MiscSubjects

Anthropic: Claude Opus 5.5

Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.

AnthropicClaude Opus 5.5
anthropic/claude-opus-5.5
2026-09-22text+image+file->textreasoning: max / xhigh / high / medium / low
Intelligence index
59.1
Artificial Analysis
Design Arena
1348 Elo · #1
codetovideo · 73.2% wins
Input
$4
per 1M tokens
Output
$20
per 1M tokens
Cached input
$0.20
per 1M tokens
Context
1M
tokens it reads
Max output
128K
tokens it writes
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...
inspect — the catalog entry
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      {
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      {
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      },
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        "arena": "models",
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      },
      {
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      },
      {
        "arena": "models",
        "category": "uicomponent",
        "elo": 1375,
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      },
      {
        "arena": "models",
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        "elo": 1325,
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      "coding_index": null,
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      "max",
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      "high",
      "medium",
      "low"
    ],
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  }
}
References (1)
  1. Stored model catalog — Nov 5, 2026
Via
OpenRouter
Id
openrouter/anthropic/claude-opus-5.5
Model id
anthropic/claude-opus-5.5
Name
Anthropic: Claude Opus 5.5
Description
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
Family
anthropic
Canonical slug
anthropic/claude-opus-5.5-20260921
Price in
4
Price out
20
Price cache read
0.19999999999999998
Price cache write
5
Price cache write 1h
8
Price web search
10000
Price overrides
[]
Context
1000000
Max completion tokens
128000
Modality
text+image+file->text
Input modalities
["text","image","file"]
Output modalities
["text"]
Tokenizer
Claude
Knowledge cutoff
null
Created
1790094732
Moderated
true
Params
["include_reasoning","max_completion_tokens","max_tokens","reasoning","reasoning_effort","response_format","stop","structured_outputs","tool_choice","tools","verbosity"]
Default parameters
{}
Tools
true
Reasoning
true
Reasoning efforts
["max","xhigh","high","medium","low"]
Reasoning default effort
high
Reasoning mandatory
true
Reasoning default enabled
null
Vision
true
Expiration date
null
Page dataOpen JSON
page.json
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