Nessus MCP Server

Instructions

Implementation Reference

• src/tools/vulnerabilities.ts:29-73 (handler)

  The primary handler function that executes the get_vulnerability_details tool logic, including input validation, API call to fetch details, formatting, and error handling.

  export const getVulnerabilityDetailsToolHandler = async (args: Record<string, unknown>) => {
    try {
      // Validate arguments
      const vulnId = validateVulnerabilityId(args.vulnerability_id);
  
      // Get vulnerability details
      const details = await getVulnerabilityDetails(vulnId);
  
      // Check if there was an error
      if ('error' in details) {
        return {
          content: [
            {
              type: 'text',
              text: `Error: ${details.error}`
            }
          ],
          isError: true
        };
      }
  
      // Format the vulnerability details
      const formattedDetails = formatVulnerabilityDetails(details);
  
      return {
        content: [
          {
            type: 'text',
            text: formattedDetails
          }
        ]
      };
    } catch (error) {
      const mcpError = handleNessusApiError(error);
      return {
        content: [
          {
            type: 'text',
            text: `Error: ${mcpError.message}`
          }
        ],
        isError: true
      };
    }
  };

• src/tools/vulnerabilities.ts:14-27 (schema)

  Defines the input schema and metadata for the get_vulnerability_details tool.

  export const getVulnerabilityDetailsToolSchema = {
    name: 'get_vulnerability_details',
    description: 'Get detailed information about a specific vulnerability',
    inputSchema: {
      type: 'object',
      properties: {
        vulnerability_id: {
          type: 'string',
          description: 'ID of the vulnerability (e.g., CVE-2021-44228)'
        }
      },
      required: ['vulnerability_id']
    }
  };

• src/index.ts:107-108 (registration)

  Registers and dispatches the get_vulnerability_details tool handler in the main CallToolRequestSchema switch statement.

  case 'get_vulnerability_details':
    return await getVulnerabilityDetailsToolHandler(args);

• src/index.ts:71-86 (registration)

  Registers the tool schema in the ListToolsRequestSchema handler, making it discoverable.

  server.setRequestHandler(
    ListToolsRequestSchema,
    async () => {
      return {
        tools: [
          listScanTemplatesToolSchema,
          startScanToolSchema,
          getScanStatusToolSchema,
          getScanResultsToolSchema,
          listScansToolSchema,
          getVulnerabilityDetailsToolSchema,
          searchVulnerabilitiesToolSchema
        ]
      };
    }
  );

• src/nessus-api.ts:131-138 (helper)

  Supporting function called by the handler to retrieve raw vulnerability details from mock data or real Nessus API.

  export const getVulnerabilityDetails = async (vulnId: string) => {
    if (config.useMock) {
      return getMockVulnerabilityDetails(vulnId);
    }
  
    // Real API implementation would go here
    throw new Error("Real API not implemented");
  };