Claude Opus
Anthropic’s Claude Opus 5.5 (claude-opus-5-5, 2026-09-22) for hard agentic work. Anthropic says it matches Fable 5.1 on most work; Fable remains a separate higher-priced SKU.
Anthropic’s Claude Opus 5.5 (API id claude-opus-5-5, released 2026-09-22) for complex agentic coding, enterprise work, long-context analysis, and careful instruction following. Anthropic says it matches Fable 5.1 on most work at a lower price. Fable 5.1 remains a separate higher list-price SKU. Sonnet 5.5 (claude-sonnet-5-5, 2026-09-28) is the current Sonnet at the same $2/$10 list price as Sonnet 5. Haiku 5.5 (claude-haiku-5-5, 2026-10-07) is the current Haiku.
Why Claude Opus matters
Opus 5.5 is what teams pin when instruction following, long-context synthesis, and careful agentic coding matter more than raw price. List price is $4/$20 per 1M tokens. Fable 5.1 stays available at $10/$50; escalate to it only when an eval shows a gap.
Vision · Tool calling · Thinking · MCP · Coding
Last reviewed: 27 September 2026
When to choose Claude Opus
Decision guidance for architects—not a feature list.
Best for
- Long-document analysis
- Agentic coding with verification
- High-stakes writing and policy
- Research assistants with tools
Avoid if
- You need the cheapest Claude tier for high-volume chat
- Open weights or audio-first multimodal are requirements
Strengths
DataAIHub qualitative scores from 1 to 5, for architects. Not official benchmark results or a public ranking.
- Instruction following★★★★★
- Agentic coding★★★★★
- Long context★★★★★
- Cost efficiency★★☆☆☆
- Open weights★☆☆☆☆
Ecosystem
Built by
- Anthropic
Opus 5.5 is Anthropic’s current high-capability generally available tier. Fable 5.1 remains a separate higher-priced SKU.
Competes with
- GPT-5
Primary closed-model rival for coding agents and enterprise assistants.
Works with
Recommended for
- AI Agents
Preferred when agent reliability and verification loops matter most.
Often paired with
- Claude Sonnet
Teams often route hard tasks to Opus and everyday production traffic to Sonnet.
How Claude Opus evolved
Key moments in chronological order.
- API
Opus 5.5 one-hour cache lifetime
API keys and cloud providers can set a one-hour prompt-cache lifetime (subscribers already had it). Forked subagents start from the parent cache. Changing effort mid-session does not reset the cache on Opus 5.5 or Fable 5.1. List prices are unchanged.
- Model
First Claude 5.5-family model (claude-opus-5-5). Priced at $4 input / $20 output per 1M tokens (cache read $0.20, cache write $5; fast mode $8/$40). Anthropic says it matches Fable 5.1 on most work and costs less to run than Opus 5. Thinking cannot be disabled, and forced tool use returns an error. Sonnet 5.5 and Haiku 5.5 are not released yet.
- API
Computer use is generally available as computer_toolset_20260801; browser_toolset_20260801 adds viewport/accessibility-tree control. Supported on Opus 5 (and peer Claude tiers).
- Model
Opus 5 ships as Anthropic’s everyday high-capability tier for agentic coding and 1M context at the same API rates as Opus 4.8.
- Product
1M-token context class
Document-heavy analysis and long agent threads become practical.
- Platform
MCP support expands
Model Context Protocol tooling broadens Claude’s agent integration surface.
- Product
Computer-use style workflows
UI and tool-driven agent patterns push Claude into operational automation.
- Model
Claude 3 Opus launches
Establishes Opus as Anthropic’s peak-capability brand in the Claude family.
Overview
Capabilities
- Vision: Yes
- Audio input: No
- Tool calling: Yes
- Thinking: Yes
- MCP: Yes
- Coding: Yes
- Structured output: Yes
Technical specifications
- Provider
- Anthropic
- License
- Proprietary
- Context window
- 1M
- Parameters
- Undisclosed
- Architecture
- Transformer (proprietary)
- Release
- 2026-09
- Modalities
- Text, Image
- Vision
- Yes
- Audio input
- No
- Tool calling
- Yes
- Thinking
- Yes
- MCP
- Yes
- Open weights
- No
- API
- Yes
- Pricing (input)
- ~$4 per 1M tokens (claude-opus-5-5)
- Pricing (output)
- ~$20 per 1M tokens
Supported modalities
Text · Image
Context window
1M (1,000,000 tokens)
Pricing
Cache read $0.20 / cache write $5 per 1M tokens. Fast mode $8 input / $40 output. Opus 5 list rates were $5/$25 with cache reads at $0.50. Verify platform.claude.com.
Availability
Claude API id claude-opus-5-5 (2026-09-22); also Amazon Bedrock, Google Cloud, Microsoft Foundry, and Claude Platform on AWS. Thinking cannot be disabled. Forced tool use returns an error. On the Claude API and Google Cloud, the earlier computer_20251124 computer-use tool is not accepted. Computer use GA (computer_toolset_20260801) and browser use (browser_toolset_20260801) shipped 2026-08-19. Messages API on-demand compaction is a 2026-09-14 beta (compact-2026-09-04). System card knowledge cutoff is June 2026. As of 2026-09-24, API keys and cloud providers can set a one-hour prompt-cache lifetime (subscribers already had it); forked subagents reuse the parent cache; changing effort mid-session does not reset the cache (also on Fable 5.1).
Use cases
- Long-document analysis and synthesis
- High-stakes writing and policy drafting
- Agentic coding and computer/browser-use workflows
- Research assistants with tool use
Strengths
- Current Opus API id (claude-opus-5-5) at $4/$20 per 1M tokens
- Anthropic reports Fable 5.1-level results on most work at lower cost than Opus 5
- 1M-token context for document-heavy work
Limitations
- Closed weights
- Fable 5.1 remains a separate SKU at $10/$50 per 1M tokens
- Thinking cannot be disabled; forced tool use errors
- Audio modality limited vs some peers
Related guides
Related benchmarks
Related research
- Introducing Claude Opus 5.5
Original Paper
- Claude Opus 5.5 model overview
Evaluation
- Opus 5.5 cache lifetime for long coding sessions
Original Paper
Related GitHub
Related tools
Related rankings
Related comparisons
Companies
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