---
name: principle-migrate-callers-then-delete-legacy-apis
description: "Apply when introducing a new internal API while old callers still exist. Migrate callers and delete the old API in the same wave instead of preserving compatibility layers."
disable-model-invocation: true
---
## OpenAI runtime contract

Read [the adapter contract](../../references/runtime-contract.md) before this workflow. It maps provider selection, agent calls, loops, persistent state, history, verification, and authorization. That contract supersedes Cursor-specific execution syntax and unverified model fallbacks below; the engineering steps remain required. Use native tools in the current host by default. Cloud uses its available OpenAI models. No remote laptop connection, server URL or MCP setup is permitted. Optional local CLI adapters require explicit environment-local selection. Do not claim cross-provider diversity for OpenAI-only review.


# Migrate Callers Then Delete Legacy APIs

When we decide a new API is the right design, migrate callers and remove the old API in the same refactor wave instead of preserving compatibility layers.

**Rule:**
- Do not keep legacy API paths only because internal callers still exist
- Inventory callers, migrate them, and delete the old API immediately
- Treat temporary adapters as exceptional and time-boxed, not default architecture
- Update tests to assert the new contract, and delete tests that only protect pre-refactor implementation details

**When this applies:**
- No external users depend on backward compatibility
- The project can absorb coordinated breaking changes
- The new API is part of a simplification or refactor initiative

Keeping both old and new APIs creates dual-path complexity, slows cleanup, and makes the codebase feel append-only.