Mellum2 12B
Released
2026-06-01
Last refreshed
2026-10-08
Status
Researched 135d ago
Open sourceCommercial use: permittedCodingRAGAgentsLong contextJSON / Tool use
Mellum2 12B is a released coding, rag, and agents model with open-source and 128K context; evaluate it while provider pricing coverage matures.
JetBrains releases · 2 in the last 12 monthsChangelog →
Specifications
- Family
- Mellum 2
- Released
- 2026-06-01
- Context
- 128K
- Parameters
- 12B (2.5B active)
- Architecture
- Mixture of Experts
- Specialization
- code
- Openness
- Open source
- License
- Apache 2.0OSI-approvedCommercial use: permitted
- Weights
- Available
- Code
- Unknown
- Training
- Pretrained
Created by
Pricing
No tracked provider token pricing is available yet.
Links
About
Mellum2 12B is JetBrains' open-weights mixture-of-experts model for software engineering workflows. It has 12B total parameters, activates about 2.5B parameters per token, and supports long-context coding, tool use, function calling, reasoning, and agentic assistance.
Providers
No active provider routes are tracked for this model yet.
Capabilities
ReasoningJSON / Tool use
Benchmark peer barsfor Coding
HumanEvalRank 46 of 99
Benchmark scores(2)
Scores are benchmark-specific and are direction-aware: the same numeric gap can mean very different outcomes across suites. Use the leaderboard context and this model's provider route to decide whether the winning margin is meaningful for your workload.
| Benchmark | Score | Version | Evaluation | Source |
|---|---|---|---|---|
| Berkeley Function Calling Leaderboard v3 | 66.3 | BFCL v3 (accuracy%)Observed 2026-06-07 | — | Source |
| HumanEval | 78.4 | HumanEval (pass@1)Observed 2026-06-07 | — | Source |
Migration checks
No linked migration route is available for this model yet.
Created by
Pricing
No tracked provider token pricing is available yet.
Links