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claude-opus-4-5-20251101

AnthropicChatReasoningVision
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claude-opus-4-5-20251101

Deep reasoning model for complex code and long-horizon tasks

Claude Opus 4.5 is Anthropic's model for complex programming, in-depth analysis, and agent tasks, and claude-opus-4-5-20251101 is its date-pinned version. It excels at understanding ambiguous requirements, weighing multiple approaches, and organizing solution paths using text and images. It is suited to work requiring deep judgment, step-by-step progress, and repeated verification, rather than simply generating a short answer.

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-4-5-20251101
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-4-5-20251101",
    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, inputs and outputs, and invocation methods before choosing a model.

Version identifier
Claude Opus 4.5 date-pinned version: claude-opus-4-5-20251101
Input methods
Text, images, and mixed text-image messages
Output methods
Text responses, code, analysis reports, and tool invocation requests
Native reasoning control
Adjustable effort for thinking in the Claude API
Invocation endpoints
/v1/chat/completions、/aichat2/conversations
Conversations and files
AI Chat v2 supports conversation continuation, streaming events, and file_url file-reading workflows

Native effort is a control capability of the Claude API; this platform's message format, conversation persistence, and tool execution are determined by the selected interface and authorization configuration.

Core Capabilities

Learn what claude-opus-4-5-20251101 can bring to your work.

From Complex Failures to Verifiable Fixes

The programming focus of Opus 4.5 is not just code completion, but understanding cross-module dependencies and modification trade-offs. After providing error logs, relevant code, and expected behavior, you can ask it to first organize failure hypotheses, then propose fixes, test cases, and regression checks. It is suitable for refactoring, migration, and issues that are difficult to pinpoint directly.

Turn Vague Goals into Execution Paths

When facing tasks with incomplete conditions or conflicting goals, it is well suited to first identify key constraints and then compare feasible options. Agent applications can use its planning and tool-use capabilities to connect querying, analysis, and result organization; performing external actions still requires tool connections, permission configuration, and result feedback.

Understand Business Materials with Images

The model has visual understanding capabilities and can analyze interface screenshots, charts, and document images together with text-based questions. Compared with reading text alone, combined image and text input is better suited for discussing layouts, abnormal states, and chart relationships; providing clear images and necessary context helps generate explanations and recommendations tailored to specific materials.

Use Cases

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

Code Migration and Architecture Review

Provide existing modules, the target technology stack, compatibility requirements, and testing constraints, and have the model produce a migration sequence, a list of interface changes, and key code drafts. More complex projects can be discussed in stages: confirm the design first, then make changes item by item, and finally check for omissions using test results, avoiding one-shot rewrites that are difficult to validate.

Research Materials and Decision Memos

Provide research questions, source text, or file links, and ask the model to compare viewpoints, extract assumptions, and organize items to be verified. AI Chat v2 can work with file-reading or search tools to process materials and deliver summaries, option comparisons, and action recommendations; current facts should be based on retrieval results rather than relying solely on the model's knowledge.

Chart Interpretation and Interface Diagnosis

Submit business charts, product screenshots, and problem descriptions together, for example to explain metric anomalies, inspect interaction flows, or discuss page redesigns. The model can produce observations, possible causes, and modification priorities; when precise values are involved, also provide the raw data so that visual judgments can be separated from data verification.

How to choose this model

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

Prioritize Opus 4.5 for complex tasks

Compared with Sonnet 4.5, Opus 4.5 is more worthwhile for difficult code, complex trade-offs, and tasks requiring sustained reasoning. Official software engineering evaluations show that its medium effort can already achieve Sonnet 4.5's best results, but this does not mean every business will receive the same benefit. For routine extraction and short Q&A, evaluate lighter-weight options first.

Fixed versions and interfaces each have their uses

When an existing project has established a test set around Opus 4.5, you can continue using the date-fixed version to manage version dependencies, but a fixed ID does not mean responses will be completely identical. If you manage message history yourself and integrate with an existing SDK, choose Chat Completions; if you need to save conversations, read files, and observe the tool process, choose AI Chat v2.

Get started

From a small-scale task to production integration.

01

Prepare tasks and materials

Define the goal, required inputs, and output requirements, using real business examples as a starting point.

02

Try it in the API testing area

Open the trial page, confirm the parameters supported by this entry point, then submit a small-scale task to review the results.

03

Integrate according to the API documentation

Keep the complete model ID, use the request format specified in the documentation, and confirm billing rules on the Pricing page.

Usage limits

Before formal use, understand output quality and capability boundaries.

  • Programming and computer-use capabilities do not mean code can be run or a desktop operated simply by submitting a single instruction. Regular conversations can generate plans and code, while actual execution depends on the environment and tools provided by the application; before modifying repositories, sending messages, or writing to business systems, set permissions and acceptance steps.
  • Image understanding should not replace precise data extraction. Small text, blurry screenshots, or missing legends may affect judgment; financial analysis and metric calculations should include the original tables, and the model's explanations, calculation results, and business assumptions should be verified separately.
  • Long-running tasks still require managing materials and intermediate results. Clearly stating key constraints, current conclusions, and next-step goals is easier to control than continuously piling up history; date-fixed versions also do not automatically inherit features added later to subsequent models or the Claude application.

Frequently Asked Questions

Answers to common questions about using claude-opus-4-5-20251101.

Is 20251101 the release date of Opus 4.5?

No. 20251101 is part of the invocation ID for the date-pinned version. The official release date of Claude Opus 4.5 is November 24, 2025. Using the full ID when invoking it helps clarify version dependencies, but does not guarantee exactly the same answer every time.

What kinds of programming problems is Opus 4.5 suitable for?

It is better suited for cross-module issues, code refactoring, migration planning, and complex reviews. Provide the relevant code, error messages, expected behavior, and constraints that cannot be changed, then have it first propose a diagnosis and test plan before generating a draft of the changes; the code still needs to be verified in the actual environment.

Can I submit images or PDFs to Opus 4.5?

Images can be submitted together with text through image_url. Files such as PDFs can be handled by the file-reading workflow through file_url in AI Chat v2; multimodal messages in Chat Completions cannot be used directly as a file upload entry point. File links need to be accessible, and pay attention to the reading results.

Are effort and reasoning_effort the same parameter?

They should not be treated directly as the same parameter. effort controls reasoning investment in the native Claude API; compatible interfaces use their own parameter formats and should not be copied mechanically. When in-depth analysis is needed, you can also explicitly request comparison of options, explanation of assumptions, and validation steps in the task.

How can I have Opus 4.5 continue work from the previous turn?

When using AI Chat v2, save the returned id and include the same id in subsequent requests to continue the conversation; stateful is enabled by default. When using Chat Completions, the client organizes the messages history. For long tasks, it is recommended to keep phase summaries and clearly state which conclusions have been confirmed and which items remain to be addressed.

Model information · Updated: 2026-10-01. See the API and pricing sections for invocation parameters and billing rules.