Composer 2 vs GPT-OSS 20B

Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.

Composer 2 is clearly ahead on the aggregate, 62 to 35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Composer 2's sharpest advantage is in agentic, where it averages 61.7 against 35.4. The single biggest benchmark swing on the page is React Native Evals, 97.2% to 62.3%.

Composer 2 is also the more expensive model on tokens at $0.50 input / $2.50 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for GPT-OSS 20B. That is roughly Infinityx on output cost alone. Composer 2 is the reasoning model in the pair, while GPT-OSS 20B is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Composer 2 gives you the larger context window at 200K, compared with 128K for GPT-OSS 20B.

Quick Verdict

Pick Composer 2 if you want the stronger benchmark profile. GPT-OSS 20B only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Agentic

Composer 2

Composer 2

61.7

GPT-OSS 20B

35.4

61.7%
Terminal-Bench 2.0
35%
Coming soon
BrowseComp
42%
Coming soon
OSWorld-Verified
31%

Coding

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

73.7%
SWE Multilingual
Coming soon
97.2%
React Native Evals
62.3%
Coming soon
HumanEval
23%
Coming soon
SWE-bench Verified
14%
Coming soon
LiveCodeBench
11%
Coming soon
SWE-bench Pro
18%

Multimodal & Grounded

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

Coming soon
MMMU-Pro
31%
Coming soon
OfficeQA Pro
42%

Reasoning

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

Coming soon
MuSR
27%
Coming soon
BBH
62%
Coming soon
LongBench v2
48%

Knowledge

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

Coming soon
MMLU
85.3%
Coming soon
GPQA
30%
Coming soon
SuperGPQA
28%
Coming soon
HLE
1%
Coming soon
FrontierScience
34%
Coming soon
SimpleQA
29%

Instruction Following

Coming soon

Benchmark data for this category is coming soon.

Multilingual

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

Coming soon
MGSM
61%

Mathematics

Coming soon

Comparable scores for this category are coming soon. One or both models do not have sourced results here yet.

Coming soon
AIME 2023
31%
Coming soon
AIME 2024
33%
Coming soon
AIME 2025
32%
Coming soon
HMMT Feb 2023
27%
Coming soon
HMMT Feb 2024
29%
Coming soon
HMMT Feb 2025
28%
Coming soon
BRUMO 2025
30%

Frequently Asked Questions

Which is better, Composer 2 or GPT-OSS 20B?

Composer 2 is ahead overall, 62 to 35. The biggest single separator in this matchup is React Native Evals, where the scores are 97.2% and 62.3%.

Which is better for agentic tasks, Composer 2 or GPT-OSS 20B?

Composer 2 has the edge for agentic tasks in this comparison, averaging 61.7 versus 35.4. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Last updated: March 18, 2026

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