Skip to content
claude-opus-4-5-migration logo

Opus 4.5 Migration Guide

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.

SKILL.md

Full skill instructions

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

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)

PlatformOpus 4.5 Model String
Anthropic API (1P)claude-opus-4-5-20251101
AWS Bedrockanthropic.claude-opus-4-5-20251101-v1:0
Google Vertex AIclaude-opus-4-5@20251101
Azure AI Foundryclaude-opus-4-5-20251101

Source Model Strings to Replace

Source ModelAnthropic API (1P)AWS BedrockGoogle Vertex AI
Sonnet 4.0claude-sonnet-4-20250514anthropic.claude-sonnet-4-20250514-v1:0claude-sonnet-4@20250514
Sonnet 4.5claude-sonnet-4-5-20250929anthropic.claude-sonnet-4-5-20250929-v1:0claude-sonnet-4-5@20250929
Opus 4.1claude-opus-4-1-20250422anthropic.claude-opus-4-1-20250422-v1:0claude-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.

Integration guidelines: When adding snippets, don't just append them to prompts. Integrate them thoughtfully:

  • Use XML tags (e.g., <code_guidelines>, <tool_usage>) to organize additions
  • Match the style and structure of the existing prompt
  • Place snippets in logical locations (e.g., coding guidelines near other coding instructions)
  • If the prompt already uses XML tags, add new content within appropriate existing tags or create consistent new ones

1. Tool Overtriggering

Opus 4.5 is more responsive to system prompts. Aggressive language that prevented undertriggering on previous models may now cause overtriggering.

Apply if: User reports tools being called too frequently or unnecessarily.

Find and soften:

  • CRITICAL: → remove or soften
  • You MUST... → You should...
  • ALWAYS do X → Do X
  • NEVER skip... → Don't skip...
  • REQUIRED → remove or soften

Only apply to tool-triggering instructions. Leave other uses of emphasis alone.

2. Over-Engineering Prevention

Opus 4.5 tends to create extra files, add unnecessary abstractions, or build unrequested flexibility.

Apply if: User reports unwanted files, excessive abstraction, or unrequested features. Add the snippet from references/​prompt-snippets.md.

3. Code Exploration

Opus 4.5 can be overly conservative about exploring code, proposing solutions without reading files.

Apply if: User reports the model proposing fixes without inspecting relevant code. Add the snippet from references/​prompt-snippets.md.

4. Frontend Design

Apply if: User requests improved frontend design quality or reports generic-looking outputs.

Add the frontend aesthetics snippet from references/​prompt-snippets.md.

5. Thinking Sensitivity

When extended thinking is not enabled (the default), Opus 4.5 is particularly sensitive to the word "think" and its variants. Extended thinking is enabled only if the API request contains a thinking parameter.

Apply if: User reports issues related to "thinking" while extended thinking is not enabled (no thinking parameter in request).

Replace "think" with alternatives like "consider," "believe," or "evaluate."

Reference

See references/​prompt-snippets.md for the full text of each snippet to add.

See references/​effort.md for configuring the effort parameter (only if user requests it).

More skills from HelixDevelopment

fireflies-local-dev-loop logo
HelixDevelopment/HelixAgent

fireflies-local-dev-loop

Configure Fireflies.ai local development with hot reload and testing. Use when setting up a development environment, configuring test workflows, or establishing a fast iteration cycle with Fireflies.ai. Trigger with phrases like "fireflies dev setup", "fireflies local development", "fireflies dev...

0 0
View
clerk-security-basics logo
HelixDevelopment/HelixAgent

clerk-security-basics

Implement security best practices with Clerk authentication. Use when securing your application, reviewing auth implementation, or hardening Clerk configuration. Trigger with phrases like "clerk security", "secure clerk", "clerk best practices", "clerk hardening".

0 0
View
openrouter-team-setup logo
HelixDevelopment/HelixAgent

openrouter-team-setup

Configure OpenRouter for team and organizational use. Use when setting up multi-user access or department billing. Trigger with phrases like 'openrouter team', 'openrouter organization', 'multi-user openrouter', 'openrouter rbac'.

