Claude Opus 5.5Latest
For long-running agentic coding and knowledge work
- Context window
- 1Mtokens
- Max output
- 128Ktokens
- Input pricing
- $4/ MTok
- Output pricing
- $20/ MTok
Overview
Claude Opus 5.5 is built for long-running agentic coding and knowledge work, priced at $4 / $20 USD per million input / output tokens. Four breaking changes affect code already running on Claude Opus 5: thinking can't be disabled, forced tool use returns an error, thinking blocks are tied to the model and the conversation, and, on the Claude API and Google Cloud, the earlier computer_20251124 computer use tool is not accepted. The first three also apply on Claude Fable 5.1. A further change alters the response shape without failing any request: text between tool calls comes back in thinking blocks whose text is empty at the default display setting. An application that streams that text to its users as progress updates goes quiet between tool calls until it sets a display value that returns the text.
How it compares
| Model | Context | Max output | Price / MTok | Latency | Thinking | Default effort | Knowledge cutoff |
|---|---|---|---|---|---|---|---|
| Claude Fable 5.1 | 1M | 128K | $10 / $50 | Slower | Adaptive (always on) | high | Jun 2026 |
| Claude Opus 5.5This model | 1M | 128K | $4 / $20 | Moderate | Adaptive (always on) | medium | Jun 2026 |
| Claude Sonnet 5 | 1M | 128K | $2 / $10 | Fast | Adaptive | high | Jan 2026 |
| Claude Haiku 4.5 | 200K | 64K | $1 / $5 | Fastest | Extended | — | Feb 2025 |
Specifications
Model IDs
- Claude API
Pricing
- Input
- $4 / MTok
- Output
- $20 / MTok
- 5m cache write
- $5 / MTok
- 1h cache write
- $8 / MTok
- Cache read
- $0.20 / MTok
- Batch API
- 50% discount on input and output
- Full price list
- Pricing
Capabilities
- Context window
- 1M tokens
- Max output
- 128K tokens
- Max output (Batch API, beta)
- 300K tokens
- Thinking
- Adaptive (always on)
- Default effort
medium- Comparative latency
- Moderate
- Input → output
- Text and images → text
- Reliable knowledge cutoff
- Jun 2026
- Training data cutoff
- Jun 2026
Availability
- Status
- Active (latest)
- Released
- September 22, 2026
- Retirement
- Not sooner than September 22, 2027
- Platforms
- Claude APIAmazon BedrockGoogle CloudMicrosoft FoundryClaude Platform on AWS
Good to know
- Adaptive thinking is always on and can't be turned off. Control thinking depth with the effort parameter.
- On the Message Batches API, Claude Opus 5.5 supports up to 300k output tokens with the
output-300k-2026-03-24beta header. - The minimum cacheable prompt length is 512 tokens. See Prompt caching.
- Query limits and capabilities programmatically with the Models API.
Resources
Behavioral differences and prompting patterns specific to Claude Opus 5.5.
The control for thinking depth, latency, and cost. Choose a level per workload.
How adaptive thinking works and how thinking blocks are preserved.
Lower-latency Claude Opus 5.5 on the Claude API (research preview), priced separately.
Reference
The system prompt Claude Opus 5.5 uses on claude.ai and the Claude apps.
Safety evaluations and deployment decisions for Claude Opus 5.5.
Full price list, including batch discounts and prompt caching rates.
How model IDs, aliases, and pinned snapshots work.
Lifecycle status and retirement commitments for every Claude model.
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