How does this skill handle prompt behavioral differences?

If you report issues like over-engineering or tool overtriggering, the skill provides specific XML-tagged snippets and terminology adjustments to refine Opus 4.5's behavior.

Does this skill migrate Haiku models?

No, this skill is specifically designed to migrate from Sonnet 4.0, Sonnet 4.5, and Opus 4.1 to Opus 4.5 only.

Which cloud platforms are supported for model string updates?

The skill supports model string updates for the direct Anthropic API (1P), AWS Bedrock, Google Vertex AI, and Azure AI Foundry.

Why does the skill remove the 1M context beta header?

The context-1m-2025-08-07 beta header is currently not supported with Opus 4.5; the skill removes it to prevent API request failures.

What is the 'effort' parameter mentioned in the migration?

Opus 4.5 supports an effort parameter that, when set to 'high', tells the model to use more computation for complex reasoning and better task performance.

Claude Opus 4.5 Migration Guide

Name: Claude Opus 4.5 Migration Guide
Author: akiojin

byakiojin

•

API Development

Upgrades existing Claude Sonnet and Opus integrations to the Opus 4.5 model with optimized parameters and behavioral adjustments.

About

This skill facilitates a seamless transition from legacy Claude models (Sonnet 4.0/4.5 and Opus 4.1) to the high-performance Opus 4.5. It automates the replacement of platform-specific model strings for Anthropic API, AWS Bedrock, Google Vertex AI, and Azure AI Foundry while ensuring deprecated beta headers are safely removed. Beyond simple string replacement, the skill provides intelligent guidance for adjusting system prompts to mitigate Opus 4.5-specific behaviors—such as tool overtriggering or over-engineering—and configures advanced reasoning parameters to ensure your codebase leverages the full capabilities of the latest flagship model.

Key Features

Targeted prompt adjustments to fix tool overtriggering and over-engineering
1 GitHub stars
Configuration of the high-effort reasoning parameter for complex tasks
Automated model string migration for Anthropic, AWS, Google, and Azure platforms
Smart removal of unsupported beta headers with inline documentation
Frontend design optimization snippets for improved UI output quality

Use Cases

Upgrading a production API integration from Sonnet 4.5 to the latest Opus 4.5 model
Standardizing LLM model strings across multi-cloud environments like Bedrock and Vertex AI
Refactoring system prompts to prevent unwanted abstractions and file creation

About

Key Features

Targeted prompt adjustments to fix tool overtriggering and over-engineering
1 GitHub stars
Configuration of the high-effort reasoning parameter for complex tasks
Automated model string migration for Anthropic, AWS, Google, and Azure platforms
Smart removal of unsupported beta headers with inline documentation
Frontend design optimization snippets for improved UI output quality

Use Cases

Upgrading a production API integration from Sonnet 4.5 to the latest Opus 4.5 model
Standardizing LLM model strings across multi-cloud environments like Bedrock and Vertex AI
Refactoring system prompts to prevent unwanted abstractions and file creation