icon and Cmd/Ctrl+Escape then open the muse TUI in an integrated terminal, and Cmd/Ctrl+Alt+K types an @file#L1-2 reference for the current selection into it.
Development
npm install
npm run build # or: npm run watch
# Press F5 in VS Code to launch the Extension Development Host
npm run package # produces muse-code-<version>.vsix
Regenerate the protocol types after upgrading muse:
muse schema generate-ts --out src/msp
Acknowledgements
Inspired by the Claude Code VS Code extension by Anthropic. Muse Code is a product of Meta. This is an independent community project released under the MIT license.
