Claude Opus 5.5
NewAlways-on adaptive reasoning for long-running coding and knowledge work.
Released Sep 22, 2026
₹2,123.00
per 10 lakh output tokens
Input: ₹424.60 per 10 lakh tokens
Billed at provider rates converted at ₹96.5 per US dollar, with 0% markup.
Pricing
Benchmarks
Scores are percentages unless marked as a rating. All benchmarks are measured independently.
89.6%
GPQA Diamond
GPQA Diamond - graduate-level science Q&A
61.4%
HLE
Humanity's Last Exam
66.9%
SciCode
SciCode - scientific code generation
84.7%
Long Context
Long Context Reasoning - reasoning over long inputs
About Claude Opus 5.5
Anthropic's model for long-running agentic coding and knowledge work. It uses always-on adaptive thinking, with medium as the direct API's default effort. The model accepts text, images and documents within a one-million-token context and supports up to 128,000 output tokens.
Anthropic presents Opus 5.5 as a model for sustained software engineering and knowledge work. The lab reports performance approaching Claude Fable 5.1 while reducing the cost of completing tasks compared with Opus 5. These are provider evaluations, whose results depend on the task and reasoning effort.
The release emphasizes follow-through: investigating a problem, checking evidence and continuing through longer assignments. Anthropic describes improvements in coding, research and communication, including clearer explanations. That combination suits work where an answer needs both investigation and a useful written result.
The announcement also describes limits and safeguards. Anthropic describes additional safeguards for higher-risk biology and cybersecurity requests. The published examples do not establish reliability for every application. Users should check consequential conclusions and validate generated code within their own projects.
What Anthropic announced at launch
- Longer assignments
- Designed for sustained coding and knowledge work that requires several steps and verification.
- Task efficiency
- Anthropic reports lower task costs than Opus 5, with results varying by reasoning effort.
- Clearer communication
- The launch emphasizes explanations that make research and technical work easier to use.
Indian languages
Claude Opus 5.5 answers in 13 Indian languages. Choose a language from the menu beside the message box to receive replies in it.
Frequently Asked Questions
Frequently asked questions about Claude Opus 5.5.
When was Claude Opus 5.5 released?
Anthropic released Claude Opus 5.5 on Sep 22, 2026.
Who built Claude Opus 5.5?
Claude Opus 5.5 is developed by Anthropic. 99Models AI connects directly to it at the provider's published rate.
How intelligent is Claude Opus 5.5?
It is ranked 1 of 56 chat models on intelligence, ordered by independent benchmark scores. View its complete scores in the Benchmarks table above.
How much does Claude Opus 5.5 cost?
Usage costs ₹424.60 per million input tokens and ₹2,123.00 per million output tokens, with 0% markup. There is no subscription; you pay only for what you use.
What is Claude Opus 5.5 pricing in US dollars?
The provider charges $4.40 per million input tokens and $22.00 per million output tokens. Rupee rates are converted at ₹96.5 per US dollar.
How long a conversation can Claude Opus 5.5 hold?
Its context window is 10 lakh tokens. That is the total volume of text and attached files it can process in a single request.
How does Claude Opus 5.5 rank for value?
It ranks 7 out of 56 models for value. This ranking weighs benchmark intelligence against the actual token cost.
Does Claude Opus 5.5 support reasoning?
Always on. Where reasoning is supported, you can adjust the thinking effort level directly in the message composer.
Which Indian languages does Claude Opus 5.5 support?
It answers in 13 Indian languages. Select your preferred language from the menu beside the message box to receive replies in it.
More models from Anthropic
Catalog updated Sep 23, 2026