0 0
View
coderabbit-security-basics logo
HelixDevelopment/HelixAgent

coderabbit-security-basics

Apply CodeRabbit security best practices for secrets and access control. Use when securing API keys, implementing least privilege access, or auditing CodeRabbit security configuration. Trigger with phrases like "coderabbit security", "coderabbit secrets", "secure coderabbit", "coderabbit API key ...

0 0
View
detecting-infrastructure-drift logo
HelixDevelopment/HelixAgent

detecting-infrastructure-drift

Execute use when detecting infrastructure drift from desired state. Trigger with phrases like "check for drift", "infrastructure drift detection", "compare actual vs desired state", or "detect configuration changes". Identifies discrepancies between current infrastructure and IaC definitions usin...

0 0
View
cursor-reference-architecture logo
HelixDevelopment/HelixAgent

cursor-reference-architecture

Execute reference architecture patterns for Cursor IDE projects. Triggers on "cursor architecture", "cursor project structure", "cursor best practices", "cursor team setup". Use when working with cursor reference architecture functionality. Trigger with phrases like "cursor reference architecture...

0 0
View
vastai-security-basics logo
HelixDevelopment/HelixAgent

vastai-security-basics

Apply Vast.ai security best practices for secrets and access control. Use when securing API keys, implementing least privilege access, or auditing Vast.ai security configuration. Trigger with phrases like "vastai security", "vastai secrets", "secure vastai", "vastai API key security".

0 0
View
instantly-incident-runbook logo
HelixDevelopment/HelixAgent

instantly-incident-runbook

Execute Instantly incident response procedures with triage, mitigation, and postmortem. Use when responding to Instantly-related outages, investigating errors, or running post-incident reviews for Instantly integration failures. Trigger with phrases like "instantly incident", "instantly outage", ...

0 0
View
configuring-load-balancers logo
HelixDevelopment/HelixAgent

configuring-load-balancers

Configure use when configuring load balancers including ALB, NLB, Nginx, and HAProxy. Trigger with phrases like "configure load balancer", "create ALB", "setup nginx load balancing", or "haproxy configuration". Generates production-ready configurations with health checks, SSL termination, sticky ...

0 0
View
building-recommendation-systems logo
HelixDevelopment/HelixAgent

building-recommendation-systems

Execute this skill empowers AI assistant to construct recommendation systems using collaborative filtering, content-based filtering, or hybrid approaches. it analyzes user preferences, item features, and interaction data to generate personalized recommendations... Use when appropriate context det...

0 0
View
perplexity-multi-env-setup logo
HelixDevelopment/HelixAgent

perplexity-multi-env-setup

Configure Perplexity across development, staging, and production environments. Use when setting up multi-environment deployments, configuring per-environment secrets, or implementing environment-specific Perplexity configurations. Trigger with phrases like "perplexity environments", "perplexity s...

0 0
View
juicebox-sdk-patterns logo
HelixDevelopment/HelixAgent

juicebox-sdk-patterns

Apply production-ready Juicebox SDK patterns. Use when implementing robust error handling, retry logic, or enterprise-grade Juicebox integrations. Trigger with phrases like "juicebox best practices", "juicebox patterns", "production juicebox", "juicebox SDK architecture".

0 0
View

Popular AI tools

Kaiber logo
Video

Kaiber

Generate, edit, and beat-sync AI video with leading models in one workspace.

Paid
View
Vimcal logo
Productivity

Vimcal

The world's fastest calendar for remote work

Free
View

Transform Your Design with AI Designer by ImgCreator.ai

Freemium
View
Akool AI logo
Content & writing

Akool AI

Revolutionizing Video Production with AI-Powered Creativity

Paid
View

Extend an image past the frame and let AI fill the new aspect ratio.

Freemium
View
StarByFace logo
Security

StarByFace

Discover your celebrity doppelgänger with StarByFace!

Free
View
C

ChainClarity explains 700+ crypto whitepapers in plain English, with layered summaries, comparisons, research tools, alerts, and a $4.99 Pro plan.

Freemium
View
Opus Clip logo
Coding & apps

Opus Clip

Opus.ai: Revolutionize Your Web Experience

Free
View