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Anthropic · Frontier

Claude Opus 5.5

Added Sep 22, 2026

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Use in the app

Claude Opus 5.5 is Anthropic's flagship model for agentic coding, computer use, complex knowledge work, and long-running tasks, with improved efficiency and more natural communication.

  • Reasoning
  • Tools
  • Vision
  • Structured output
  • PDF input
Input
Text, Images
Output
Text
Reasoning effort
low · medium · high · xhigh · max
Discovery tier
Frontier

Pricing

USD per 1M tokens
Input
$4.00
Output
$20.00
Cache read
$0.20
Cache write
$5.00
$8.00 for a 1-hour cache

Reference prices as published by the model provider. API example

Specifications

Context window
1M
Max output
128K
Average output (7 days)
2K tokens
Longer than 92% of 473 models

Side by side

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TryGemini 4 ArgonMuse WonderKimi K3.1 ProAll 3

Public evaluations

Benchmarks

Independent evaluation results, with how each score ranks among the models in the Noumen catalog.

Intelligence Index

53.6

Tested at high reasoning effort

Better than 98% of 326 scored models

3.8Catalog models by score55.1

Agentic work

  • AutomationBench-AA

    63.2%

    Workflow automation, penalized for guardrail violations

    Better than 90% of 173 scored models

  • AutomationBench-AA tasks completed

    33.8%

    Workflows finished end to end without a guardrail violation

    Better than 93% of 173 scored models

  • AA-Briefcasev1.1

    1,683 Elo

    Agentic knowledge work, rated head to head

    Better than 99% of 166 scored models

  • GDPval-AAv2.1

    1,704 Elo

    Economically valuable occupational tasks, rated head to head

    Better than 94% of 187 scored models

Document reasoning

  • GDP.pdf

    28.8%

    Professional reasoning over PDF documents, all-pass rate

    Better than 94% of 171 scored models

  • AA-LCRv1.1

    82.7%

    Reasoning across long documents

    Better than 88% of 309 scored models

  • MLCR-AA

    15.0%

    Long-context reasoning over medical records

    Better than 64% of 121 scored models

Reasoning and knowledge

  • Humanity’s Last Exam

    55.6%

    Expert-level questions across academic fields

    Better than 98% of 323 scored models

Coding

  • Terminal-Benchv4.0

    56.6%

    Practical software engineering in a terminal

    Better than 97% of 171 scored models

  • SciCode

    60.4%

    Scientific computing in Python

    Better than 94% of 174 scored models

Legacy evaluations

  • AA-LCR (unversioned)

    82.7%

    Long-context reasoning, earlier grading

    Better than 88% of 309 scored models

Scores from Artificial Analysis, updated Oct 26, 2026. Claude Opus 5.5 was tested at high reasoning effort; compare scores measured at the same effort.Artificial Analysis

Live routing data

Performance and reliability

Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.

Throughput
226.9 tok/s
Faster than 88% of 259 models
Time to first token
4.9 s
Quicker than 31% of 259 models
Prompt cache hits
51.1%
About $2.06 per 1M input tokens with caching
Request success (24h)
99.8%
Reliable

Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.

Hourly request success · last 72 hoursLowest hour 79.5%
  • Healthy (98% or more)
  • Degraded (90–98%)
  • Down (under 90%)
  • No requests

Developers

Use it through the API

Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.

Read the quickstart
curl https://www.noumen.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer $NOUMEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-opus-5.5",
    "reasoning_effort": "medium",
    "messages": [{ "role": "user", "content": "Explain this stack trace." }]
  }'
import os
from openai import OpenAI

client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
    model="anthropic/claude-opus-5.5",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

Anthropic

Other Anthropic models, starting with the same family.