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claude-opus-5-5

AnthropicChatReasoningVision
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claude-opus-5-5

A deep reasoning model for cross-codebase engineering and complex analysis

Claude Opus 5.5 is a high-capability model in the Anthropic Claude 5.5 family, focused on cross-file programming, complex knowledge work, and image-text analysis. It combines adaptive thinking with clearer expression, making it suitable for tasks that require continuously organizing context, checking assumptions, and delivering reviewable results. Use the Messages API on this platform to organize work around text, images, and multi-turn feedback.

AnthropicModel brand
ChatModel type
Reasoning, visual understandingTask capabilities
STANDARD APIs · QUICK SETUP

Keep your SDK. Connect in minutes.

Point the Base URL to api.acedata.cloud, configure your platform API key and the model ID below, and use your compatible SDK or client.

API hostapi.acedata.cloud
modelclaude-opus-5-5
Anthropic Python SDK
import os
from anthropic import Anthropic

client = Anthropic(
    auth_token=os.environ["ACEDATACLOUD_API_KEY"],
    base_url="https://api.acedata.cloud",
)
response = client.messages.create(
    model="claude-opus-5-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.content)

Choose an available protocol for this model. OpenAI SDK uses a Base URL ending in /v1; Anthropic SDK uses the root URL. See each guide for protocol-specific parameters, tools and response formats.

Specifications and interface features

Clarify capacity, input/output, and invocation methods before selecting a model.

Context capacity
Platform Messages endpoint: 1 million Token
Maximum output
Platform Messages endpoint: 128K Token; thinking and main text share the budget
Input methods
Mixed text and image input; supports multi-turn messages
Output methods
Text content blocks; tool workflows use tool_use and tool_result
Reasoning method
Adaptive thinking is always enabled; thinking cannot be turned off
Invocation endpoint
/v1/messages; model is claude-opus-5-5
Input estimation
/v1/messages/count_tokens supports this model

Adaptive thinking is a model capability; the capacity figures and interface paths correspond to this platform's Messages invocation endpoint.

Core capabilities

Learn what claude-opus-5-5 can bring to your work.

Handle cross-file changes as a complete engineering task

Opus 5.5 excels at codebase migrations, audits, and multi-file changes, rather than merely completing a function. Providing the relevant code, interface constraints, and regression requirements together enables it to trace dependencies, explain the reasons for changes, and propose validation steps, helping reviewers determine whether the changes preserve existing behavior.

Move from source materials to verifiable analytical conclusions

It is well suited to financial analysis, business judgment, and research across multiple materials, organizing facts, assumptions, and conclusions around task objectives. After providing raw data, definitions, and citation requirements, you can ask it to deliver an evidence list and items requiring confirmation, making analysis results easier to check item by item instead of producing only a fluent summary.

Image and text understanding with clearer communication

Its visual capabilities allow it to answer questions using charts or interface screenshots; its writing emphasizes leading with important information and following communication rules. You can place images and task instructions in the same message and ask it to organize responses by observations, explanations, and recommendations, reducing the burden on readers of finding key conclusions in lengthy text.

Use cases

Start with specific tasks to find where the model can make an impact.

Migration planning and code review

Provide the modules to be migrated, call relationships, code differences, and test results, and let the model organize the scope of impact, potential behavior changes, and repair recommendations. Deliverables can include a file-level review checklist, migration steps, and a test plan; when connected to programming tools, the execution environment can then run tests and return failure information.

Financial and operational analysis memos

Provide financial data, metric definitions, business context, and decision questions, and require a distinction between known facts and scenario assumptions. The model can help generate operational analysis memos, comparison tables, and management summaries; listing calculation bases and key figures separately makes it easier to manually verify definitions and determine whether conclusions are supported.

Chart interpretation and communication materials

Enter trend charts, flowcharts, or product screenshots together with specific questions, and ask it to explain the relationships in the image, visible changes, and data that needs to be added. You can then turn the analysis into explanatory copy for engineers or managers, retaining the same material foundation while adjusting terminology, length, and the order in which information is presented.

How to choose this model

Choose based on task complexity, input materials, and expected results.

