# LongCat-Flash-Lite-Sparse vs Mellum2.1-12B-A2.5B-Thinking

> Side-by-side benchmark comparison for LongCat-Flash-Lite-Sparse and Mellum2.1-12B-A2.5B-Thinking across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/longcat-flash-lite-sparse-vs-mellum2-1-12b-a2-5b-thinking
- Last updated: October 8, 2026

- Shared sourced benchmarks: 3
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: LongCat-Flash-Lite-Sparse and Mellum2.1-12B-A2.5B-Thinking share only 3 sourced benchmark rows.

## Summary

- Only 3 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- LongCat-Flash-Lite-Sparse has the larger published context window at 1M.

## Model Snapshot

| Property | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking |
|----------|----------|----------|
| Creator | Meituan | JetBrains |
| Type | Open Weight | Open Weight |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 128K |
| Independent public score (not head-to-head) | null | null |
| Benchmarks Covered | 17 | 7 |
| Pricing (input/output) | $0.00 / $0.00 | $0.00 / $0.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- LongCat-Flash-Lite-Sparse public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 33.7% | Coming soon | Coming soon |
| VITA-Bench | 21.7% | Coming soon | Coming soon |
| MCP Atlas | 45.6% | Coming soon | Coming soon |
| BrowseComp | 48.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 17.4% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- LongCat-Flash-Lite-Sparse public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 68.2% | 47% | LongCat-Flash-Lite-Sparse |
| SWE-bench Pro | 40.6% | 28% | LongCat-Flash-Lite-Sparse |
| SWE Multilingual | 59.3% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 33.7% | Coming soon | Coming soon |
| LiveCodeBench v6 | Coming soon | 82.0% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- LongCat-Flash-Lite-Sparse public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| MMLU | 85.3% | Coming soon | Coming soon |
| MMLU-Pro | 79.2% | Coming soon | Coming soon |
| CMMLU | 84.3% | Coming soon | Coming soon |
| C-Eval | 85.8% | Coming soon | Coming soon |
| GPQA-D | 69.5% | 64.6% | LongCat-Flash-Lite-Sparse |
| MMLU-Redux | Coming soon | 87.8% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- LongCat-Flash-Lite-Sparse public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| IFEval | Coming soon | 90.6% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- LongCat-Flash-Lite-Sparse public-lane score: Coming soon
- Mellum2.1-12B-A2.5B-Thinking public-lane score: Coming soon

| Benchmark | LongCat-Flash-Lite-Sparse | Mellum2.1-12B-A2.5B-Thinking | Winner |
|-----------|-----------|-----------|--------|
| MATH-500 | 95.8% | Coming soon | Coming soon |
| AIME26 | 65.7% | Coming soon | Coming soon |
| HMMT Feb 2026 | 40.5% | Coming soon | Coming soon |
| IMOAnswerBench | 49.4% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between LongCat-Flash-Lite-Sparse and Mellum2.1-12B-A2.5B-Thinking?

Not yet. The models share only 3 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [LongCat-Flash-Lite-Sparse vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-longcat-flash-lite-sparse)
- [Mellum2.1-12B-A2.5B-Thinking vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mellum2-1-12b-a2-5b-thinking)
- [LongCat-Flash-Lite-Sparse vs GPT-6 Astra](/compare/gpt-6-astra-vs-longcat-flash-lite-sparse)
- [Mellum2.1-12B-A2.5B-Thinking vs GPT-6 Astra](/compare/gpt-6-astra-vs-mellum2-1-12b-a2-5b-thinking)

## Explore More

- [LongCat-Flash-Lite-Sparse profile](/models/longcat-flash-lite-sparse)
- [Mellum2.1-12B-A2.5B-Thinking profile](/models/mellum2-1-12b-a2-5b-thinking)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)