Local Logs MCP Server

Instructions

Implementation Reference

• local-logs-mcp-server.js:287-328 (handler)

  The tailLog method that executes the core logic of the 'tail_log' MCP tool. It reads the last N lines from the specified log file, preferring the 'tail' command on Unix-like systems and falling back to reading the entire file on Windows or if the command fails.

  tailLog(filename = 'combined.log', lines = 50) {
    try {
      const filePath = path.join(this.logsDir, filename);
      
      if (!fs.existsSync(filePath)) {
        return { 
          content: '', 
          message: `Log file ${filename} not found. Available files: ${this.getLogFiles().files.map(f => f.name).join(', ')}`,
          filename,
          lines: 0
        };
      }
  
      let content;
      try {
        if (process.platform === 'win32') {
          const fullContent = fs.readFileSync(filePath, 'utf8');
          const allLines = fullContent.split('\n');
          content = allLines.slice(-lines).join('\n');
        } else {
          content = execSync(`tail -n ${lines} "${filePath}"`, { encoding: 'utf8' });
        }
      } catch (cmdError) {
        const fullContent = fs.readFileSync(filePath, 'utf8');
        const allLines = fullContent.split('\n');
        content = allLines.slice(-lines).join('\n');
      }
  
      const actualLines = content.split('\n').filter(line => line.trim()).length;
  
      return { 
        content, 
        message: `Last ${actualLines} lines from ${filename}`,
        filename,
        lines: actualLines,
        fileSize: fs.statSync(filePath).size,
        fileSizeHuman: this.formatBytes(fs.statSync(filePath).size)
      };
    } catch (error) {
      return { content: '', error: error.message, filename };
    }
  }

• local-logs-mcp-server.js:106-124 (registration)

  The registration of the 'tail_log' tool in the 'tools/list' RPC method response, including its name, description, and input schema.

    name: 'tail_log',
    description: 'Get the last N lines from a log file',
    inputSchema: {
      type: 'object',
      properties: {
        filename: {
          type: 'string',
          description: 'Name of the log file (default: combined.log)',
          default: 'combined.log'
        },
        lines: {
          type: 'number',
          description: 'Number of lines to return (default: 50)',
          default: 50
        }
      },
      required: []
    }
  },

• local-logs-mcp-server.js:215-217 (registration)

  The dispatch case in the 'tools/call' handler that routes 'tail_log' calls to the tailLog implementation method.

  case 'tail_log':
    result = this.tailLog(args?.filename, args?.lines);
    break;

• local-logs-mcp-server.js:108-123 (schema)

  The JSON schema defining the input parameters for the 'tail_log' tool: optional filename (string) and lines (number).

  inputSchema: {
    type: 'object',
    properties: {
      filename: {
        type: 'string',
        description: 'Name of the log file (default: combined.log)',
        default: 'combined.log'
      },
      lines: {
        type: 'number',
        description: 'Number of lines to return (default: 50)',
        default: 50
      }
    },
    required: []
  }