MCP Server Config JSON Schema

mcp-server-config.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://json.schemastore.org/mcp-config-0.1.0.json",
  "title": "MCP Servers Configuration",
  "description": "Configuration schema for MCP (Model Context Protocol) servers",
  "type": "object",
  "required": ["servers"],
  "additionalProperties": false,
  "properties": {
    "inputs": {
      "type": "array",
      "description": "Array of input configurations",
      "items": {
        "$ref": "#/definitions/input"
      }
    },
    "servers": {
      "type": "object",
      "description": "Map of server configurations",
      "minProperties": 1,
      "patternProperties": {
        "^[a-zA-Z][a-zA-Z0-9_-]*$": {
          "$ref": "#/definitions/server"
        }
      },
      "additionalProperties": false
    }
  },
  "definitions": {
    "promptStringInput": {
      "type": "object",
      "description": "Configuration for string input prompts",
      "required": ["type", "id", "password"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "type": "string",
          "const": "promptString"
        },
        "id": {
          "type": "string",
          "pattern": "^[a-zA-Z][a-zA-Z0-9_-]*$",
          "description": "Unique identifier for the input"
        },
        "description": {
          "type": "string"
        },
        "default": {
          "type": "string"
        },
        "password": {
          "type": "boolean",
          "description": "If true, the input should be masked",
          "default": true
        }
      }
    },
    "pickStringInput": {
      "type": "object",
      "description": "Configuration for selection from predefined options",
      "required": ["type", "id", "options"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "type": "string",
          "const": "pickString"
        },
        "id": {
          "type": "string",
          "pattern": "^[a-zA-Z][a-zA-Z0-9_-]*$",
          "description": "Unique identifier for the input"
        },
        "description": {
          "type": "string"
        },
        "options": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "minItems": 1
        },
        "default": {
          "type": "string"
        }
      }
    },
    "commandInput": {
      "type": "object",
      "description": "Configuration for command execution input",
      "required": ["type", "id", "command"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "type": "string",
          "const": "command"
        },
        "id": {
          "type": "string",
          "pattern": "^[a-zA-Z][a-zA-Z0-9_-]*$",
          "description": "Unique identifier for the input"
        },
        "command": {
          "type": "string",
          "description": "Command to execute"
        },
        "args": {
          "type": "array",
          "description": "Command arguments",
          "items": {
            "type": "string"
          }
        }
      }
    },
    "input": {
      "oneOf": [
        { "$ref": "#/definitions/promptStringInput" },
        { "$ref": "#/definitions/pickStringInput" },
        { "$ref": "#/definitions/commandInput" }
      ]
    },
    "stdioServer": {
      "type": "object",
      "description": "Configuration for STDIO server",
      "required": ["command"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "type": "string",
          "const": "stdio"
        },
        "command": {
          "type": "string",
          "description": "Command to start the server"
        },
        "cwd": {
          "type": "string",
          "description": "The working directory for the server command",
          "default": "${workspaceFolder}"
        },
        "args": {
          "type": "array",
          "description": "Command arguments",
          "items": {
            "type": "string"
          }
        },
        "env": {
          "type": "object",
          "description": "Environment variables passed to the server",
          "additionalProperties": {
            "type": ["null","string", "number"]
          }
        },
        "envFile": {
          "type": "string",
          "description": "Path to environment variables file",
          "examples": [ "${workspaceFolder}/.env" ]
        }
      }
    },
    "httpServer": {
      "type": "object",
      "description": "Configuration for Streamable HTTP or SSE endpoint",
      "required": ["url"],
      "additionalProperties": true,
      "properties": {
        "type": {
          "type": "string",
          "enum": ["http","sse"],
          "description": "The type of endpoint"
        },
        "url": {
          "type": "string",
          "format": "uri",
          "description": "The URL of the Streamable HTTP or SSE endpoint"
        },
        "headers": {
          "type": "object",
          "description": "Additional HTTP headers to send with requests",
          "additionalProperties": {
            "type": "string"
          }
        }
      }
    },
    "server": {
      "oneOf": [
        {
          "$ref": "#/definitions/stdioServer"
        },
        {
          "$ref": "#/definitions/httpServer"
        }
      ]
    }
  }
}

Thanks for this Tim - it's kinda crazy that it's so hard to find one of these still. One nit:

• for the name of each server under the servers property, NuGet treats . as an allowed character but this schema doesn't:

vs

Is this consistent with other users of the mcp.json file?