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- OpenAPI 3.0.x and 3.1.x are supported. A newer 3.x revision is read
on a best-effort basis (as 3.1) with a warning; Swagger 2.0 is rejected —
convert it first, e.g. with
swagger2openapi.
- Only local
$refs are resolved. A reference into another file or a URL
is not fetched; it degrades to a bare object in the tool’s input schema.
- Request bodies are always sent as JSON. An operation whose
content offers
no application/json (or …+json) media type still gets a body argument,
built from the first media type it does declare.
- OpenAPI 3.1
webhooks are not exposed as tools: a webhook is a callback the
upstream API sends to the server, not an operation the server can call.
- Cookie parameters are ignored.
- An upstream response body is read whole into memory, with no size limit; a
binary body reaches the client base64-encoded in full.
- Templated
servers URLs (https://{region}.example.com) are not expanded;
pass --base-url for those.
- The legacy
sse transport is kept for compatibility but is deprecated by the
MCP specification; prefer http for new remote deployments.
