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claude-opus-4-1-20250805

AnthropicChatReasoningVision
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claude-opus-4-1-20250805

A reasoning model for complex code fixes and detail tracking

Claude Opus 4.1 is Anthropic's model for complex programming, research analysis, and agent tasks, and claude-opus-4-1-20250805 is its date-fixed version. Building on Opus 4, it strengthens real-world code tasks and reasoning, making it especially suitable for work that requires cross-file understanding, constraint tracking, and precise fixes. It can also combine image understanding for visual and textual analysis.

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 host
api.acedata.cloud
model
claude-opus-4-1-20250805
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OpenAI Python SDK
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["ACEDATACLOUD_API_KEY"],
    base_url="https://api.acedata.cloud/v1",
)
response = client.chat.completions.create(
    model="claude-opus-4-1-20250805",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.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 and output, and invocation methods before choosing a model.

Version
Claude Opus 4.1, date-fixed version of 2025-08-05
Reasoning method
Native hybrid reasoning model with extended thinking capabilities
Multimodal input and output
Text and image input; text responses
Programming benchmark
Official SWE-bench Verified: 74.5%, without extended thinking
Chat endpoint
Chat Completions or Messages API

Opus 4.1's native capabilities and benchmark results indicate its task focus. The content formats of Chat Completions and Messages are handled independently, while message history and tool execution are maintained by the application.

Core capabilities

Learn what claude-opus-4-1-20250805 can bring to your work.

Cross-file understanding, focused on necessary changes

Opus 4.1's programming improvements go beyond code generation, with greater focus on multi-file refactoring and precise fixes in real projects. After providing relevant modules, errors, and behaviors that must be preserved, you can have it analyze dependencies, identify where changes are needed, and explain the impact, making it suitable for debugging and maintenance work aimed at minimal changes.

Track details in research and analysis

When faced with multiple materials, differing criteria, and complex constraints, Opus 4.1's upgrades focus on in-depth research, data analysis, and detail tracking. It can organize claims, compare conditions, and structure conclusions around the materials provided. Asking responses to distinguish direct evidence, inferences, and items requiring verification makes deliverables easier to review.

Advance complex tasks with text and images

Opus 4.1 can analyze issues by combining interface screenshots, data charts, and task descriptions, helping connect visible anomalies with code or business conditions. Specifying observation areas, evaluation criteria, and expected results, then asking it to distinguish direct evidence from inference, helps apply visual information to engineering investigations.

Applicable Scenarios

Start with specific tasks to find where the model can be effective.

Maintaining Bug Fixes in Large Projects

Provide error stacks, the source files involved, reproduction steps, and interfaces that must not be changed; require the cause to be identified first, followed by patch suggestions and a regression test checklist. It is suitable for maintenance tasks that require cross-module verification and controlled modification scope; delivered code should still enter the testing and review process before being merged.

Organizing Research Materials and Difference Reports

Submit specification versions, research texts, or analysis tables together with specific questions, allowing the model to track details, compare criteria, and organize differences. The report can separately list materials supporting conclusions, conflicting information, and unresolved issues, giving subsequent reviews a clear verification path.

Chart and Interface Issue Analysis

Provide dashboard screenshots, images of interface anomalies, and business context together, asking the model to describe visible information, propose explanations, and list verification steps. It can help turn visual observations into an actionable troubleshooting checklist; when precise values are involved, it is best to also provide the raw data and avoid calculations based solely on screenshots.

How to Choose This Model

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

Trade-offs When Upgrading from Opus 4

If existing tasks use Opus 4 and the main challenges are code debugging, multi-file refactoring, or complex reasoning, Opus 4.1 is a clear upgrade option, and Anthropic also recommends upgrading from Opus 4. During migration, use the same task set to compare modification scope, constraint adherence, and test results rather than looking only at answer length or wording.

Choose Fixed Versions and Endpoints Separately

Applications that already use the OpenAI messages structure can use Chat Completions; if Claude-native content blocks, thinking, or tool_use/tool_result workflows are needed, check Messages API support for this model. Handle the two request, response, and parameter formats separately, and retain the full model ID.

Start with a specific task

Based on the characteristics of claude-opus-4-1-20250805, first validate small tasks whose results can be checked.

01

Trace the root cause of multi-file defects

You can ask directly: Trace the call path from the entry point to data writing, explain how the error propagates, and identify the locations most likely to change behavior. Output minimal patch recommendations and the affected tests.

02

Prepare input that supports sound judgment

Provide the relevant files and logs; verify cross-file changes against actual behavior, and do not treat review suggestions as patches that have already been run.

03

Then integrate it into your workflow

Use the full model ID claude-opus-4-1-20250805, first confirm the public request format and available parameters on the API page, then connect your application. Preserve result parsing, exception handling, and relevant evidence, and evaluate whether it is suitable for continued use with the same set of real samples.

Usage boundaries

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

  • Programming benchmark scores do not equal the success rate of fixes in a project. The model needs relevant code, the runtime environment, and reproduction conditions; without dependencies or test results, it may misjudge the cause. Ask it to explain every change, and validate patches through unit tests, integration tests, and human review.
  • Reasoning capability does not mean that extended thinking is enabled in the same way at every endpoint, nor does it mean that the complete reasoning process must be returned. When designing applications, validate based on the final answer, evidence, and verification steps; do not rely on hidden reasoning content as business data.
  • Visual understanding is for analyzing images, not generating them; tool collaboration also does not mean that the model automatically receives repository write or code execution permissions. File and tool tasks require accessible materials and appropriate authorization, and actions such as publishing, modifying, or sending should retain clear permission boundaries.

Frequently Asked Questions

Answers to common questions about using claude-opus-4-1-20250805.

What version is claude-opus-4-1-20250805?

It is the date-pinned invocation ID for Claude Opus 4.1, corresponding to the version released on August 5, 2025. It is suitable for projects that need a specific version for testing and integration, and should not be confused with Opus 4, later Opus versions, or invocation names with the thinking suffix.

Compared with Opus 4, where are the main improvements?

The upgrade focuses on agentic tasks, real-world coding, and reasoning. The release particularly emphasizes multi-file code refactoring, as well as detail tracking in research and data analysis. If a task requires precise fixes and fewer unrelated changes, you can prioritize evaluating Opus 4.1 with existing code tasks.

Can this version analyze images or PDFs?

Prepare the document text, tabular data, or clear page screenshots relevant to the question, and specify whether you need a summary, comparison, or extraction of particular information. Submit content in formats supported by the selected public interface; a PDF address cannot be used as image_url. Require results to retain original-text locations, field evidence, and unconfirmed items, and verify key numbers against the source materials.

How do I make calls and continue multi-turn conversations?

Include user and assistant messages relevant to the current task in the messages for Messages or Chat Completions, handling the specific format according to the selected public interface. Keep the latest code, interim conclusions, and important constraints; when necessary, re-summarize long histories to avoid relying on outdated information.

Can Opus 4.1 automatically modify and test code?

The model can analyze code, propose patches, and participate in tool-driven programming workflows, but ordinary text requests do not give it access to a runtime environment on their own. Automatic modification and testing require configured available tools and permissions, along with execution results; it is recommended to retain change review, test acceptance, and failure rollback mechanisms.