Claude Opus 4.8

{
  "id": "anthropic/claude-opus-4-8",
  "name": "Claude Opus 4.8",
  "description": "Top Claude Opus tier for the hardest reasoning, coding, and long-horizon agents",
  "family": "claude-opus",
  "last_updated": "2026-05-28",
  "knowledge": "2026-01",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "temperature": false,
  "modalities": {
    "input": [
      "text",
      "image",
      "pdf"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 1000000,
    "output": 128000
  },
  "benchmarks": [
    {
      "name": "SWE-Bench Pro",
      "score": 69.2,
      "source": "https://www.anthropic.com/news/claude-opus-4-8",
      "metric": "resolve rate",
      "date": "2026-05-28"
    },
    {
      "name": "Terminal-Bench",
      "score": 74.6,
      "source": "https://www.anthropic.com/news/claude-opus-4-8",
      "metric": "success rate",
      "harness": "Terminus-2",
      "version": "2.1",
      "date": "2026-05-28"
    },
    {
      "name": "SWE-Bench Verified",
      "score": 88.6,
      "source": "https://benchlm.ai/benchmarks/sweVerified",
      "metric": "resolved"
    },
    {
      "name": "Humanity's Last Exam",
      "score": 49.8,
      "source": "https://www.anthropic.com/news/claude-fable-5-mythos-5",
      "metric": "accuracy",
      "variant": "no tools",
      "date": "2026-06-09"
    },
    {
      "name": "Humanity's Last Exam",
      "score": 57.9,
      "source": "https://www.anthropic.com/news/claude-fable-5-mythos-5",
      "metric": "accuracy",
      "variant": "with tools",
      "date": "2026-06-09"
    },
    {
      "name": "OSWorld-Verified",
      "score": 83.4,
      "source": "https://www.anthropic.com/news/claude-fable-5-mythos-5",
      "metric": "success rate",
      "date": "2026-06-09"
    },
    {
      "name": "FrontierCode",
      "score": 13.4,
      "source": "https://www.anthropic.com/news/claude-fable-5-mythos-5",
      "metric": "pass rate",
      "variant": "high effort",
      "dataset": "Diamond",
      "date": "2026-06-09"
    }
  ],
  "release_date": "2026-05-28",
  "open_weights": false
}