claude-opus-4-5-migration

To migrate Claude API calls to Opus 4.5, update your model strings to 'claude-opus-4-5-20251101' across Anthropic API, AWS Bedrock, Google Vertex AI, and Azure AI Foundry, then adjust prompts to address behavioral differences like tool overtriggering.

When upgrading to Opus 4.5, prompt adjustments are needed to mitigate behavioral differences such as tool overtriggering and over-engineering, ensuring the new model maintains or improves output quality without unexpected actions.

No, you cannot migrate Haiku models to Opus 4.5 using this approach. The migration process specifically supports upgrading from older Claude models like Sonnet 4.0, Sonnet 4.5, and Opus 4.1, explicitly excluding Haiku models.

Yes, Opus 4.5 migration supports AWS Bedrock and Google Vertex AI. It automatically handles model string updates across multiple platforms including Anthropic API, AWS Bedrock, Google Vertex AI, and Azure AI Foundry.

Opus 4.5 may overtrigger tools after a model upgrade due to behavioral differences from previous versions. Adjusting system prompts with specific guidance snippets helps control this overtriggering and prevents over-engineering responses.

The correct model string for Opus 4.5 in the Anthropic API is 'claude-opus-4-5-20251101'. Updating your codebase to use this specific identifier ensures compatibility and access to the latest model features.