Moralis MCP Server

Instructions

Implementation Reference

• src/utils/execute-api-tool.ts:34-252 (handler)

  Core handler function that executes the API call for any tool, including 'evm_getdefisummary'. Validates inputs, constructs HTTP request using tool definition (path, method, params, body, auth), calls the Moralis API, and formats the response.

  export async function executeApiTool(
    toolName: string,
    definition: McpToolDefinition,
    toolArgs: JsonObject,
    allSecuritySchemes: Record<string, any>,
    token?: string,
  ): Promise<CallToolResult> {
    try {
      // Validate arguments against the input schema
      let validatedArgs: JsonObject;
      try {
        const zodSchema = getZodSchemaFromJsonSchema(
          definition.inputSchema,
          toolName,
        );
        const argsToParse =
          typeof toolArgs === 'object' && toolArgs !== null ? toolArgs : {};
        validatedArgs = zodSchema.parse(argsToParse);
      } catch (error: unknown) {
        if (error instanceof ZodError) {
          const validationErrorMessage = `Invalid arguments for tool '${toolName}': ${error.errors.map((e) => `${e.path.join('.')} (${e.code}): ${e.message}`).join(', ')}`;
          return { content: [{ type: 'text', text: validationErrorMessage }] };
        } else {
          const errorMessage =
            error instanceof Error ? error.message : String(error);
          return {
            content: [
              {
                type: 'text',
                text: `Internal error during validation setup: ${errorMessage}`,
              },
            ],
          };
        }
      }
  
      // Prepare URL, query parameters, headers, and request body
      let urlPath = definition.pathTemplate;
      const queryParams: Record<string, any> = {};
      const headers: Record<string, string> = {
        Accept: 'application/json',
        'X-Moralis-Platform': 'MCP',
      };
      let requestBodyData: any = undefined;
  
      // Apply parameters to the URL path, query, or headers
      definition.executionParameters.forEach((param) => {
        const value = validatedArgs[param.name];
        if (typeof value !== 'undefined' && value !== null) {
          if (param.in === 'path') {
            urlPath = urlPath.replace(
              `{${param.name}}`,
              encodeURIComponent(String(value)),
            );
          } else if (param.in === 'query') {
            queryParams[param.name] = value;
          } else if (param.in === 'header') {
            headers[param.name.toLowerCase()] = String(value);
          }
        }
      });
  
      // Ensure all path parameters are resolved
      if (urlPath.includes('{')) {
        throw new Error(`Failed to resolve path parameters: ${urlPath}`);
      }
  
      // Construct the full URL
      const requestUrl = `${definition.baseUrl}${urlPath}`;
  
      // Handle request body if needed
      if (
        definition.requestBodyContentType &&
        typeof validatedArgs['requestBody'] !== 'undefined'
      ) {
        requestBodyData = validatedArgs['requestBody'];
        headers['content-type'] = definition.requestBodyContentType;
      }
  
      // Apply security requirements if available
      // Security requirements use OR between array items and AND within each object
      const appliedSecurity = definition.securityRequirements?.find((req) => {
        // Try each security requirement (combined with OR)
        return Object.entries(req).every(([schemeName, scopesArray]) => {
          const scheme = allSecuritySchemes[schemeName];
          if (!scheme) return false;
  
          // API Key security (header, query, cookie)
          if (scheme.type === 'apiKey') {
            return !!token || !!Config.MORALIS_API_KEY;
          }
  
          return false;
        });
      });
  
      // If we found matching security scheme(s), apply them
      if (appliedSecurity) {
        // Apply each security scheme from this requirement (combined with AND)
        for (const [schemeName, scopesArray] of Object.entries(appliedSecurity)) {
          const scheme = allSecuritySchemes[schemeName];
  
          // API Key security
          if (scheme?.type === 'apiKey') {
            const apiKey = token || Config.MORALIS_API_KEY;
            if (apiKey) {
              if (scheme.in === 'header') {
                headers[scheme.name.toLowerCase()] = apiKey;
                console.error(
                  `Applied API key '${schemeName}' in header '${scheme.name}'`,
                );
              }
            }
          }
        }
      }
      // Log warning if security is required but not available
      else if (definition.securityRequirements?.length > 0) {
        // First generate a more readable representation of the security requirements
        const securityRequirementsString = definition.securityRequirements
          .map((req) => {
            const parts = Object.entries(req)
              .map(([name, scopesArray]) => {
                const scopes = scopesArray as string[];
                if (scopes.length === 0) return name;
                return `${name} (scopes: ${scopes.join(', ')})`;
              })
              .join(' AND ');
            return `[${parts}]`;
          })
          .join(' OR ');
  
        console.warn(
          `Tool '${toolName}' requires security: ${securityRequirementsString}, but no suitable credentials found.`,
        );
      }
  
      // Prepare the axios request configuration
      const config: AxiosRequestConfig = {
        method: definition.method.toUpperCase(),
        url: requestUrl,
        params: queryParams,
        headers: headers,
        ...(requestBodyData !== undefined && { data: requestBodyData }),
      };
  
      // Log request info to stderr (doesn't affect MCP output)
      console.error(
        `Executing tool "${toolName}": ${config.method} ${config.url}`,
      );
  
      // Execute the request
      const response = await axios(config);
  
      // Process and format the response
      let responseText = '';
      const contentType = response.headers['content-type']?.toLowerCase() || '';
  
      // Handle JSON responses
      if (
        contentType.includes('application/json') &&
        typeof response.data === 'object' &&
        response.data !== null
      ) {
        try {
          responseText = JSON.stringify(response.data, null, 2);
        } catch (e) {
          responseText = '[Stringify Error]';
        }
      }
      // Handle string responses
      else if (typeof response.data === 'string') {
        responseText = response.data;
      }
      // Handle other response types
      else if (response.data !== undefined && response.data !== null) {
        responseText = String(response.data);
      }
      // Handle empty responses
      else {
        responseText = `(Status: ${response.status} - No body content)`;
      }
  
