claude-opus-4-5-migration

Installation
Summary

Migrate Claude model strings and prompts from Sonnet 4.0, Sonnet 4.5, or Opus 4.1 to Opus 4.5.

  • Updates model strings across Anthropic API, AWS Bedrock, Google Vertex AI, and Azure AI Foundry platforms
  • Removes unsupported beta headers (e.g., context-1m-2025-08-07) and adds effort parameter set to "high"
  • Provides optional prompt adjustments for known Opus 4.5 behavioral differences: tool overtriggering, over-engineering, code exploration conservatism, frontend design, and thinking sensitivity
  • Does not migrate Haiku models; only handles Sonnet 4.0, Sonnet 4.5, and Opus 4.1 sources
SKILL.md

Opus 4.5 Migration Guide

One-shot migration from Sonnet 4.0, Sonnet 4.5, or Opus 4.1 to Opus 4.5.

Migration Workflow

  1. Search codebase for model strings and API calls
  2. Update model strings to Opus 4.5 (see platform-specific strings below)
  3. Remove unsupported beta headers
  4. Add effort parameter set to "high" (see references/effort.md)
  5. Summarize all changes made
  6. Tell the user: "If you encounter any issues with Opus 4.5, let me know and I can help adjust your prompts."

Model String Updates

Identify which platform the codebase uses, then replace model strings accordingly.

Unsupported Beta Headers

Related skills

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Jan 20, 2026