Migrate to Claude Sonnet 5: Upgrade Checklist
A migration checklist for teams moving prompts, workflows, and automations from earlier Claude models to Claude Sonnet 5.
TL;DR
Migrating to Claude Sonnet 5 should be treated as an engineering change, not a model-name swap. Build an evaluation set, compare outputs, measure cost and quality, roll out gradually, and keep fallback routing in place.
Step 1: Verify Official Parameters
Before touching production, confirm:
- Model ID
- Pricing
- Rate limits
- Context limits
- Output limits
- Tool support
- Regional availability
- Data retention terms
Do not copy implementation details from blog posts or social media.
Step 2: Build a Regression Set
Create 30 to 100 real examples from your current workflow:
- Normal requests
- High-value requests
- Edge cases
- Known failure cases
- Low-quality user input
- Multi-turn examples
For coding systems, include real diffs, failing tests, logs, and refactor tasks.
Step 3: Define Scoring
Evaluate by observable outcomes:
- Did it complete the task?
- Did it follow the required format?
- Did it reduce human edit time?
- Did it introduce factual errors?
- How many turns did it take?
- What was the token cost?
For enterprise tasks, add policy compliance and auditability.
Step 4: Roll Out Gradually
A practical rollout:
- 5% internal usage
- 25% low-risk workflows
- 50% normal workflows
- 100% default routing after review
Track failure rate, user satisfaction, latency, total cost, and manual correction time at each stage.
Step 5: Keep Fallbacks
Fallback routing should trigger on:
- API errors
- Output validation failures
- Cost anomalies
- User dissatisfaction
- Quality regressions
- Safety or policy flags
Keep the previous model available until Sonnet 5 has proven stable on real workloads.
Bottom Line
Claude Sonnet 5 may be a strong default upgrade, but production systems need evidence. A measured migration gives you the upside of the new model without betting your workflow on a launch-day assumption.