- Extract HTTP_METHODS constant to types.ts (eliminates duplication in 3 files)
- Add DEFAULT_CACHE_MAX_SIZE and DEFAULT_CACHE_TTL_MINUTES constants to cache.ts
- Create schema-utils.ts with getSchemas, findSchema, getSchemaNames, getSchemaCount
- Create spec-guards.ts with isOpenAPIV3, isSwaggerV2, getSpecVersion type guards
- Create tool-response.ts with successResponse, errorResponse helpers
- Update all tool handlers to use response helpers (~50 lines reduced)
- Update parser.ts to use type guards for version detection
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>