MCP-JSONRPC-32603 Internal Error Troubleshooting Guide

Overview

MCP-JSONRPC-32603 indicates an internal error occurred in the MCP server while executing a tool call. This is a server-side implementation issue, not a client parameter error.

Error Response Format

{
  "jsonrpc": "2.0",
  "id": 42,
  "error": {
    "code": -32603,
    "message": "Internal error",
    "data": {
      "error": "database connection failed"
    }
  }
}

Common Causes and Solutions

Cause 1: Database Connection Failure

Solution: Check database service status and network connectivity.

Cause 2: Insufficient Server Resources

Solution: Check memory and CPU usage, restart the service.

Cause 3: Code Exception

Solution: Check server logs to locate specific errors.

Cause 4: Dependency Service Unavailable

Solution: Check external API and service status.

Debugging Methods

1. Check MCP server logs
2. Monitor system resource usage
3. Verify dependency service status
4. Restart MCP server

Reference Sources

• MCP Error Codes - mcpevals.io
• MCP Debugging Guide
• JSON-RPC 2.0 Specification