Agentic harness comparison
Grok Build vs Muse Code
Compared on where each one runs, which editors it supports, how autonomous it is, and how it bills — the four things that actually decide Grok Build vs Muse Code. Rankings reflect fit and trade-offs, not a single universal winner; partner links, when present, do not replace that methodology.
Details last verified August 14, 2026.
SpaceXAI
Grok Build
Terminal · Agentic
Meta
Muse Code
Terminal · Agentic
| Specification | Grok Build | Muse Code |
|---|---|---|
| Vendor | SpaceXAI | Meta |
| Runs in | Terminal | Terminal |
| Editor support | Any (editor-agnostic) | Any (editor-agnostic) |
| Autonomy | Agentic | Agentic |
| Pricing model | Hybrid | Usage-based |
| Requires changing editor | No | No |
Benchmark scores carry the month they were measured. Values we could not confirm are shown as “Not verified” rather than estimated.
Grok Build
SpaceXAI's terminal coding agent with plan mode and Git-worktree-isolated parallel subagents, now powered by Grok 4.6.
Best for
- Parallel isolated subagents
- Teams already on SuperGrok
- Plan-then-diff workflows
Watch out
x.ai currently advertises Grok Build as available to try for Free; fuller parallel capacity may still sit on higher SuperGrok / X Premium+ tiers. Early product relative to Claude Code. Included usage is 2× for the first week from 2026-08-12 — do not size seats on that promo.
Muse Code
Meta's beta terminal agent powered by Muse Spark 1.2 — persistent async background agents and a restart-safe local event log.
Best for
- Large-repo agentic coding
- Long-running tool loops
- Teams willing to bill Meta Model API usage
Watch out
macOS/Linux beta only; Meta account required. Co-trained for Muse Spark — swapping models is not the product story. Contributor pricing trains on your usage and carries lower RPM than standard API rates.
Common questions
Grok Build vs Muse Code
Answered from the verified figures on this page rather than general guidance.
Do I have to change editor to use Grok Build or Muse Code?
Neither does. Grok Build runs in the terminal alongside any editor and Muse Code runs in the terminal alongside any editor, so people keep the setup they already have.
How are Grok Build and Muse Code priced?
Grok Build is hybrid and Muse Code is usage-based. The headline seat or plan price is not the heavy-agent bill — included credits, shared pools, and overages dominate once you loop agents hard. Estimate cost per successful task and set spend caps. Cost tracks how much you delegate, so set a spending limit before rollout rather than after the first surprise.
Is Grok Build or Muse Code better for large refactors?
Both are agentic, so neither has a structural advantage on delegated work. Judge them on editor fit and price instead.
Will my project rules transfer between Grok Build and Muse Code?
Usually not automatically. Cursor rules, CLAUDE.md, AGENTS.md, and extension-specific configs are different conventions. Keep one source of truth in the repository (commonly AGENTS.md) and copy or link into each tool’s native format so switching does not wipe months of project teaching.
Do coding agents replace code review?
No. Agents can draft patches faster, but they do not remove the need for human review of plans, tool calls, permissions, diffs, tests, and rollback paths. Treat autonomy as a reason for stronger review, not less — see the coding assistant rollout guide at /ai-harnesses/guides/coding-assistant-rollout-guide.
Should we harden MCP before rolling out a coding agent?
Yes for any agent that can install MCP servers or run tools. Maintain a short allowlist, review each server’s folder and network access before install, fail closed on unknown tools, and log tool calls. .cursorignore and similar rules do not block MCP or shell access once a command is approved.
Next step
Which one fits
Autonomy and editor constraints decide this far more reliably than a benchmark score.
If most of your week is small, frequent edits, an assistive workflow beats delegation and an agentic harness sits idle while billing. If you regularly hand over work spanning many files, the reverse is true.
Where one tool requires changing editor and the other does not, that difference usually outweighs any capability gap across a team — rollouts fail on adoption, not capability.
“Open vendor” links use a first-party redirect for click counting. They are not commissionable partner placements unless a programme is active for that vendor. Affiliate disclosure.