Software development and code review
Engineering teams that need a model to inspect a larger codebase, plan changes, use tools, implement a fix, review a pull request, and verify the result.
Independent tool overview
Claude Opus 5.5: features, pricing, and best uses
Claude Opus 5.5 is Anthropic's flagship model for coding, research, writing, document work, and complex agentic tasks across Claude products and the API.
Visit the official Claude Opus 5.5 site ↗
- Best for
- Coding, research, writing, documents, and complex agents
- API model
- claude-opus-5-5
- Context window
- 1 million tokens
- API price
- $4 input / $20 output per 1M tokens
- Default API effort
- Medium
Overview
What Claude Opus 5.5 is
Anthropic released Claude Opus 5.5 on September 22, 2026 as a text-and-image input model for complex professional work. It can analyze documents, code, charts, screenshots, and other supplied context, then return text or use supported tools inside an application workflow.
Anthropic recommends Opus 5.5 as the starting point for most demanding work. Its API model ID is claude-opus-5-5, its context window is one million tokens, and its default API effort is Medium. Teams can raise effort for harder tasks, but should compare the complete result, latency, and token use rather than assuming a higher setting is always better.
The model replaces Opus 5 as the more economical default in the Opus line: Anthropic lists lower standard token rates and reports faster output. The Rundown has not run a controlled head-to-head benchmark for this profile, so performance claims below are attributed to Anthropic and should be checked on your own representative tasks.
Use cases
Who Claude Opus 5.5 is best for
The strongest fit depends on the job you need the product to complete, not the size of its feature list.
Research and document analysis
Analysts working across long reports, policies, source documents, charts, or screenshots who need a structured answer grounded in the supplied material.
Writing from approved source material
Teams drafting briefs, reports, campaigns, or executive communication where the model must follow detailed constraints and preserve supplied facts.
Tool-using agents
Developers building multi-step workflows in which the model plans, calls tools, checks intermediate results, and continues toward a defined outcome.
Capabilities
Core Claude Opus 5.5 features
One-million-token context window
Accepts up to one million tokens of context through the API, giving applications room for large codebases, document sets, or long-running task state when the workflow needs it.
Text and image input
Can analyze text, documents, charts, screenshots, and other images while producing text output for downstream review or automation.
Adjustable effort
Supports effort controls that trade additional reasoning for latency and token use. Anthropic lists Medium as the default API effort for Opus 5.5.
Coding and code-review workflows
Designed for repository-scale implementation, debugging, review, and agentic coding tasks that require multiple steps and tool calls.
Document and spreadsheet work
Anthropic highlights improvements in professional document and spreadsheet workflows, including tasks that combine structured instructions with supplied files.
Tool use and agentic execution
Can participate in applications that provide tools, permissions, and task state, allowing the model to plan and act beyond a single chat response.
Faster, lower-priced Opus generation
Anthropic reports output generation more than 30% faster than Opus 5 and lists standard API rates 20% below Opus 5 for both input and output tokens.
Process
How the Claude Opus 5.5 workflow works
Step 1
Choose the Claude surface
Use Claude for interactive work, Claude Code for repository tasks, or the Claude API and supported cloud platforms for an application workflow.
Step 2
Provide the goal, sources, and constraints
Define the finished output, attach the material the model should use, and state any facts, formats, permissions, or actions that must not be invented.
Step 3
Start with the recommended effort
Begin at the default Medium API effort, then raise effort only when a concrete failure or harder reasoning requirement justifies the extra latency and token use.
Step 4
Let the model use approved tools
For agentic tasks, expose only the tools and data the workflow needs, keep consequential actions bounded, and preserve logs or artifacts for review.
Step 5
Verify the result on a known task
Check facts, calculations, code changes, citations, and tool actions against the source material before relying on the output or migrating an established workflow.
Cost
Claude Opus 5.5 pricing and free plan
Anthropic bills Claude Opus 5.5 API usage by tokens. Access in Claude apps depends on the user's plan and organization settings, and those chat-plan limits are separate from API billing.
