Moralis MCP Server

Instructions

Implementation Reference

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

  The core handler function `executeApiTool` that implements the logic for calling the external Moralis API for any tool, including `evm_getpairstats`. It handles input validation with Zod (derived from OpenAPI schema), constructs HTTP requests (URL, params, headers, body, auth), executes via axios, and formats the response or errors.

  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/parser/extract-tools.ts:101-180 (schema)

  `generateInputSchemaAndDetails` creates the JSON Schema (`inputSchema`) for tool input validation from the OpenAPI operation's parameters and requestBody. This schema is used by the handler for `evm_getpairstats`.

  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/parser/extract-tools.ts:17-93 (registration)

  `extractToolsFromApi` scans OpenAPI paths/operations, generates tool names (with prefix like 'evm_'), extracts schemas/security/etc., producing `McpToolDefinition` for `evm_getpairstats` from the EVM spec.

  export function extractToolsFromApi(
    api: OpenAPIV3DocumentX,
    prefix?: string
  ): McpToolDefinition[] {
    const tools: McpToolDefinition[] = [];
    const usedNames = new Set<string>();
    const globalSecurity = api.security || [];
  
    if (!api.paths) return tools;
  
    for (const [path, pathItem] of Object.entries(api.paths)) {
      if (!pathItem) continue;
  
      for (const method of Object.values(OpenAPIV3.HttpMethods)) {
        const operation = pathItem[method];
        if (!operation) continue;
  
        // Generate a unique name for the tool
        let baseName = operation.operationId || generateOperationId(method, path);
        if (!baseName) continue;
  
        // Sanitize the name to be MCP-compatible (only a-z, 0-9, _, -)
        baseName = baseName
          .replace(/\./g, '_')
          .replace(/[^a-z0-9_-]/gi, '_')
          .toLowerCase();
  
        let finalToolName = baseName;
        let counter = 1;
        while (usedNames.has(finalToolName)) {
          finalToolName = `${baseName}_${counter++}`;
        }
        usedNames.add(finalToolName);
  
        // Get or create a description
        const description =
          operation.description ||
          operation.summary ||
          `Executes ${method.toUpperCase()} ${path}`;
  
        const prompt = operation['x-mcp-prompt'];
  
        // Generate input schema and extract parameters
        const { inputSchema, parameters, requestBodyContentType } =
          generateInputSchemaAndDetails(operation);
  
        // Extract parameter details for execution
        const executionParameters = parameters.map((p) => ({
          name: p.name,
          in: p.in,
        }));
  
        // Determine security requirements
        const securityRequirements =
          operation.security === null
            ? globalSecurity
            : operation.security || globalSecurity;
  
        // Create the tool definition
        tools.push({
          name: prefix + finalToolName,
          description,
          inputSchema,
          method,
          pathTemplate: path,
          parameters,
          executionParameters,
          requestBodyContentType,
          securityRequirements,
          operationId: baseName,
          prompt,
        });
      }
    }
  
    return tools;
  }

• src/server.ts:96-120 (registration)

  Registers the MCP `CallToolRequestSchema` handler on the server, which retrieves the tool definition by name (`evm_getpairstats`) from `toolDefinitionMap` and calls `executeApiTool`.

  server.setRequestHandler(
    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,
      );
    },
  );

• src/config.ts:15-22 (helper)

  Defines `evm` config with `prefix: 'evm_'` and `specUrl` pointing to Moralis EVM OpenAPI spec (containing the `getpairstats` operation), used by `mapToolDefinitions` to register EVM tools.

  evm:  {
    prefix: 'evm_',
    baseUrl:
      process.env.API_BASE_URL || 'https://deep-index.moralis.io/api/v2.2',
    specUrl:
      process.env.API_SPEC_URL ||
      'https://deep-index.moralis.io/api-docs-2.2/v2.2/swagger.json',
  },