Muse Code, Cursor, and Copilot — The Coding Assistant Landscape, Updated October 2026

Checked 1 October 2026: Meta's current Muse Code setup guide lists the default model as Muse Spark 1.2 and says workflow features depend on build and rollout. Meta's 24 September recap separately describes Muse Code as out of beta, multi-agent by default and available on Windows, and promotes Muse Spark 1.3 for complex coding and agentic workflows. Verify the model and feature rollout in your installation.

Meta Connect update (24 September 2026). Meta announced Muse Code out of beta, Windows support and multi-agent-by-default behavior. The model selected by an installation can vary: Meta's current setup guide lists Muse Spark 1.2 as the default, while its Connect recap describes Spark 1.3 for coding and agentic workflows.

The coding-assistant market is no longer a two-horse race between an AI-native editor and a cross-editor plugin. The shapes are still own IDE, plugin, and terminal agent. The terminal-agent shelf is now crowded: Claude Code, OpenAI Codex, Grok Build, and now a generally available Muse Code. That does not collapse the decision into a single winner. It makes the workflow question sharper.

Three shapes, three trade-offs

Cursor (harness profile) replaces your editor. It is a VS Code-based editor with assistance woven through its editing surfaces. Whether its included usage and on-demand billing suit the team depends on the current plan and usage; check the live pricing page before buying.

GitHub Copilot (harness profile) still meets you where you are. It runs across VS Code, JetBrains, Visual Studio, Xcode, and Neovim, and has grown beyond inline completion into agent mode and a cloud agent. For mixed-editor teams and procurement-led rollouts, that breadth is the product, not a single model headline. Since June every Copilot plan bills model usage in GitHub AI Credits, with code completions still unlimited on paid plans.

Terminal agents delegate work rather than assist typing. Claude Code, Codex and Grok Build were already on this shelf. Muse Code joined it properly in September:

• It is out of beta as of 24 September, and runs on macOS, Linux and Windows.
• Meta describes Muse Code as multi-agent by default for long-horizon engineering tasks, with parallel workers in isolated workspaces. The current setup docs say workflow orchestration depends on the installed build and rollout; confirm those features are enabled in your environment.
• It is a terminal and CI agent, so it can fit alongside an existing editor. The current first-run docs list muse-spark-1.2 as the default model; check model configuration rather than assuming every install defaults to Spark 1.3.
• Meta's September Connect recap describes Muse Spark 1.3 as supporting complex coding and agentic workflows. Model choice and API billing are separate configuration decisions; check the account's current pricing and data-use terms.

What changed since August

Muse Code went GA. At Meta Connect on 24 September, Meta said Muse Code was out of beta and available on Windows; current setup docs list macOS, Linux and Windows. Meta also said Meta Model API was generally available globally. The current Muse Code setup docs list Muse Spark 1.2 as the default model, while Meta's recap promotes Muse Spark 1.3 for coding and agentic workflows. Confirm the model, account and billing mode in the current docs before estimating cost. The Muse Code harness page carries current pricing details.

Grok 4.7 landed in Grok Build and Cursor on 21 September at $2/$6 per million tokens, the same price as Grok 4.6. xAI positions it on CursorBench 4.0 price-performance.

Codex gained GPT-6 Sol and Luna on 22 September for Plus, Pro, Business, Enterprise and Edu users, with lower API rates for teams that bill Codex usage through the API: Sol's $2/$10 halves GPT-5.6 Sol's promotional $4/$20; Luna's $0.10/$0.50 halves input and lowers output from $1.20 to $0.50.

Microsoft announced a "Code" capability in the new Copilot app on 25 September. This one is easy to misread. Microsoft pitches Code at people who are not developers, who want to build small apps, dashboards and automations inside Microsoft 365. It runs on the same underlying technology as GitHub Copilot. Microsoft says developers continue to use GitHub Copilot day to day. It is not a new option for this shortlist.

