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.