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Mellum2-12B-A2.5B-Instruct

JetBrainsCurrentReleased May 28, 2026
Overall Score
Unranked
Arena Elo
N/A
Categories Ranked
1of 8
Price (1M tokens)
N/A
Speed
N/A
Context
128K
Open WeightSelf-hostNon-Reasoning
Confidence
instruct

BenchLM is tracking Mellum2-12B-A2.5B-Instruct, but this profile is currently excluded from the public leaderboard because it still lacks enough non-generated benchmark coverage to rank safely. Only non-generated public benchmark rows appear below.

Mellum2-12B-A2.5B-Instruct is a open weight model with a 128K token context window. It processes queries without explicit chain-of-thought reasoning, offering faster response times and lower token usage.

Mellum2-12B-A2.5B-Instruct sits inside the Mellum2 12B-A2.5B family alongside Mellum2-12B-A2.5B-Thinking. This profile currently has 6 of 236 tracked benchmarks. BenchLM only exposes non-generated benchmark rows publicly, so missing categories stay blank until a sourced evaluation is available.

Its strongest category is Instruction Following (#108). This performance profile makes it a well-rounded choice across a range of tasks.

Ranking Distribution

Category rank across 3 benchmark categories — sorted by best rank

Category Performance

Scores across all benchmark categories (0-100 scale)

Category Breakdown

Agentic

0.0/ 100
Weight: 22%1 benchmark
Terminal-Bench 2.0BrowseCompOSWorld-VerifiedGAIATAU-benchWebArena

Coding

30.7/ 100
Weight: 20%1 benchmark
SWE-bench VerifiedLiveCodeBenchSWE-bench ProSWE-RebenchSciCode

Reasoning

0.0/ 100
Weight: 17%0 benchmarks
MuSRLongBench v2MRCRv2ARC-AGI-2

Knowledge

17.2/ 100
Weight: 12%3 benchmarks
GPQASuperGPQAMMLU-ProHLEFrontierScienceSimpleQA

Math

0.0/ 100
Weight: 5%0 benchmarks
AIME 2025BRUMO 2025MATH-500FrontierMath

Multilingual

0.0/ 100
Weight: 7%0 benchmarks
MGSMMMLU-ProX

Multimodal

0.0/ 100
Weight: 12%0 benchmarks
MMMU-ProOfficeQA ProCharXivCharXiv w/o tools

Inst. Following

#108
32.2/ 100
Weight: 5%1 benchmark
IFEvalIFBench

Benchmark Details

Only benchmark rows with an attached exact-source record are shown here. Source-unverified manual rows and generated rows are hidden from model pages.

Mellum2 12B-A2.5B Family

Instruct

Frequently Asked Questions

How does Mellum2-12B-A2.5B-Instruct perform overall in AI benchmarks?

Mellum2-12B-A2.5B-Instruct has 6 published benchmark scores on BenchLM, but it does not yet have enough non-generated coverage to receive a global overall rank.

Is Mellum2-12B-A2.5B-Instruct good for knowledge and understanding?

Mellum2-12B-A2.5B-Instruct has visible benchmark coverage in knowledge and understanding, but BenchLM does not currently assign it a global category rank there.

Is Mellum2-12B-A2.5B-Instruct good for coding and programming?

Mellum2-12B-A2.5B-Instruct has visible benchmark coverage in coding and programming, but BenchLM does not currently assign it a global category rank there.

Is Mellum2-12B-A2.5B-Instruct good for agentic tool use and computer tasks?

Mellum2-12B-A2.5B-Instruct has visible benchmark coverage in agentic tool use and computer tasks, but BenchLM does not currently assign it a global category rank there.

Is Mellum2-12B-A2.5B-Instruct good for instruction following?

Mellum2-12B-A2.5B-Instruct ranks #108 out of 122 models in instruction following benchmarks with an average score of 32.2. There are stronger options in this category.

Is Mellum2-12B-A2.5B-Instruct open source?

Yes, Mellum2-12B-A2.5B-Instruct is an open weight model created by JetBrains, meaning it can be downloaded and run locally or fine-tuned for specific use cases.

Which sibling models are related to Mellum2-12B-A2.5B-Instruct?

Mellum2-12B-A2.5B-Instruct belongs to the Mellum2 12B-A2.5B family. Related variants on BenchLM include Mellum2-12B-A2.5B-Thinking.

Does Mellum2-12B-A2.5B-Instruct have full benchmark coverage on BenchLM?

Not yet. Mellum2-12B-A2.5B-Instruct currently has 6 published benchmark scores out of the 236 benchmarks BenchLM tracks. BenchLM only exposes non-generated public benchmark rows, so missing categories stay blank until a sourced evaluation is available.

What is the context window size of Mellum2-12B-A2.5B-Instruct?

Mellum2-12B-A2.5B-Instruct has a context window of 128K, which determines how much text it can process in a single interaction.

Last updated: June 8, 2026 · Runtime metrics stay blank until BenchLM has a sourced snapshot.

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