Copilot's own fit has not changed. It remains the default answer when the constraint is "we cannot standardise on one editor." Cursor remains the default when the constraint is "we can, and we want the highest in-editor ceiling."

The question that still decides it

Ask what you want the assistant to be doing while you are not watching.

If the honest answer is nothing (faster typing, better completion, fewer documentation detours), a terminal agent is the wrong purchase. Cursor or Copilot will serve you better, and the choice between them is still whether everyone can move to one editor.

If the answer is working through a scoped refactor across many files while I review diffs, that is delegation, and all four terminal agents compete for it. The differences are ecosystem and billing: Anthropic subscriptions or API (Claude Code), ChatGPT plans or the OpenAI API (Codex), xAI (Grok Build), or Meta subscriptions or the Meta Model API (Muse Code). The site's Cursor vs Muse Code switch guide frames the core trade-off: editor-native speed versus terminal delegation.

How to evaluate without a fake leaderboard

Do not rank these on a single score. The catalog keeps harness benchmarks empty where public harnesses diverge from vendor claims, because a wrong agent benchmark does more damage than a missing one. Model boards such as CursorBench measure models inside one harness, not the harnesses themselves.

Instead, run the same three tasks on each candidate you are seriously considering: a small bug fix, a cross-file feature, and a dependency or API migration. Measure time to first correct patch, review effort, and whether anyone still has the tool open after week four. The AI coding task guide walks through model-versus-harness separation. The AI Coding Assistant Finder scores autonomy, editor fit, and rollout constraints in four questions.

A practical shortlist (product facts checked 1 October 2026)

• Mixed editors, enterprise familiarity: start with GitHub Copilot.
• Uniform VS Code culture, in-editor ceiling: start with Cursor.
• Terminal delegation on an Anthropic or OpenAI stack: Claude Code or OpenAI Codex.
• Terminal delegation with parallel workers, or a Meta Model API account: pilot Muse Code, now GA, against your existing agent rather than against Copilot autocomplete.
• Terminal delegation on xAI models: Grok Build with Grok 4.7.

The landscape is wider. The decision logic is the same: pick the shape that matches how your team actually works, then choose the model inside that harness on your own acceptance tests.

Sources (checked 2026-10-01 unless noted)

• Meta for Developers — Meta Connect 2026 recap (Muse Code out of beta, Windows, multi-agent by default; Muse Spark 1.3; Meta Model API GA; Muse Glimmer): https://developers.meta.com/blog/meta-connect-recap/
• Meta Model API — Muse Code setup guide (first-run default model, OS support, conditional workflows): https://dev.meta.ai/docs/muse-code — accessed 2026-10-01.
• Axios — "Meta debuts Muse Spark 1.3" (2 Sep 2026; same price as 1.2; rolls out in Muse Code): https://www.axios.com/2026/09/02/meta-debuts-muse-spark-13-as-personal-agent-work-continues
• Meta AI Research — Introducing Muse Code and Muse Spark 1.2 (5 Aug 2026 beta launch): https://research.meta.ai/blog/introducing-muse-code-and-muse-spark-1-2
• xAI — Introducing Grok 4.7 (21 Sep 2026; Cursor and Grok Build; $2/$6): https://x.ai/news/grok-4-7
• OpenAI — Introducing GPT-6 Sol and Luna (22 Sep 2026; ChatGPT Work and Codex): https://openai.com/index/introducing-gpt-6-sol-and-luna/
• Microsoft — Introducing the new Copilot with Home, Code and Autopilot (25 Sep 2026): https://blogs.microsoft.com/blog/2026/09/25/introducing-the-new-copilot-with-home-code-and-autopilot/
• Cursor — Pricing (included usage, on-demand billed in arrears): https://cursor.com/pricing
• GitHub Docs — Plans for GitHub Copilot (AI Credits by plan): https://docs.github.com/en/copilot/get-started/plans