Claude Sonnet 4.6 vs GPT-5.3-Codex
Anthropic Claude Sonnet 4.6 | OpenAI GPT-5.3-Codex | |
|---|---|---|
| Overview | ||
| Company | Anthropic | OpenAI |
| Release date | Feb 17 2026 | Feb 5 2026 |
| Access | Proprietary | Proprietary |
| Benchmarks | ||
Nonsense detection BullshitBench v2Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | 91%Best | 24% |
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 79.6% | — |
Agentic coding CursorBench v3.1Cursor's own test of harder, real-world coding tasks inside a code editor. Higher is better. | 49% | — |
Next.js coding Next.js EvalsVercel's open eval of how well AI coding agents build and migrate real Next.js apps — measured as the share of tasks the agent completes successfully. Higher is better. | 58% | 83%Best |
Multi-step tool use MCP AtlasCan the AI chain together many tools and steps to complete one bigger task, rather than doing just a single thing? Higher is better. | 69.5% | — |
Multidisciplinary reasoning Humanity's Last Exam · no toolsHumanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better. | 33.2% | — |
Abstract reasoning ARC-AGI-2Puzzle-style tests of abstract reasoning and pattern-finding — the kind of thing people find easy but AIs often struggle with. Higher is better. | 58.3% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 89.9% | — |
Agentic computer use OSWorld-VerifiedCan the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better. | 72.5% | — |
Agentic financial analysis Finance Agent v2Tests the AI on real financial-analysis work, like digging through reports and making sound decisions. Higher is better. | 51% | — |
Knowledge work GDPval-AAMeasures how well the AI does economically valuable knowledge work, judged against human experts. Shown as a rating (like a chess Elo) — higher is better. | 1676 | — |
Chart reasoning CharXiv ReasoningCan the AI read and reason about complex charts and figures, not just text? Higher is better. | 72.4% | — |
Multimodal reasoning MMMU-ProA tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better. | 74.5% | — |
Spatial reasoning Blueprint-Bench 2Can the AI reason about space and layout — for example, understanding a floor plan or blueprint? Higher is better. | 6.7% | — |
Long context MRCR v2 (8-needle) · 128k averageTests whether the AI can find specific details buried inside a very long document (around 128k tokens — roughly a long book). Higher is better. | 84.9% | — |
Community preference (code) Arena Elo (Code)Like the text arena, but people vote on which AI writes better code. The votes become a chess-style Elo rating on arena.ai. Higher is better. | 1521Best | 1406 |
| Timeline | ||
| Release gap | GPT-5.3-Codex shipped 12 days before Claude Sonnet 4.6 | |
Which is better: Claude Sonnet 4.6 or GPT-5.3-Codex?
Claude Sonnet 4.6 leads GPT-5.3-Codex on 2 of the 3 benchmarks they both report (BullshitBench v2, Next.js Evals, Arena Elo (Code)). GPT-5.3-Codex shipped 12 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.
On BullshitBench v2, Claude Sonnet 4.6 leads at 91% vs GPT-5.3-Codex at 24%. On Next.js Evals, GPT-5.3-Codex leads at 83% vs Claude Sonnet 4.6 at 58%. On Arena Elo (Code), Claude Sonnet 4.6 leads at 1521 vs GPT-5.3-Codex at 1406.
Frequently asked questions
Claude Sonnet 4.6 was released by Anthropic on Feb 17 2026.
GPT-5.3-Codex was released by OpenAI on Feb 5 2026.
GPT-5.3-Codex leads on Next.js Evals — Claude Sonnet 4.6 58% vs GPT-5.3-Codex 83%.
Other comparisons
Claude Sonnet 4.6 vs Gemini OmniGPT-5.3-Codex vs Gemini OmniClaude Sonnet 4.6 vs Muse Spark 1.1GPT-5.3-Codex vs Muse Spark 1.1Claude Sonnet 4.6 vs Grok 4.5GPT-5.3-Codex vs Grok 4.5Claude Sonnet 4.6 vs DeepSeek-V4-ProGPT-5.3-Codex vs DeepSeek-V4-ProClaude Sonnet 4.6 vs Mistral Medium 3.5GPT-5.3-Codex vs Mistral Medium 3.5Claude Sonnet 4.6 vs Kimi K2.7 CodeGPT-5.3-Codex vs Kimi K2.7 Code