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Perplexity MCP Zerver (JSON Communication Fixed)

This repository contains a fixed version of the perplexity-mcp-zerver project that resolves JSON communication errors between the MCP client and server.

The Problem

The original code was producing errors like:

MCP perplexity-server: Unexpected token 'R', "Recovery completed" is not valid JSON

This happened because some log messages were being sent to stdout (using console.log) instead of stderr, which interfered with the JSON communication between the MCP client and server.

The Fix

Two specific changes were made to fix this issue:

Modified the log method to use safeLog for info messages instead of direct console.log calls:

// Before
private log(level: 'info'|'error'|'warn', message: string) {
  if (level === 'error') {
    logError(message);
  } else if (level === 'warn') {
    logWarn(message);
  } else {
    console[level](message); // Uses console.log for 'info'
  }
}

// After
private log(level: 'info'|'error'|'warn', message: string) {
  if (level === 'error') {
    logError(message);
  } else if (level === 'warn') {
    logWarn(message);
  } else {
    // Use console.error for info messages too to prevent JSON communication issues
    safeLog(message);
  }
}

Changed the "Recovery completed" message to use logError directly to ensure it's sent through stderr:

// Before
this.log('info', 'Recovery completed');

// After
// Use logError instead of log for completion message to ensure it uses stderr
logError('Recovery completed');

These changes ensure that all logging is properly separated from the JSON communication channel, preventing parsing errors while maintaining useful debug information.

Original Project

This is a fixed version of the original perplexity-mcp-zerver project, which is a Model Context Protocol (MCP) server implementation providing AI-powered research capabilities by interacting with the Perplexity website without requiring an API key.

Features

🔍 Web search integration via Perplexity's web interface.
💬 Persistent chat history for conversational context.
📄 Tools for documentation retrieval, API finding, and code analysis.
🚫 No API Key required (relies on web interaction).
🛠️ TypeScript-first implementation.
🌐 Uses Puppeteer for browser automation.

Installation and Usage

Please refer to the original project's documentation for installation and usage instructions.

License

This project is licensed under the GNU General Public License v3.0 - see the LICENSE.md file for details, consistent with the original project.

perplexity-mcp-zerver-fixed-json