MCP SSH Manager

Instructions

Implementation Reference

• src/tool-registry.js:23-28 (registration)

  The 'ssh_session_send' tool is registered/listed in the 'sessions' group within the central tool registry manifest used for conditional registration and validation.

  sessions: [
    'ssh_session_start',
    'ssh_session_send',
    'ssh_session_list',
    'ssh_session_close'
  ],

• src/session-manager.js:151-226 (helper)

  Core implementation for executing/sending commands in a persistent SSH session. This is the primary logic behind the ssh_session_send tool: sends command via shell.write, waits for prompt, parses output, handles state/context.

  async execute(command, options = {}) {
    if (this.state !== SESSION_STATES.READY) {
      throw new Error(`Session ${this.id} is not ready (state: ${this.state})`);
    }
  
    this.state = SESSION_STATES.BUSY;
    this.lastActivity = new Date();
  
    try {
      // Clear buffers
      this.outputBuffer = '';
      this.errorBuffer = '';
  
      // Add to history unless silent
      if (!options.silent) {
        this.context.history.push({
          command,
          timestamp: new Date(),
          cwd: this.context.cwd
        });
  
        logger.info(`Session ${this.id} executing`, {
          command: command.substring(0, 100),
          server: this.serverName
        });
      }
  
      // Send command
      this.shell.write(command + '\n');
  
      // Wait for command to complete
      await this.waitForPrompt(options.timeout || 30000);
  
      // Parse output (remove command echo and prompt)
      let output = this.outputBuffer;
  
      // Remove the command echo (first line)
      const lines = output.split('\n');
      if (lines[0].includes(command)) {
        lines.shift();
      }
  
      // Remove the prompt (last line)
      const lastLine = lines[lines.length - 1];
      if (lastLine.match(/[$#>]\s*$/)) {
        lines.pop();
      }
  
      output = lines.join('\n').trim();
  
      // Check for command success (basic heuristic)
      const success = !this.errorBuffer && !output.includes('command not found');
  
      // Update context if command might have changed it
      if (command.startsWith('cd ') || command.startsWith('export ')) {
        await this.updateContext();
      }
  
      this.state = SESSION_STATES.READY;
  
      return {
        success,
        output,
        error: this.errorBuffer,
        session: this.id
      };
  
    } catch (error) {
      this.state = SESSION_STATES.ERROR;
      logger.error(`Session ${this.id} execution failed`, {
        command,
        error: error.message
      });
      throw error;
    }
  }

• src/session-manager.js:314-326 (helper)

  Retrieves an active SSH session by ID, which would be called by the ssh_session_send handler to access the session before sending a command.

  export function getSession(sessionId) {
    const session = sessions.get(sessionId);
  
    if (!session) {
      throw new Error(`Session ${sessionId} not found`);
    }
  
    if (session.state === SESSION_STATES.CLOSED) {
      throw new Error(`Session ${sessionId} is closed`);
    }
  
    return session;
  }