This skill should be used when the user asks "where is this API endpoint implemented", "find the code for this route", "which file handles this endpoint", "map API findings to code", or needs to correlate OpenAPI spec paths with source code locations. Also use when creating fix plans for code-first API projects (NestJS, Fastify, Express) after running baume-review, or when user mentions "find my NestJS controller", "locate Fastify route handler", "Express route definition".