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Claude Opus 5.5

AnthropicProprietaryPending Human Review

Claude Opus 5.5 is the first released Claude 5.5 tier, designed for sustained agentic coding and professional work. Anthropic positions it near Fable 5.1 on most workloads with substantially lower cost than Opus 5, partly through token efficiency. It has always-on adaptive thinking, a million-token context, text and image input, and broad tool access. Effort settings control the latency and computation devoted to a task.

2026-09-22
Unreleased
Undisclosed proprietary architecture
Proprietary

Specifications

Parameters
Unreleased
Architecture
Undisclosed proprietary architecture
License
Proprietary
Context Window
1,000,000 tokens
Max Output
128,000 tokens
Training Data Cutoff
2026-06
Type
multimodal
Modalities
textimage

Benchmark Scores

Advanced Specifications

Model Family
Claude
API Access
Available
Chat Interface
Available
Multilingual Support
Yes
Variants
claude-opus-5-5

Capabilities & Limitations

Capabilities
agentic codingadaptive thinkingvisioncomputer usetool use
Known Limitations
Can make factual or coding errors; tool results and important outputs require verification.Longer reasoning and agent work increase latency and token consumption.
Notable Use Cases
long-running engineeringprofessional analysisdocument workflows
Function Calling Support
Yes
Tool Use Support
Yes

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