mcp servers don't expose tool schemas in openapi format, makes integration with existing systems painful

every mcp server i've tested exposes tool schemas in its own json format, not openapi/swagger. this means you can't just point existing api gateways or validation layers at them without writing custom parsers. tested on 6 different mcp servers (filesystem, github, slack, postgres, redis, and one custom) and none of them provide openapi specs. you have to manually convert the mcp schema format to openapi if you want to integrate with standard tooling. is there a reason mcp doesn't just use openapi for tool schemas or am i missing something obvious