MalwareAnalyzerMCP

Instructions

Implementation Reference

• serverMCP.js:130-164 (handler)

  Core handler for executing the 'xxd' tool (and other specialized commands): validates input against schema, builds command string using tool-specific buildCommand, executes via terminalManager.shellCommand, and returns result.

  if (commands[name]) {
    try {
      const cmdConfig = commands[name];
      
      // Validate arguments against schema
      const validationResult = cmdConfig.schema.safeParse(args);
      if (!validationResult.success) {
        return {
          content: [{ 
            type: "text", 
            text: `Error: Invalid parameters for ${name} command.\n${JSON.stringify(validationResult.error.format())}`
          }],
          isError: true,
        };
      }
      
      // Build the command string
      const commandStr = cmdConfig.buildCommand(validationResult.data);
      console.error(`Executing specialized command: ${commandStr}`);
      
      // Execute the command via the terminal manager
      const result = await terminalManager.shellCommand(commandStr);
      console.error(`${name} command executed with PID: ${result.pid}, blocked: ${result.isBlocked}`);
      
      return {
        content: [{ type: "text", text: JSON.stringify(result) }],
      };
    } catch (error) {
      console.error(`Error executing ${name} command:`, error);
      return {
        content: [{ type: "text", text: `Error: ${error instanceof Error ? error.message : String(error)}` }],
        isError: true,
      };
    }
  }

• commands.js:142-162 (handler)

  xxd-specific logic to construct the xxd shell command from input parameters.

  buildCommand: (args) => {
    let options = args.options ? args.options : '';
    
    if (args.length) {
      options += ` -l ${args.length}`;
    }
    
    if (args.offset) {
      options += ` -s ${args.offset}`;
    }
    
    if (args.cols) {
      options += ` -c ${args.cols}`;
    }
    
    if (args.bits) {
      options += ' -b';
    }
    
    return `xxd ${options} ${args.target}`;
  },

• commands.js:136-141 (schema)

  Zod input schema for the xxd tool, defining parameters like length, offset, cols, bits extending baseCommandSchema.

  schema: baseCommandSchema.extend({
    length: z.number().optional().describe("Number of bytes to display"),
    offset: z.number().optional().describe("Starting offset in the file"),
    cols: z.number().optional().describe("Format output into specified number of columns"),
    bits: z.boolean().optional().describe("Switch to bits (binary) dump")
  }),

• serverMCP.js:113-118 (registration)

  Registers 'xxd' (and other commands) as MCP tools dynamically from the commands configuration, providing name, description, and inputSchema.

  const specializedTools = Object.values(commands).map(cmd => ({
    name: cmd.name,
    description: cmd.description + (cmd.helpText ? '\n' + cmd.helpText : ''),
    inputSchema: zodToJsonSchema(cmd.schema),
  }));

• commands.js:132-170 (registration)

  Configuration object for the 'xxd' tool, including name, description, schema, buildCommand, and helpText, exported as part of commands.

    // XXD command - hexdump with ASCII representation
    xxd: {
      name: 'xxd',
      description: 'Create a hexdump with ASCII representation',
      schema: baseCommandSchema.extend({
        length: z.number().optional().describe("Number of bytes to display"),
        offset: z.number().optional().describe("Starting offset in the file"),
        cols: z.number().optional().describe("Format output into specified number of columns"),
        bits: z.boolean().optional().describe("Switch to bits (binary) dump")
      }),
      buildCommand: (args) => {
        let options = args.options ? args.options : '';
        
        if (args.length) {
          options += ` -l ${args.length}`;
        }
        
        if (args.offset) {
          options += ` -s ${args.offset}`;
        }
        
        if (args.cols) {
          options += ` -c ${args.cols}`;
        }
        
        if (args.bits) {
          options += ' -b';
        }
        
        return `xxd ${options} ${args.target}`;
      },
      helpText: `
  Example usage:
    - Standard xxd dump: { "target": "suspicious.exe" }
    - With length limit: { "target": "suspicious.exe", "length": 256 }
    - With column formatting: { "target": "suspicious.exe", "cols": 16 }
    - Binary bits mode: { "target": "suspicious.exe", "bits": true }
      `
    }