Local background agents vs cloud tasks
Muse Code's background agents run on your own machine, so a session stays alive instead of re-gathering context. Codex reportedly runs those tasks in the cloud, surviving a closed laptop.
Muse Code vs Codex: the quick verdict
The short answer: Muse Code vs Codex turns on access and surfaces, not on model quality.
Pick Muse Code if you work in a macOS or Linux terminal, want the lowest per-token price from a frontier lab, and accept attaching a payment method first. Pick Codex if you want a free tier, a subscription that also covers ChatGPT, cloud agents that survive a closed laptop, or an agent reachable from an IDE, Slack or a phone. Reported scores sit within a point, so Muse Code vs Codex is no capability shootout.
Choose Muse Code when
- Cost per token binds: Contributor is $0.10 / $0.20 per M.
- You need the 1M-token multimodal context of Muse Spark 1.2.
- Replay-exact restarts beat a GUI.
Choose Codex when
- You want to try before paying — Muse Code has no free tier (Muse Code pricing).
- You are on Windows, or need work to continue in the cloud.
- Your team already pays for ChatGPT.
Wider field: best AI coding agents, Muse Code alternatives.
18-point comparison matrix
Every dimension we can source, Muse Code on the left, OpenAI's Codex on the right.
| Dimension | Muse Code | OpenAI Codex |
|---|---|---|
| Vendor | Meta Superintelligence Labs | OpenAI |
| Default models | Muse Spark 1.2 | GPT-5.6 Sol / Terra / Luna |
| Context window | 1M tokens | Not sourced |
| Multimodal input | Images, video, PDF | Not sourced |
| Surfaces | Terminal only | CLI, IDE, cloud, Slack, iOS |
| Cloud or async agents | Local background agents | Cloud async tasks |
| Native Windows | No — four macOS/Linux binaries | Unconfirmed; WSL historically advised |
| Free tier | None | Yes, via ChatGPT plans |
| Entry price | Pure token billing | Go $8 / Plus $20 / Pro $100–200 monthly |
| Per-token price | $1.25 / $4.25 per M | Bundled into the plan |
| Cheapest tier | Contributor $0.10 / $0.20 per M | The free ChatGPT tier |
| Hard spending cap | None; email alerts only | Fixed by subscription |
| Rate limits | 3,000 RPM / 4M TPM; 60 RPM Contributor | Plan-based |
| Session persistence | Append-only event log, replay-exact | Not sourced |
| Skills | /plan, /grill, /goal | Not sourced |
| Hooks and MCP | Community-reported only | Not sourced |
| Trains on your prompts | Standard no; Contributor yes | See OpenAI's policies |
| Maturity | Beta, 5 August 2026 | Established product line |
Prices are as reported. Rows marked "unconfirmed" or "not sourced" are dimensions our sources do not settle. Check Codex details against OpenAI's Codex page and ChatGPT pricing.
Muse Code vs Codex benchmarks: the Terra-not-Sol objection
Muse Code reportedly wins the headline matchup; the opponent Meta picked is the argument.
Meta's self-reported figures (second-hand)
Meta reported Muse Spark 1.2, the model powering Muse Code, at 82.9% on Terminal-Bench 2.1 against GPT-5.6 Terra at 81.8% — a 1.1-point margin — with Claude Opus 5 ahead at 86.7%. These reach us via press coverage of Meta's Muse Code announcement: vendor-reported and second-hand.
The community objection is fair: Terra is not OpenAI's flagship. Sol sits above it and Meta omitted it, so a 1.1-point win over the mid-tier model is weaker than the "beats Codex" framing much coverage used. Commenters on the Hacker News launch thread noted that in Meta's own GPU-kernel study, Muse Code lost to GPT-5.6 Sol.
Artificial Analysis's independent numbers
Artificial Analysis measured Muse Spark 1.2 at 80% on Terminal-Bench v2.1, up from 78% for 1.1, with an Intelligence Index of 54 against 51 and roughly 165 output tokens per second.
Do not mix regimes: 82.9% and 80% describe nominally the same benchmark, and the gap exceeds the margin Meta claims over Terra. With no independent Terra or Sol figure from the same harness, Muse Code vs Codex reads as statistically close, with contested opponent selection.
Muse Code vs Codex pricing: where each becomes cheaper
Token billing versus subscriptions at real volumes, so you can locate your break-even point.
| Monthly agent steps | Muse Code Standard | Muse Code Contributor | Codex Go | Codex Plus |
|---|---|---|---|---|
| 50 | $4.39 | $0.33 | $8 | $20 |
| 100 | $8.78 | $0.66 | $8 | $20 |
| 200 | $17.55 | $1.32 | $8 | $20 |
| 500 | $43.88 | $3.30 | $8 | $20 |
| 1,000 | $87.75 | $6.60 | $8 | $20 |
| 2,000 | $175.50 | $13.20 | $8 | $20 |
| 5,000 | $438.75 | $33.00 | $8 | $20 |
One agent step = 60,000 input plus 3,000 output tokens, no cache hit: $0.0878 on Muse Code Standard, $0.0066 on Contributor. Standard passes the $8 Go plan near 91 steps a month, $20 Plus near 228, a $100 Pro plan near 1,139; Contributor stays under $20 until roughly 3,030. See the Muse Code cost calculator.