Claude products
Plan-dependent access
Use Opus 5.5 in supported Claude experiences when the model is available to the account or organization.
- Chat-plan prices and usage limits are separate from API rates
- Available models can depend on the account and organization settings
- Check the model menu and current plan terms before a large task
Claude API
$4 input · $20 output / 1M tokens
Usage-based access for developers building Opus 5.5 into products, coding systems, and automated workflows.
- Model identifier: claude-opus-5-5
- One-million-token context window
- Effort, tools, prompt caching, and other API features can affect total cost
Pricing checked . Check current pricing at the source ↗
Assessment
Claude Opus 5.5 strengths and limitations
Where it stands out
- Anthropic recommends it as the starting model for most complex work across coding, research, writing, and professional documents.
- The one-million-token context window supports large source sets and longer-running application state when a task genuinely needs that context.
- Standard API rates are lower than Opus 5 and substantially lower than Fable 5.1, making task-level testing easier to justify.
- Text-and-image input, adjustable effort, and tool use make it suitable for both interactive work and agentic application workflows.
What to consider
- Opus 5.5 produces text output; applications that need native image, audio, or video generation require another model or tool.
- A one-million-token limit does not make every long prompt useful. Irrelevant context can add cost and make a task harder to evaluate.
- Higher effort and multi-step tool use can increase latency and token consumption, so unit pricing alone does not predict the cost of a completed task.
- Claude app availability and usage limits depend on the account, plan, and organization settings rather than the API price table.
- Anthropic's performance claims are not an independent Rundown benchmark; teams should test accuracy, speed, and edit time on their own representative work.
Compare
Claude Opus 5.5 alternatives
The right alternative depends on the specific output, workflow, controls and budget your project requires.
Consumer
Claude Fable 5.1
Choose Claude Fable 5.1 when Opus at higher effort still misses an important condition and the harder task justifies Fable's higher token rates.
Explore Claude Fable 5.1 →Consumer
Claude Sonnet 5
Choose Claude Sonnet 5 when a mid-sized, cost-conscious Claude model is a better fit for higher-volume coding or agent workflows.
Explore Claude Sonnet 5 →Consumer
GPT-6 Astra
Choose GPT-6 Astra when the application or team is centered on OpenAI's model ecosystem and a cross-provider comparison matters more than staying in Claude.
Explore GPT-6 Astra →Questions
Claude Opus 5.5 FAQs
What is Claude Opus 5.5?
Claude Opus 5.5 is Anthropic's flagship model for coding, research, writing, document work, and complex agentic tasks. It accepts text and image input and produces text output.
How much does the Claude Opus 5.5 API cost?
As of September 22, 2026, Anthropic lists standard API pricing at $4 per million input tokens and $20 per million output tokens. Chat-plan billing and usage limits are separate.
What is the Claude Opus 5.5 context window?
Anthropic lists a one-million-token API context window. Actual task cost and quality still depend on how much relevant material you send and how the workflow uses it.
What is the Claude Opus 5.5 API model ID?
The published API model identifier is claude-opus-5-5.
How is Opus 5.5 different from Opus 5?
Anthropic lists Opus 5.5 at $4 input and $20 output per million tokens, compared with $5 and $25 for Opus 5. Anthropic also reports more than 30% faster output generation and sets Medium rather than High as the default API effort.
When should I use Fable 5.1 instead of Opus 5.5?
Start with Opus 5.5 for most work. Anthropic recommends trying Fable when Opus at higher effort still misses an important requirement or fails on a particularly demanding reasoning task.
Is this a hands-on Claude Opus 5.5 review?
No. This is an independent editorial overview based on Anthropic's official announcement and documentation. The Rundown has not completed a controlled hands-on model benchmark for this profile.
Bottom line
Our Claude Opus 5.5 verdict
Claude Opus 5.5 is the strongest default starting point in Anthropic's current lineup for complex coding, research, writing, and tool-using work. Its lower Opus pricing, one-million-token context window, and Medium default effort make it easier to test before reaching for Fable 5.1. Teams should still compare real task accuracy, edit time, latency, and full token use before migrating an established workflow.
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