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Claude Opus 5.5 (Standard)
The default flagship mode for autonomous repository coding, complex multi-step reasoning, computer use, and enterprise knowledge workflows with always-on adaptive thinking.
CLAUDE OPUS 5.5 · COMING SOON
Frontier reasoning, long-horizon agentic coding, computer use, and 1M context window
Claude Opus 5.5 API: Frontier Agentic Coding, Knowledge Work & Computer Use
Claude Opus 5.5 is Anthropic's flagship intelligence model optimized for long-horizon autonomous coding, complex multi-step knowledge work, and end-to-end computer use. Reaching frontier performance on Terminal-Bench 4.0, FrontierCode, and GDPval, it delivers Claude Fable-level reasoning at ~40% lower overall task cost than Claude Opus 5.
Equipped with a 1-million-token context window, up to 128K synchronous output tokens, and always-on adaptive thinking, Claude Opus 5.5 will soon be accessible on PoYo through unified high-concurrency APIs—providing developers and enterprises with scalable frontier intelligence without waitlists.
Available Claude Opus 5.5 Models and Modes on PoYo
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Claude Opus 5.5 Fast Mode
Research preview mode providing up to 2.5× faster generation speed for real-time interactive development and latency-critical agent tasks.
Key Features of Claude Opus 5.5 API
Frontier benchmarks, always-on adaptive thinking, 1M context, and end-to-end desktop computer use turn ambitious engineering challenges into reliable workflows.
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Claude Opus 5.5 API for Long-Horizon Agentic Coding
Claude Opus 5.5 establishes new frontier performance in terminal-based coding, multi-repository architecture, and autonomous software engineering. Scoring 66.4% on Terminal-Bench 4.0 and 54.4% on FrontierCode, it handles large-scale codebase migrations, complex debugging, and end-to-end refactoring with fewer steps and lower token overhead.
- 66.4% on Terminal-Bench 4.0 and 54.4% on FrontierCode
- Accomplishes 680k-line migrations in under a day
- Autonomous debugging, refactoring, and test verification
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Claude Opus 5.5 API for End-to-End Computer Use & Visual Reasoning
Using the updated computer_toolset_20260801 toolset, Claude Opus 5.5 seamlessly interacts with desktop software, browsers, terminal environments, and complex multi-application workflows. Scoring 81.8% on OSWorld 2.0 and 89.0% on Chartography, it couples visual perception with precise cursor and keyboard actions.
- 81.8% score on OSWorld 2.0 desktop evaluation
- Visual chart, diagram, and dense document comprehension
- Robust multi-application navigation and form workflows
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Claude Opus 5.5 API Always-On Adaptive Thinking & Token Efficiency
Adaptive thinking is natively integrated and continuously active, dynamically allocating cognitive depth according to task complexity. Controlled by the effort parameter, it generates output over 30% faster and uses fewer tokens per task, cutting typical workload execution costs by approximately 40% compared to Opus 5.
- Adaptive thinking always on with configurable effort
- >30% faster output generation speed than Opus 5
- ~40% overall task cost reduction via token efficiency
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Claude Opus 5.5 API 1M Context Window with Enterprise Safeguards
Process entire code repositories, extensive documentation, and complex multi-turn histories with a 1,000,000-token context window and up to 128K synchronous output tokens (300K via Batches API). Built with Anthropic's strongest behavioral safety audit results, it provides 85% higher containment resistance and robust safeguards.
- 1M token context and 128K max synchronous output
- Prompt caching with 512-token threshold and 60% savings
- Anthropic's highest behavioral safety audit score to date
Who Can Benefit from Claude Opus 5.5 API?
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Software Engineers & Autonomous Coding Agents
Automate large codebase migrations, cross-file refactoring, autonomous test generation, and complex terminal debugging with frontier coding benchmarks.
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Enterprise Knowledge Workers & Analysts
Execute end-to-end multi-step analysis, synthesis across thousands of business documents, financial modeling, and structured report drafting in seconds.
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Autonomous Agent & Workflow Architects
Build robust multi-agent systems and long-horizon autonomous workflows with reliable tool selection, append-only conversation patterns, and self-verification.
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Computer Use & Desktop Automation Developers
Automate complex desktop and browser operations, form interactions, data entry, and multi-window workflows with native computer use tools.
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Scientific & Multidisciplinary Researchers
Explore interdisciplinary problem spaces, academic paper synthesis, molecular or mathematical reasoning, and data-intensive research pipelines.
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Financial, Legal & High-Stakes Audit Teams
Perform thorough contract reviews, regulatory compliance verification, code vulnerability audits, and trading-desk workflow automation with superior alignment.
