Model Context Protocol (MCP) tool arguments are sent to the location their OpenAPI parameter declares

Model Context Protocol (MCP) tool arguments are sent to the location their OpenAPI parameter declares

This change applies to Apigee X in all supported regions.

An MCP tool argument whose OpenAPI parameter declares in: header is now sent to your backend as a request header, and one that declares in: cookie is sent in the Cookie header. Previously both were appended to the query string. in: query and in: path parameters are unchanged, and every parameter still appears in the tool's inputSchema, so MCP clients supply arguments exactly as before. If a backend reads one of these values from the query string, declare the parameter in: query or read it from its declared location.

On a tool call that supplies at least one cookie argument, the Cookie header is replaced with only the declared cookie parameters, omitting any others. Any cookie your backend relies on must be declared as an in: cookie parameter.

An MCP proxy that was already deployed continues to use the previous query-string behavior until its configuration is next regenerated. To adopt the new routing on an existing MCP proxy, deploy a new revision of it.

For the full mapping, see Tool argument placement on the backend request.