muse-delegation

Table of Contents

• [Overview](#overview)
• [When To Use](#when-to-use)
• [When NOT To Use](#when-not-to-use)
• [Prerequisites](#prerequisites)
• [Quick Start](#quick-start)
• [Smart Delegation](#smart-delegation)
• [Muse-Specific Details](#muse-specific-details)
• [Exit Criteria](#exit-criteria)

Muse Code Delegation

Overview

Muse Code is Meta's terminal coding agent, released August 2026 and

built on Muse Spark 1.2. It runs either as an interactive TUI or as a

one-shot headless command, and the headless form is what delegation

uses.

The binary is muse. Meta publishes no npm or PyPI package for it:

the documented install is a script served from Meta's own domain.

When To Use

• delegation-core selected muse for the task
• Repository-scale reading where Muse Spark 1.2's 1M-token context

helps

• Work that should run unattended, since muse exec is designed for

CI

When NOT To Use

• META_API_KEY is unset and the run cannot be interactive
• A specific model must be selected. Meta documents no --model flag

for exec, so the CLI default stands

• Structured output is required. No output-format flag is documented

for exec

Prerequisites

Installation

curl -fsSL https://dev.meta.ai/install.sh | sh

This pipes a remote script into a shell. Read

<https://dev.meta.ai/docs/muse-code> before running it. The guided

installer offers the same command and shows its source first:

make -C plugins/conjure delegate-setup

Authentication

Meta documents the environment variable as the CI path:

export META_API_KEY="<your-key>"
muse exec "Run the test suite and summarize failures."

A bare muse prompts for browser sign-in on first run, which is not

usable unattended. There is no muse auth status command, so the

service declares an empty auth probe and verification checks

META_API_KEY instead.

Quick Start

Using the shared delegation executor

uv run python scripts/delegation_executor.py muse "Summarize this module" \
  --files src/

Through the Makefile

make -C plugins/conjure delegate-muse PROMPT='Explain this design'

Direct CLI usage

muse exec "Explain the retry logic in this package"

Smart Delegation

muse declares the strengths code_execution and large_context,

and ranks behind gemini, qwen, minimax and glm in the candidate order.

It declares no model ids, so smart_delegate leaves model selection

to the CLI rather than passing a flag Meta does not document.

Muse-Specific Details

| Property | Value |

|----------|-------|

| Binary | muse |

| Headless form | muse exec <prompt> |

| Prompt delivery | positional, no flag |

| Version probe | muse --version |

| Auth probe | none published |

| Auth | META_API_KEY |

| File context | inlined, no @path syntax |

The prompt is positional. A command ending in a flag would consume the

prompt as that flag's value, which is why the service config sets

prompt_flag=None and the War Room expert's command ends at

muse exec.

Two claims circulating in third-party guides are not in Meta's own

documentation and are not relied on here: a --json flag streaming

JSONL events to stdout, and muse auth set --api-key-stdin. The

confirmed JSONL reference is to on-disk session logs. Treat both as

unverified until Meta documents them.

Exit Criteria

• [ ] muse resolves on PATH and muse --version answers
• [ ] META_API_KEY is set, or the operator accepted an interactive

sign-in

• [ ] The built command is muse exec <prompt> with the prompt as the

final argument and no prompt flag before it

• [ ] File context was inlined into the prompt rather than passed as

@path references

• [ ] Output saved to delegations/muse/YYYYMMDD_HHMMSS.md
• [ ] This skill ran because delegation-core selected muse, not by

default