Borrowing it
Nothing to install: this file belongs to akiojin/playfab-mcp-server. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/akiojin/playfab-mcp-server/main/.claude/skills/claude-opus-4-5-migration/SKILL.mdgit clone --depth 1 https://github.com/akiojin/playfab-mcp-serverWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/akiojin/playfab-mcp-server/claude-opus-4-5-migration)<a href="https://agentmods.dev/skills/akiojin/playfab-mcp-server/claude-opus-4-5-migration"><img src="https://agentmods.dev/badge/skills/akiojin/playfab-mcp-server/claude-opus-4-5-migration/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/akiojin/playfab-mcp-server/claude-opus-4-5-migration"><img src="https://agentmods.dev/badge/skills/akiojin/playfab-mcp-server/claude-opus-4-5-migration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00100 | $0.01281 |
| Opus 5 | $0.00050 | $0.00641 |
| Sonnet 5 | $0.00020 | $0.00256 |
| Haiku 4.5 | $0.00010 | $0.00128 |
Grade A, and why
claude-opus-4-5-migration scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
94% identical to opus-4-5-migration — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 106 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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-sonnet-4-5-20250929 |
anthropic.claude-sonnet-4-5-20250929-v1:0 |
claude-sonnet-4-5@20250929 |
| Opus 4.1 | claude-opus-4-1-20250422 |
anthropic.claude-opus-4-1-20250422-v1:0 |
claude-opus-4-1@20250422 |
Do NOT migrate: Any Haiku models (e.g., claude-haiku-4-5-20251001).
Prompt Adjustments
Opus 4.5 has known behavioral differences from previous models. Only apply these fixes if the user explicitly requests them or reports a specific issue. By default, just update model strings.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 11d ago First seen · 106 lines · 100 tokens per session scan A ec3f9c16195a
claude-opus-4-5-migration is a skill published in the GitHub repository akiojin/playfab-mcp-server (3 stars, last pushed yesterday), licensed MIT. It adds 100 tokens to every session and 1,281 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to opus-4-5-migration, differing in 8 lines, and is treated as a copy.
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