OpenAPI definitions are verbose and exhaustive. In MCPs you can remove a lot of extra material, saving tokens. For example in [1], whole `responses` schema can

OpenAPI definitions are verbose and exhaustive. In MCPs you can remove a lot of extra material, saving tokens. For example in [1], whole `responses` schema can be eliminated. The error texts can instead be surfaced when they appear. You also don't need duplicate json/xml/url-encoded input formats. Secondly, whole lot of complexities are eliminated, arbitrary data can't be sent and received. Finally, the tool output are prompts to the model too, so you can leverage the output for better accuracy, which you can't do with general purpose apis. [1] https://github.com/swagger-api/swagger-petstore/blob/master/src/main/resources/openapi.yaml https://github.com/swagger-api/swagger-petstore/blob/master/...