feat: integrate with MCPO perhaps via a new Transport

[afraazali]

MCPO (https://docs.openwebui.com/openapi-servers/mcp/) exposes your MCP tools over HTTP using OpenAPI. Under the hood I believe it uses FastAPI which generates the OpenAPI spec.

It would be cool to see a new OpenAPI transport, which could parse the OpenAPI spec document and make the proper requests.

Here's a sample OpenAPI spec document from an MCP Server that gets weather alerts:

{
  "openapi": "3.1.0",
  "info": {
    "title": "weather",
    "description": "weather MCP Server",
    "version": "1.8.0"
  },
  "paths": {
    "/get_alerts": {
      "post": {
        "summary": "Get Alerts",
        "description": "Get weather alerts for a US state.\n\n    Args:\n        state: Two-letter US state code (e.g. CA, NY)",
        "operationId": "tool_get_alerts_post",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/get_alerts_form_model"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {
                  "title": "Response Tool Get Alerts Post"
                }
              }
            }
          },
          "422": {
            "description": "Validation Error",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/HTTPValidationError"
                }
              }
            }
          }
        },
        "security": [
          {
            "HTTPBearer": [
              
            ]
          }
        ]
      }
    },
    "/get_forecast": {
      "post": {
        "summary": "Get Forecast",
        "description": "Get weather forecast for a location.\n\n    Args:\n        latitude: Latitude of the location\n        longitude: Longitude of the location",
        "operationId": "tool_get_forecast_post",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/get_forecast_form_model"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {
                  "title": "Response Tool Get Forecast Post"
                }
              }
            }
          },
          "422": {
            "description": "Validation Error",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/HTTPValidationError"
                }
              }
            }
          }
        },
        "security": [
          {
            "HTTPBearer": [
              
            ]
          }
        ]
      }
    }
  },
  "components": {
    "schemas": {
      "HTTPValidationError": {
        "properties": {
          "detail": {
            "items": {
              "$ref": "#/components/schemas/ValidationError"
            },
            "type": "array",
            "title": "Detail"
          }
        },
        "type": "object",
        "title": "HTTPValidationError"
      },
      "ValidationError": {
        "properties": {
          "loc": {
            "items": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "integer"
                }
              ]
            },
            "type": "array",
            "title": "Location"
          },
          "msg": {
            "type": "string",
            "title": "Message"
          },
          "type": {
            "type": "string",
            "title": "Error Type"
          }
        },
        "type": "object",
        "required": [
          "loc",
          "msg",
          "type"
        ],
        "title": "ValidationError"
      },
      "get_alerts_form_model": {
        "properties": {
          "state": {
            "type": "string",
            "title": "State",
            "description": ""
          }
        },
        "type": "object",
        "required": [
          "state"
        ],
        "title": "get_alerts_form_model"
      },
      "get_forecast_form_model": {
        "properties": {
          "latitude": {
            "type": "number",
            "title": "Latitude",
            "description": ""
          },
          "longitude": {
            "type": "number",
            "title": "Longitude",
            "description": ""
          }
        },
        "type": "object",
        "required": [
          "latitude",
          "longitude"
        ],
        "title": "get_forecast_form_model"
      }
    },
    "securitySchemes": {
      "HTTPBearer": {
        "type": "http",
        "scheme": "bearer"
      }
    }
  }
}