Claude Opus 5.5 vs Claude Opus 5 & Claude Fable 5.1 — Model Comparison
Compare Claude Opus 5.5 with Claude Opus 5 and Claude Fable 5.1 across agentic coding, computer use, reasoning architecture, context limits, and cost efficiency.
| Feature / Metric | Claude Opus 5.5 | Claude Opus 5 | Claude Fable 5.1 |
|---|---|---|---|
| Context window | 1,000,000 tokens | 200,000 / 1,000,000 tokens | 1,000,000 tokens |
| Max output tokens | 128K (sync) / 300K (batch) | 8K / 128K tokens | 128K tokens |
| Terminal coding (Terminal-Bench 4.0) | 66.4% | 52.3% | 55.8% |
| Agentic coding (FrontierCode v1.1) | 54.4% | 48.0% | 50.3% |
| Computer use (OSWorld 2.0) | 81.8% | 74.0% | 80.7% |
| Adaptive thinking | Always-on (effort low to max) | Optional (budget_tokens) | Always-on (adaptive) |
| Official input / output per 1M | $4.00 / $20.00 | $5.00 / $25.00 | $8.00 / $40.00 |
| Cache read price per 1M | $0.20 (-60% vs Opus 5) | $0.50 | $0.80 |
| Typical task cost saving | ~40% lower vs Opus 5 | Baseline | Premium flagship |
Official benchmark data based on Anthropic release system card (September 22, 2026). Typical task savings combine token efficiency with lower per-token pricing.
How to Integrate Claude Opus 5.5 API on PoYo
Step 1: Register & Create API Key
Sign up on PoYo and generate your universal API key in seconds. Instant access with no waiting list.
Create API Key →
Step 2: Top Up Credits
Add credits to your account. Enjoy transparent pay-as-you-go pricing with automatic prompt caching discounts.
Add Credits →
Step 3: Integrate Claude Opus 5.5
Call the Messages API using model ID claude-opus-5-5 via official Anthropic SDKs or PoYo REST endpoints.
View Documentation →
Frequently Asked Questions about Claude Opus 5.5 API
What is Claude Opus 5.5 and what are its key strengths?
Claude Opus 5.5 is Anthropic's flagship large language model released on September 22, 2026. It is optimized for long-running agentic coding, multi-repository software development, complex knowledge work, and computer use, achieving Claude Fable-level reasoning at substantially lower cost.
How does Claude Opus 5.5 compare with Claude Fable 5.1 and Claude Opus 5?
Anthropic reports that Opus 5.5 matches Fable 5.1 on most real-world engineering benchmarks while costing ~60% less per token and ~40% less per task than Opus 5. It outperforms Opus 5 across coding, computer use, and knowledge evaluations.
Can I disable adaptive thinking in Claude Opus 5.5?
No. Adaptive thinking is always on and cannot be disabled. Requests specifying thinking type disabled will return an error. You can control the depth, latency, and cost of reasoning via the effort parameter (low, medium, high, xhigh, max).
What are the main breaking changes when migrating from Opus 5?
Key breaking changes include: (1) thinking cannot be disabled, (2) forced tool use is not supported (use auto or none), (3) thinking blocks are bound to the generating model and conversation history, and (4) computer use requires the updated computer_toolset_20260801 tool version.
How much cheaper is Claude Opus 5.5 in actual production workloads?
Typical production workloads cost ~40% less than Claude Opus 5. This savings is achieved through a 20% reduction in base input and output rates, a 60% reduction in cache read prices ($0.20/MTok), and significant token efficiency improvements per task.
What are the context window and output token limits?
Claude Opus 5.5 features a 1,000,000-token context window. Maximum output is 128,000 tokens for synchronous Messages API requests, and up to 300,000 tokens via the Message Batches API.
How can developers integrate Claude Opus 5.5 through PoYo?
Once available, developers can make standard Anthropic Messages API calls using model ID claude-opus-5-5, pointing their base URL to PoYo with their PoYo API key for instant, high-concurrency access without waitlists.
Why Choose PoYo for Claude Opus 5.5 API Integration
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Instant Access & No Waitlist
Skip provider access waitlists and obtain production-ready API keys immediately with zero onboarding friction.
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Industry-Leading Pricing & 60% Cache Savings
Benefit from transparent pay-as-you-go pricing, 60% prompt caching savings, and 50% discounts on batch workloads.
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Enterprise Reliability & 99.9% Uptime
Rely on redundant multi-cloud infrastructure, strict SLA guarantees, and enterprise-grade rate limits for high-volume agents.
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Unified API & Multi-Model Ecosystem
Switch seamlessly between Anthropic Claude, OpenAI, and open-source models using a single standardized API and unified billing.