Muse Spark 1.2
Released Aug 5, 2026 · knowledge cutoff unpublished
- Status
- Unknown
- Location
- United States
- Type
- LLM
- Modality
- Multimodal
- Context window
- 1M
- Max output
- 131K
- Speed (xhigh effort)
- 165 tok/s · 26s to first answer token
- Price ($/MTok in / out)
- $1.25 / $4.25
- Cost per task (xhigh effort)
- $0.40
- Open weights
- No
Benchmarks2 of 10 reported
Terminal-Bench 2.1
LMArena Elo
MMLU-Proretired
GPQA Diamond
SWE-bench Verified
SWE-bench Pro
AIME (latest)retired
Humanity's Last Exam
GDPval-AA v2
ARC-AGI-2
Strengths & weaknesses
Strengths
- Built for multi-agent workflows — plans and delegates as a main agent, or runs in parallel as a subagent, with structured output and parallel function calling across coding harnesses
- Coding-focused retrain shows in whole-repository work — holds dependency graphs and legacy code together across the long context window better than 1.1 did
- Ships alongside Muse Code, a purpose-built terminal coding agent co-trained with the model rather than bolted on after release
Weaknesses
- Reasoning can't be switched off, and the coding-focused retrain cost latency — time to first token runs roughly nine times longer than 1.1, trading speed for the index gain
- Agentic knowledge work — the gap Meta itself flagged in 1.1 — narrows but still trails the frontier
Terminal-Bench 2.1 score of 82.9% was measured running inside Muse Code, the paired coding agent Meta shipped alongside it, rather than the generic harness used for 1.1's SWE-bench Pro figure, so the two releases aren't directly comparable; GPQA Diamond, MMLU-Pro, AIME, HLE, and ARC-AGI-2 were not published for this release, and knowledge cutoff remains undisclosed. Meta's own announcement calls Muse Spark 1.1 'its predecessor,' the basis for predecessorId. LMArena Elo 1498 is the Muse Spark 1.2 (xHigh) text-arena listing, #4 per Arena's own announcement (benchmarklist.com reproduces it as 1498.33).
For developers
API model strings
- meta
muse-spark-1.2
Licence
Proprietary — weights not released
Retirement
No retirement announced
Lineage
Replaces Muse Spark 1.1