[Feature Request]: Support application/x-www-form-urlencoded Requests in MCP Gateway UI for OAuth2 / Keycloak Integration

[vksinha10]

Hi Team,

We are attempting to integrate an OAuth2 token request via the MCP Gateway UI, specifically with a Keycloak-based authentication service at the endpoint:

/auth/realms//protocol/openid-connect/token

This endpoint expects a POST request with the following characteristics:

Content-Type: application/x-www-form-urlencoded

Body:

grant_type=password&username=systemadmin@system.com&password=

Currently, the MCP Gateway UI only supports input through JSON Schema (via Schema Builder or raw JSON input). This limitation prevents us from sending properly encoded x-www-form-urlencoded requests.

Problem

All attempts result in the body being improperly encoded as JSON.

Keycloak rejects the request with errors such as:

400 Bad Request: {"error":"invalid_request","error_description":"Missing form parameter: grant_type"}

Feature Request

Add support in the MCP Gateway UI for:

Selecting Content-Type: application/x-www-form-urlencoded

Sending properly encoded form parameters (not JSON-wrapped) in the request body