GPT-5.3-Codex

{
  "id": "openai/gpt-5.3-codex",
  "name": "GPT-5.3 Codex",
  "description": "Coding-optimized GPT model for repository edits, reviews, and agentic software work",
  "family": "gpt-codex",
  "last_updated": "2026-02-05",
  "knowledge": "2025-08-31",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "structured_output": true,
  "temperature": true,
  "modalities": {
    "input": [
      "text",
      "image",
      "pdf"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 400000,
    "input": 272000,
    "output": 128000
  },
  "benchmarks": [
    {
      "name": "SWE-Atlas Codebase QnA",
      "score": 32.6,
      "source": "https://labs.scale.com/leaderboard/sweatlas-qna",
      "metric": "score",
      "harness": "Codex"
    },
    {
      "name": "SWE-Atlas Refactoring",
      "score": 42.38,
      "source": "https://labs.scale.com/leaderboard/sweatlas-refactoring",
      "metric": "score",
      "harness": "Codex"
    },
    {
      "name": "SWE-Atlas Test Writing",
      "score": 38.98,
      "source": "https://labs.scale.com/leaderboard/sweatlas-tw",
      "metric": "score",
      "harness": "Codex"
    }
  ],
  "release_date": "2026-02-05",
  "open_weights": false
}