Muse Spark 1.3
by Meta
Meta’s fourth Muse Spark release in five months — an agentic-coding update over
Muse Spark 1.2 that cuts tool calls by ~20% and tokens by ~25% on
comparable coding tasks, with a max reasoning mode positioned at the frontier.
Part of the Meta Muse family — succeeds Muse Spark 1.2 as the coding-tuned
frontier variant.
Specs & positioning
- Released 2026-09-02; benchmarked by Meta against Muse Spark 1.2, GPT-5.6 Sol (max), and
Opus 5 (max) across agent, coding, instruction-following, and long-context evaluations - ~20% fewer tool calls and ~25% fewer tokens than Muse Spark 1.2 on comparable coding tasks
(Meta engineer comparisons) - Improved long-horizon task management, multitasking, prompt-to-task mapping accuracy, and
self-awareness of its own capabilities/limitations - Stronger adversarial robustness — more resistant to prompt injection
- Trained across a diverse set of harnesses to reduce constraint drift on complex, multi-step tasks
- Max reasoning mode available at launch (more compute-intensive; Meta notes it remains
limited pending further safety testing) - Pricing unchanged from 1.2: 4.25 / million output tokens
Availability
- Muse Code (macOS and Linux) — see Muse Code
- Meta Model API
- Rolling out to Meta AI, Instagram, and Facebook
Timeline
| Date | Event |
|---|---|
| 2026-08-06 | Muse Spark 1.2 launches, powering Muse Code |
| 2026-09-02 | Muse Spark 1.3 launches — 4th Muse Spark release in 5 months |
Related
- Meta Muse — series hub (Spark, Glimmer, Code, Image, Video)
- Muse Spark 1.2 — the version it supersedes
- Muse Code — the coding agent it powers