Prompt Patterns for Reliable AI Refactors
Prompt structures that reduce risk when using AI tools for large codebase refactors.
February 17, 2026 · 8 min read
Why refactors break with AI
The model optimizes local elegance. Refactors fail when hidden contracts and operational assumptions are omitted.
Prompt pattern: Constraints first
Start prompts with hard boundaries:
- do not change public APIs
- preserve error semantics
- keep migration backward-compatible
Prompt pattern: Diff budget
Constrain scope to a small set of files and require checkpoints after each phase.
Prompt pattern: Verification contract
Ask the assistant to produce:
- list of assumptions
- risk areas
- required tests
Human review focus
Verify behavior and compatibility, not stylistic improvements. Refactor wins come from safer architecture, not prettier diffs.