{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api-evangelist.github.io/mcp/json-schema/mcp-call-tool-schema.json",
  "title": "MCP tools/call Request and Result",
  "description": "Invokes a tool exposed by an MCP server. The server returns a CallToolResult containing one or more content blocks.",
  "oneOf": [
    { "$ref": "#/$defs/CallToolRequest" },
    { "$ref": "#/$defs/CallToolResult" }
  ],
  "$defs": {
    "CallToolRequest": {
      "type": "object",
      "required": ["jsonrpc", "id", "method", "params"],
      "properties": {
        "jsonrpc": { "const": "2.0" },
        "id": { "oneOf": [{ "type": "string" }, { "type": "integer" }] },
        "method": { "const": "tools/call" },
        "params": {
          "type": "object",
          "required": ["name"],
          "properties": {
            "name": { "type": "string" },
            "arguments": { "type": "object" },
            "_meta": { "type": "object" }
          }
        }
      }
    },
    "CallToolResult": {
      "type": "object",
      "required": ["content"],
      "properties": {
        "content": {
          "type": "array",
          "items": { "$ref": "#/$defs/ContentBlock" }
        },
        "structuredContent": {
          "type": "object",
          "description": "Optional structured output matching the tool's outputSchema."
        },
        "isError": {
          "type": "boolean",
          "description": "True when the tool returned an application-level error rather than a JSON-RPC transport error."
        },
        "_meta": { "type": "object" }
      }
    },
    "ContentBlock": {
      "oneOf": [
        { "$ref": "#/$defs/TextContent" },
        { "$ref": "#/$defs/ImageContent" },
        { "$ref": "#/$defs/AudioContent" },
        { "$ref": "#/$defs/EmbeddedResource" },
        { "$ref": "#/$defs/ResourceLink" }
      ]
    },
    "TextContent": {
      "type": "object",
      "required": ["type", "text"],
      "properties": {
        "type": { "const": "text" },
        "text": { "type": "string" },
        "annotations": { "type": "object" }
      }
    },
    "ImageContent": {
      "type": "object",
      "required": ["type", "data", "mimeType"],
      "properties": {
        "type": { "const": "image" },
        "data": { "type": "string", "contentEncoding": "base64" },
        "mimeType": { "type": "string" }
      }
    },
    "AudioContent": {
      "type": "object",
      "required": ["type", "data", "mimeType"],
      "properties": {
        "type": { "const": "audio" },
        "data": { "type": "string", "contentEncoding": "base64" },
        "mimeType": { "type": "string" }
      }
    },
    "EmbeddedResource": {
      "type": "object",
      "required": ["type", "resource"],
      "properties": {
        "type": { "const": "resource" },
        "resource": { "type": "object" }
      }
    },
    "ResourceLink": {
      "type": "object",
      "required": ["type", "uri"],
      "properties": {
        "type": { "const": "resource_link" },
        "uri": { "type": "string", "format": "uri" },
        "name": { "type": "string" },
        "mimeType": { "type": "string" }
      }
    }
  }
}