      // Return formatted response
      return {
        content: [
          {
            type: 'text',
            text: `API Response (Status: ${response.status}):\n${responseText}`,
          },
        ],
      };
    } catch (error: unknown) {
      // Handle errors during execution
      let errorMessage: string;
  
      // Format Axios errors specially
      if (axios.isAxiosError(error)) {
        errorMessage = formatApiError(error);
      }
      // Handle standard errors
      else if (error instanceof Error) {
        errorMessage = error.message;
      }
      // Handle unexpected error types
      else {
        errorMessage = `Unexpected error: ${String(error)}`;
      }
  
      // Log error to stderr
      console.error(
        `Error during execution of tool '${toolName}':`,
        errorMessage,
      );
  
      // Return error message to client
      return { content: [{ type: 'text', text: errorMessage }] };
    }
  }

• src/server.ts:66-72 (registration)

  Populates the central toolDefinitionMap with definitions for all EVM tools (prefixed with 'evm_') by extracting from Moralis OpenAPI spec via mapToolDefinitions.

  let toolDefinitionMap: Record<string, McpToolDefinition> = {};
  for (const config of configArray)
    toolDefinitionMap = {
      ...toolDefinitionMap,
      ...(await mapToolDefinitions(config)),
    };

• src/parser/extract-tools.ts:95-180 (schema)

  Generates the inputSchema (JSON Schema) and parameter details for MCP tool definitions from OpenAPI operation objects, used for 'evm_getdefisummary' schema.

  /**
   * Generates input schema and extracts parameter details from an operation
   *
   * @param operation OpenAPI operation object
   * @returns Input schema, parameters, and request body content type
   */
  export function generateInputSchemaAndDetails(
    operation: OpenAPIV3.OperationObject,
  ): {
    inputSchema: JSONSchema7 | boolean;
    parameters: OpenAPIV3.ParameterObject[];
    requestBodyContentType?: string;
  } {
    const properties: { [key: string]: JSONSchema7 | boolean } = {};
    const required: string[] = [];
  
    // Process parameters
    const allParameters: OpenAPIV3.ParameterObject[] = Array.isArray(
      operation.parameters,
    )
      ? operation.parameters.map((p) => p as OpenAPIV3.ParameterObject)
      : [];
  
    allParameters.forEach((param) => {
      if (!param.name || !param.schema) return;
  
      const paramSchema = mapOpenApiSchemaToJsonSchema(
        param.schema as OpenAPIV3.SchemaObject,
      );
      if (typeof paramSchema === 'object') {
        paramSchema.description = param.description || paramSchema.description;
      }
  
      properties[param.name] = paramSchema;
      if (param.required) required.push(param.name);
    });
  
    // Process request body (if present)
    let requestBodyContentType: string | undefined = undefined;
  
    if (operation.requestBody) {
      const opRequestBody = operation.requestBody as OpenAPIV3.RequestBodyObject;
      const jsonContent = opRequestBody.content?.['application/json'];
      const firstContent = opRequestBody.content
        ? Object.entries(opRequestBody.content)[0]
        : undefined;
  
      if (jsonContent?.schema) {
        requestBodyContentType = 'application/json';
        const bodySchema = mapOpenApiSchemaToJsonSchema(
          jsonContent.schema as OpenAPIV3.SchemaObject,
        );
  
        if (typeof bodySchema === 'object') {
          bodySchema.description =
            opRequestBody.description ||
            bodySchema.description ||
            'The JSON request body.';
        }
  
        properties['requestBody'] = bodySchema;
        if (opRequestBody.required) required.push('requestBody');
      } else if (firstContent) {
        const [contentType] = firstContent;
        requestBodyContentType = contentType;
  
        properties['requestBody'] = {
          type: 'string',
          description:
            opRequestBody.description ||
            `Request body (content type: ${contentType})`,
        };
  
        if (opRequestBody.required) required.push('requestBody');
      }
    }
  
    // Combine everything into a JSON Schema
    const inputSchema: JSONSchema7 = {
      type: 'object',
      properties,
      ...(required.length > 0 && { required }),
    };
  
    return { inputSchema, parameters: allParameters, requestBodyContentType };
  }

• src/server.ts:85-94 (registration)

  MCP ListTools request handler that returns all registered tools including 'evm_getdefisummary' for client discovery.

  server.setRequestHandler(ListToolsRequestSchema, async () => {
    const toolsForClient: Tool[] = Object.values(toolDefinitionMap).map(
      (def) => ({
        name: def.name,
        description: def.description,
        inputSchema: def.inputSchema,
      }),
    );
    return { tools: toolsForClient };
  });

• src/server.ts:97-120 (handler)

  MCP CallTool request handler that routes tool calls (e.g. 'evm_getdefisummary') to the executeApiTool function using the stored definition.

    CallToolRequestSchema,
    async (request: CallToolRequest, c): Promise<CallToolResult> => {
      const { name: toolName, arguments: toolArgs } = request.params;
      const toolDefinition = toolDefinitionMap[toolName];
      if (!toolDefinition) {
        console.error(`Error: Unknown tool requested: ${toolName}`);
        return {
          content: [
            {
              type: 'text',
              text: `Error: Unknown tool requested: ${toolName}`,
            },
          ],
        };
      }
      return executeApiTool(
        toolName,
        toolDefinition,
        toolArgs ?? {},
        securitySchemes,
        c.authInfo?.token,
      );
    },
  );