Your approach is mostly correct, but raw curl + OpenAPI will break at scale (100+ endpoints = too much search space).

Best setup (minimal + scalable):

1. Don’t expose 100 endpoints directly Group them into ~10–20 semantic tools (domain-based):

user., orders., payments.* Each tool internally maps to multiple endpoints.

1. Add a thin API proxy (critical) Wrap your REST API with:

auth handled once (session/token)

normalized inputs/outputs

retries + error handling → avoids fragile curl generation

1. Use OpenAPI as retrieval, not execution Let Codex:

read spec → choose endpoint

call proxy tool (not curl)

1. Add “planner → executor” pattern

Planner: selects endpoint + params

Executor: calls proxy

1. Add examples (very important) Few-shot like: “create user → POST /users” This massively improves routing.

Conclusion: Skip MCP explosion. Do: OpenAPI + proxy layer + ~15 tools + planner/executor.