claude-opus-4-5-migration
Migrate your code and prompts from Sonnet 4.x and Opus 4.1 to Opus 4.5.
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Migrate your code and prompts from Sonnet 4.x and Opus 4.1 to Opus 4.5.
Installation
npx claude-plugins install @anthropics/claude-code-plugins/claude-opus-4-5-migration
Contents
Folders: skills
Files: README.md
Documentation
Migrate your code and prompts from Sonnet 4.x and Opus 4.1 to Opus 4.5.
Overview
This skill updates your code and prompts to be compatible with Opus 4.5. It automates the migration process, handling model strings, beta headers, and other configuration details. If you run into any issues with Opus 4.5 after migration, you can continue using this skill to adjust your prompts.
Usage
"Migrate my codebase to Opus 4.5"
Learn More
Refer to our prompting guide for best practices on prompting Claude models.
Authors
William Hu (whu@anthropic.com )
Included Skills
This plugin includes 1 skill definition:
claude-opus-4-5-migration
Migrate prompts and code from Claude Sonnet 4.0, Sonnet 4.5, or Opus 4.1 to Opus 4.5. Use when the user wants to update their codebase, prompts, or API calls to use Opus 4.5. Handles model string updates and prompt adjustments for known Opus 4.5 behavioral differences. Does NOT migrate Haiku 4.5.
View skill definition
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
- Search codebase for model strings and API calls
- Update model strings to Opus 4.5 (see platform-specific strings below)
- Remove unsupported beta headers
- Add effort parameter set to
"high"(seereferences/effort.md) - Summarize all changes made
- 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
Remove the context-1m-2025-08-07 beta header if present—it is not yet supported with Opus 4.5. Leave a comment noting this:
# Note: 1M context beta (context-1m-2025-08-07) not yet supported with Opus 4.5
Target Model Strings (Opus 4.5)
| Platform | Opus 4.5 Model String |
|---|---|
| Anthropic API (1P) | claude-opus-4-5-20251101 |
| AWS Bedrock | anthropic.claude-opus-4-5-20251101-v1:0 |
| Google Vertex AI | claude-opus-4-5@20251101 |
| Azure AI Foundry | claude-opus-4-5-20251101 |
Source Model Strings to Replace
| Source Model | Anthropic API (1P) | AWS Bedrock | Google Vertex AI |
|---|---|---|---|
| Sonnet 4.0 | claude-sonnet-4-20250514 | anthropic.claude-sonnet-4-20250514-v1:0 | claude-sonnet-4@20250514 |
| Sonnet 4.5 | `claude-so |
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