Migrating from Opus 5: compare complete deliverables first

Compared with Opus 5, the key improvements in Opus 5.5 are complex engineering, knowledge work, and communication clarity. It is recommended to run comparative tests using existing code review or analysis tasks, comparing whether results pass acceptance, how much rework is needed, and the amount of manual review required. During migration, especially remove assumptions about disabling thinking, and allocate a shared output budget for reasoning and the main text.

Choose between it and Fable 5.1 based on actual hard problems

Anthropic positions Opus 5.5 as a model that can reach Fable 5.1-level performance for most work, but this does not mean all difficult problems perform the same. For cross-codebase engineering, comprehensive reports, and text-and-image explanations, try Opus 5.5 first; existing Fable 5.1 workflows should use the same materials and acceptance criteria for comparison, retaining the more stable choice for critical tasks.

Start with a specific task

Based on the characteristics of claude-opus-5-5, first validate small tasks whose results can be checked.

01

Cross-codebase migration review

You can ask directly: compare the protocols, data models, and migration plans in two services, and list the differences that would change production behavior. Output the scope of impact, the step-by-step migration sequence, and verifiable rollback conditions.

02

Prepare inputs that support decisions

Provide protocol versions, relevant code, and real test results; cross-repository dependencies and key assumptions should have evidence that can be checked.

03

Then integrate it into your workflow

Use the full model ID claude-opus-5-5, first confirm the public request format and available parameters on the API page, then connect your application. Preserve result parsing, exception handling, and related evidence, and use the same set of real samples to evaluate whether it is suitable for continued use.

Usage boundaries

Before formal use, understand the output quality and range of capabilities.

  • Opus 5.5 cannot disable thinking, so it is not suitable for legacy workflows that depend on a completely no-reasoning mode. max_tokens limits the combined total of thinking and body text, rather than only the length of the visible answer; when the budget is small, the body text may be incomplete, and applications should check the stop reason and properly arrange continuations.
  • Programming and tool-use capabilities do not mean that a single request will automatically access repositories, run code, or operate interfaces. Tool functions must still be executed by the application or programming environment, and the results then returned; production changes should establish authorization boundaries, testing thresholds, and human approval to avoid directly accepting unverified patches.
  • Stronger material analysis and prompt-injection defenses do not mean that answers are necessarily correct. Financial conclusions should be reviewed for methodology and calculations, and chart assessments should be checked against the original data; sensitive tasks such as cybersecurity and biology may still be subject to safety restrictions, and general programming capability cannot be treated as a universal guarantee for all specialized tasks.

Frequently Asked Questions

Answers to common questions when using claude-opus-5-5.

Can Opus 5.5 directly reuse OpenAI chat calls?

This model uses /v1/messages; you cannot simply replace the model in an OpenAI chat request. System prompts use a separate system field, and responses are read from the content block array; clients should also handle stop_reason rather than parsing results according to the choices structure.

Can thinking be disabled to generate only short answers?

Thinking cannot be disabled, but you can explicitly request a short final answer. The length of the visible text and whether the model performs reasoning are different matters; the output budget needs to accommodate both, so do not set max_tokens too tightly just because you request a one-sentence answer.

Is a 1 million-token context suitable for putting the entire repository into it?

A larger context is suitable for retaining related code, specifications, and historical feedback, but that does not mean all materials are worth submitting. Prioritize modules and dependencies relevant to the task, and use count_tokens to estimate the input size before sending; clear acceptance criteria are usually more helpful than piling in unrelated files.

How should multi-turn tool tasks with Opus 5.5 be handled?

Read responses by content block type. When tool_use is encountered, have the application execute the corresponding function, then return the result with tool_result. Multi-turn messages should retain the complete reasoning blocks and signatures returned by the model; do not rewrite signatures yourself. Tool outputs and authorization scope should also be reviewed separately.

Can Opus 5.5's vision capabilities be used to generate images?

The vision capability here is used to understand images and produce textual analysis, not as an image generation endpoint. It is suitable for submitting charts, flowcharts, or screenshots and asking about trends, relationships, and interface changes; when precise numbers are involved, it is best to also provide a data table so visual observations and numerical evidence can be cross-checked.