Model comparison

Devstral Medium vs GPT-5.6 Luna

GPT-5.6 Luna has enough public results to be ranked (#30); Devstral Medium does not yet, so treat this comparison as directional.

Last verified . 2 shared benchmarks.

Devstral Medium Mistral AI

30.1

Unranked Sparse

GPT-5.6 Luna OpenAI

54.6

Rank #30 Confirmed

Summary

  • They share 2 benchmarks with published results for both. Devstral Medium scores higher in 0 categories and GPT-5.6 Luna in 2 categories; 2 gaps are clear of the uncertainty.
  • The widest gap is in coding, where GPT-5.6 Luna leads 54.5 to 24.3.
  • The biggest single-benchmark swing is Kagi LLM Benchmark: 37.7% for Devstral Medium and 49.1% for GPT-5.6 Luna.
  • GPT-5.6 Luna is cheaper at $0.20 / $1.20 per million input/output tokens, against $0.40 / $2 for Devstral Medium.
  • GPT-5.6 Luna accepts more context: 1.05M tokens versus 262K.
  • Devstral Medium has downloadable open weights; the other is API-only.

Side by side

Devstral Medium and GPT-5.6 Luna specifications
Devstral MediumGPT-5.6 Luna
ProviderMistral AIOpenAI
Noometry Index30.154.6
Released2025-07-102026-07-09
WeightsOpenProprietary
Context window262K1.05M
Max output262K128K
Input $ / M tokens$0.40$0.20
Output $ / M tokens$2$1.20
Results tracked252

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Category by category

Coding GPT-5.6 Luna leads

Devstral Medium: 24.3, GPT-5.6 Luna: 54.5 (#28)

Coding benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena WebDev10761519
DeepSWE—67.2%
FrontierCode—39.8%
CursorBench—35.9%
SciCode—53.6%
WeirdML—60.9%
LMArena Coding—1466
ALE-Bench—1,667

Agentic & Tool Use Not comparable

Devstral Medium: —, GPT-5.6 Luna: 34.4 (#45)

Agentic & Tool Use benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
APEX-Agents—43%
BALROG—45.6%
GDP.pdf—22.7%
Vending-Bench 2—4,095

Reasoning GPT-5.6 Luna leads

Devstral Medium: 21.1, GPT-5.6 Luna: 47.6 (#43)

Reasoning benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
Kagi LLM Benchmark37.7%49.1%
ARC-AGI-2—59.5%
SimpleBench—46.8%
NYT Connections (extended)—69.4%
ARC-AGI-1—88%
CritPt—20.6%
Chess Puzzles—40%
LMArena Hard Prompts—1451
Mystery Game Puzzles—21%
DTBench—89.1%
LMCA—48.5%
Surface Evolver Bench—61.9%
Epoch Capabilities Index—156.39

Math Not comparable

Devstral Medium: —, GPT-5.6 Luna: 77.7 (#14)

Math benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
FrontierMath (Tiers 1-3)—82.1%
FrontierMath Tier 4—61%
OTIS Mock AIME 2024-2025—98.3%
ProofBench—60%
LMArena Math—1458

Knowledge Not comparable

Devstral Medium: —, GPT-5.6 Luna: 58.5 (#34)

Knowledge benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
GPQA Diamond—91.6%
SimpleQA Verified—41%
LMArena Expert—1478

Multimodal Not comparable

Devstral Medium: —, GPT-5.6 Luna: 42.7 (#28)

Multimodal benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena Vision—1258
Blueprint-Bench 2—22.6%
Furniture Assembly—42.5%
LMArena Document—1457

Multilingual Not comparable

Devstral Medium: —, GPT-5.6 Luna: 52.8 (#78)

Multilingual benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena Non-English—1417
LMArena Chinese—1470
LMArena French—1456
LMArena German—1454
LMArena Japanese—1411
LMArena Korean—1415
LMArena Russian—1428
LMArena Spanish—1448

Instruction Following Not comparable

Devstral Medium: —, GPT-5.6 Luna: 75.6 (#57)

Instruction Following benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena Instruction Following—1437

Long Context Not comparable

Devstral Medium: —, GPT-5.6 Luna: 43.9 (#82)

Long Context benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena Longer Query—1436

Writing & Preference Not comparable

Devstral Medium: —, GPT-5.6 Luna: 68.0 (#29)

Writing & Preference benchmarks
BenchmarkDevstral MediumGPT-5.6 Luna
LMArena Text—1431
LMArena Creative Writing—1396
EQ-Bench Creative Writing—1829
EQ-Bench 4—1156
LMArena Multi-Turn—1434

Frequently asked questions

Is Devstral Medium better than GPT-5.6 Luna?

GPT-5.6 Luna has enough public results to be ranked (#30); Devstral Medium does not yet, so treat this comparison as directional.

Which is cheaper, Devstral Medium or GPT-5.6 Luna?

GPT-5.6 Luna is cheaper. It lists at $0.20 per million input tokens and $1.20 per million output tokens; Devstral Medium lists at $0.40 and $2.

Is Devstral Medium or GPT-5.6 Luna better for coding?

GPT-5.6 Luna scores higher on coding benchmarks: 54.5 versus 24.3 in the Noometry coding category.

Which has the bigger context window?

GPT-5.6 Luna does, with 1.05M tokens against 262K.

How many benchmarks do Devstral Medium and GPT-5.6 Luna share?

2 benchmarks have published results for both models. Devstral Medium has 2 scored results on Noometry and GPT-5.6 Luna has 52.

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