Meta releases Muse Spark 1.3 with max reasoning for long-horizon agentic work
On 2026-09-02 Meta Superintelligence Labs released Muse Spark 1.3 on Muse Code and the Meta Model API (`muse-spark-1.3`). It adds a max reasoning setting and is tuned for long, multi-workflow agentic threads. Meta says it uses ~20% fewer tool calls and ~25% fewer tokens than 1.2 on coding and is more robust to prompt injection. Meta repeated that Muse Spark open weights and bigger models are on its roadmap.
Key facts
- Released 2026-09-02 on Muse Code and the Meta Model API, with 'max reasoning' for hard reasoning and agentic tasks
- Asks clarifying questions, asks the user for help when stuck, and confirms before consequential actions
- Coding vs Muse Spark 1.2 (Meta engineers' comparisons): ~20% fewer tool calls, ~25% fewer tokens, less verbose
- Safety: stronger resistance to adversarial inputs and prompt injection; better calibration on irreversible actions
- API list price $1.25 input / $4.25 output per 1M tokens; 1M context, 200K max output; cheaper '-contributor' tier (see model file)
- Roadmap per Meta: 'bigger models, the Muse Spark open weights release, and more'
What happened
Meta released Muse Spark 1.3 one month after 1.2. The update targets long agentic work: the model builds its own context from messy, conflicting sources, keeps track of several workflows in one long thread, follows long instructions without dropping constraints, and is trained across many harnesses. It is also trained to know better what it cannot do, so it reports blockers instead of hallucinating results. It went live the same day in Muse Code and the Meta Model API.
Why it matters
Muse Spark 1.3 is the model generation that shipped just before Meta's consumer Muse agent (Sept 8), and it is what developers can call directly. Meta again promised open weights for Muse Spark but gave no date.
The pricing and context numbers come from Meta's developer pages (see data/models/muse-spark-1-3.md). Meta's blog gives no headline benchmark numbers.
Changelog
- 2026-09-30: created (the model file existed but there was no timeline entry)
Models
- Muse Spark 1.3 Meta · current
Related events
- Meta launches Muse Code terminal coding agent powered by Muse Spark 1.2 ★★★
- Meta releases Muse Spark 1.1 and opens the Meta Model API public preview ★★★
- Meta launches Muse, a free consumer personal AI agent ★★★★
Sources (4)
- officialMeta AI - Introducing Muse Spark 1.3
- paperMeta - Muse Spark 1.3 multimodal evaluation methodology
- docsMeta Model API - Muse Spark model page
- officialMeta for Developers on X
id: 2026-09-02-meta-muse-spark-1-3 · updated 2026-09-30 · open in the interactive timeline