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Claude Sonnet 4.6 vs GPT-5-Codex

2 vs 0 benchmarks won

Anthropic
Claude Sonnet 4.6
OpenAI
GPT-5-Codex
Overview
CompanyAnthropicOpenAI
Release dateFeb 17 2026Sep 15 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
89.9%
Software engineering
SWE-Bench Verified
79.6%
Multimodal understanding
MMMU
Timeline
Release gapGPT-5-Codex shipped 155 days before Claude Sonnet 4.6

Which is better: Claude Sonnet 4.6 or GPT-5-Codex?

Claude Sonnet 4.6 leads GPT-5-Codex on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). GPT-5-Codex shipped 155 days before Claude Sonnet 4.6, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude Sonnet 4.6 released?
Claude Sonnet 4.6 was released by Anthropic on Feb 17 2026.
When was GPT-5-Codex released?
GPT-5-Codex was released by OpenAI on Sep 15 2025.

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