Workflow differences that change your day
Three Muse Code vs Codex differences you feel in the first session, none visible in a benchmark table.
An append-only event log
Every Muse Code action lands in a local append-only event log, so a killed session replays exactly rather than resuming from a snapshot. Our sources describe no Codex equivalent.
An uncapped meter vs a plan that stops
Muse Code bills every token with no hard ceiling — email alerts, not a stop. A Codex plan cannot overrun. Workarounds: a virtual card limit or a per-key OpenRouter cap.
Is Muse Code built on the Codex CLI?
A launch-week rumour nobody has substantiated.
Some developers have suggested Muse Code is a fork of OpenAI's Codex CLI. This is unconfirmed: Meta has not addressed it, we have seen no comment from OpenAI, and nobody has published a diff or binary analysis. The public installer shows four hard-coded macOS and Linux targets, a binary named muse in ~/.local/bin and Meta's own OAuth flow — none of which establishes lineage. Architecture: what is Muse Code.
Data policies compared
The cheapest Muse Code tier asks by far the most of you.
Muse Code prices its data terms explicitly, which is unusual. Standard, at $1.25 and $4.25 per million tokens, is stated not to train on your prompts or completions. Contributor drops to $0.10 and $0.20 — a roughly 12.5× input and 21.25× output discount — in exchange for training rights over both, and is country-limited and capped at 60 requests per minute.
OpenAI publishes its own data policies; we link rather than paraphrase: OpenAI's Codex page and ChatGPT pricing. Muse Code is distinctive in handing you that trade as a tier choice. Clause-by-clause: Muse Code privacy; sign-in: how to install Muse Code.
Keep comparing
Where readers of this Muse Code vs Codex comparison usually head next.
- Muse Code vs Claude CodeThe other head-to-head.
- Muse Code pricingBoth tiers, rate limits.
- Muse Code privacyThe Contributor grant.
- Muse Spark APIMeta's API and OpenRouter.
- Muse Code on WindowsThe WSL2 route.
Frequently Asked Questions
Muse Code vs Codex — which one should I pick?
Pick Codex for a free tier, cloud agents or any surface beyond a terminal; pick Muse Code if per-token cost binds and you are on macOS or Linux. Reported scores separate them by about a point, so surfaces and access decide Muse Code vs Codex. Muse Code is still in beta; Codex is established.
Is Muse Code built on the Codex CLI?
Unconfirmed — a launch-week community rumour with no evidence we have seen, addressed by neither Meta nor OpenAI. The launcher installs a binary named muse and authenticates through Meta's own OAuth flow, which says nothing about lineage. We will not assert it either way.
Is Muse Code cheaper than Codex?
Usually, but not always. Muse Code Standard costs roughly $0.088 per 60K-in/3K-out agent step, so it passes an $8 Go plan around 91 steps a month and a $20 Plus plan around 228; above those volumes the subscription wins. Codex also has a free path that Muse Code cannot match.
Does Muse Code have a free tier like Codex?
No. Muse Code has no free quota, no verified trial credits and no subscription — you attach a payment method and pay per token from the first request. Codex is reported to be reachable through free ChatGPT plans. Reports of a $20 signup credit date from the Muse Spark 1.1 era and remain unconfirmed.
Does Muse Spark beat GPT-5.6?
Only against one member of the family, on the vendor's own numbers. Meta reported Muse Spark 1.2 at 82.9% on Terminal-Bench 2.1 against GPT-5.6 Terra at 81.8%, relayed second-hand by press. Terra is not the flagship — Sol is — and Meta did not publish that comparison, the most common criticism of these benchmarks.
Can I run Muse Code on Windows?
Not natively. The launcher ships exactly four binaries — arm64 and x86 on macOS and Linux — and Meta has made no roadmap statement about Windows. WSL2 is the community workaround, complicated by browser-based sign-in; see Muse Code on Windows. Native Windows support for Codex is unconfirmed in our sources, so verify it on OpenAI's docs.
Is Muse Spark the same thing as ChatGPT?
No. Muse Spark 1.2 is Meta's model, trained alongside the Muse Code harness and available through Meta's API and OpenRouter; ChatGPT is OpenAI's assistant product built on the GPT family. Muse Code is the terminal agent wrapped around Muse Spark, roughly as Codex wraps GPT-5.6.
Sources
- Meta AI Research — Introducing Muse Code and Muse Spark 1.2research.meta.ai
- Artificial Analysis — Muse Spark 1.2 independent evaluationartificialanalysis.ai
- OpenAI — Codexdevelopers.openai.com
- OpenAI — ChatGPT pricingdevelopers.openai.com
- Hacker News — Muse Code launch discussionnews.ycombinator.com