Model record · checked 06 Aug 2026
Muse Spark 1.2 is the model, not the agent.
Meta describes Muse Spark 1.2 as a coding-focused update optimized for multi-file refactors, complex debugging, whole-repository context, and long-running agent workflows.
01 · Identity
The inference layer under Muse Code.
Muse Code supplies the terminal runtime, tools, state, approvals, agents, and event log. Muse Spark 1.2 supplies model outputs. Meta says the model was co-trained with the harness but also generalized across other coding agents.
- Standard model ID
muse-spark-1.2- Contributor model ID
muse-spark-1.2-contributor- Context window
- 1M tokens Meta says
- Access
- Muse Code, Meta Model API, and OpenRouter as listed by Meta
- Release date
- 05 Aug 2026
02 · Pricing snapshot
| Tier | Cached input | Input | Output | Data / access qualification |
|---|---|---|---|---|
| Standard | $0.15 / 1M | $1.25 / 1M | $4.25 / 1M | Meta says prompts and completions are not used to train its models; zero-data-retention requests are beginning through sales. |
| Contributor | See current Meta terms | See current Meta terms | See current Meta terms | Token-rate-limited in a rolling five-hour window, select countries, and data may be used to improve Meta products. |
Reasoning tokens are billed as output, according to Meta’s launch guide. This site does not estimate cost per task without a reproducible workload.
03 · Training claims
Co-trained for the harness around it.
Meta says training included rejection-sampled harness trajectories and recipe optimization for goals, compaction, and subagents. Long-horizon training covered whole-repository generation, large end-to-end projects, and auto-research.
co-training harness trajectories
conditioning goals + planning
memory context compaction
workloads whole repositories
Qualification:
These are Meta’s training descriptions.
No weights, training corpus, or independent
reproduction is supplied by this site.
04 · Evaluation limits
Compare configurations, not logos.
A coding score belongs to a model, harness, effort setting, environment, date, and budget. Meta’s charts are useful release evidence; they do not substitute for an independent workload on your repository.