qwen-code/docs/users/mcp/mcp-testing-validation.md

MCP Testing & Validation Guide

This guide helps you test and validate your MCP server configurations.

✅ Quick Validation Checklist

1. Check MCP Servers Are Configured

qwen mcp list

Expected output:

Configured MCP servers:

✓ filesystem: npx -y @modelcontextprotocol/server-filesystem ./ (stdio) - Connected
✓ memory: npx -y @modelcontextprotocol/server-memory (stdio) - Connected

Status indicators:

• ✓ (green) - Connected successfully
• ✗ (red) - Connection failed or not connected

2. Verify Server Is Installed

Test the server command directly:

# Filesystem server
npx -y @modelcontextprotocol/server-filesystem --help

# Memory server
npx -y @modelcontextprotocol/server-memory --help

# Custom server
python mcp_server.py --help

3. Check Configuration File Syntax

Validate your JSON configuration:

# Linux/macOS
cat .qwen/settings.json | jq .

# Windows PowerShell
Get-Content .qwen/settings.json | ConvertFrom-Json | ConvertTo-Json

4. Test Within Qwen Code Session

Start an interactive session and check MCP status:

qwen

# Inside the session:
/mcp              # Show all MCP servers and tools
/mcp desc         # Show tool descriptions
/mcp schema       # Show tool parameter schemas

🧪 Test Cases

Test Case 1: Filesystem Server

Configuration:

{
  "mcpServers": {
    "test-fs": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "./"],
      "trust": true
    }
  }
}

Validation:

1. List files: Start qwen and ask "List all files in this directory"
2. Read file: "Read the README.md file"
3. Verify output contains actual file contents

Expected Tools:

• read_file - Read file contents
• write_file - Write to files
• list_directory - List directory contents
• create_directory - Create directories
• move_file - Move/rename files
• search_files - Search for files
• get_file_info - Get file metadata

Test Case 2: Memory Server

Configuration:

{
  "mcpServers": {
    "test-memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"],
      "trust": true
    }
  }
}

Validation:

1. Store information: "Remember that this project uses React 18"
2. Query: "What JavaScript framework does this project use?"
3. Verify it recalls the information from step 1

Expected Tools:

• create_entities - Create knowledge entities
• create_relations - Create relationships between entities
• add_observations - Add observations to entities
• delete_entities - Remove entities
• delete_observations - Remove observations
• delete_relations - Remove relationships
• read_graph - Read entire knowledge graph
• search_nodes - Search for specific nodes
• open_nodes - Open specific nodes by name

Test Case 3: Multiple Servers

Configuration:

{
  "mcpServers": {
    "files": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "./"],
      "trust": true
    },
    "memory": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-memory"],
      "trust": true
    }
  }
}

Validation:

1. Check both servers are connected: qwen mcp list
2. Use filesystem tool: "List all JavaScript files"
3. Use memory tool: "Remember that we prefer TypeScript"
4. Verify both tools work simultaneously

Test Case 4: Tool Filtering

Configuration:

{
  "mcpServers": {
    "readonly-fs": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "./"],
      "includeTools": ["read_file", "list_directory"],
      "trust": true
    }
  }
}

Validation:

1. Start qwen session
2. Run /mcp desc to list available tools
3. Verify only read_file and list_directory are present
4. Verify write_file, create_directory, etc. are NOT available

Test Case 5: Untrusted Server Confirmation

Configuration:

{
  "mcpServers": {
    "untrusted": {
      "command": "npx",
      "args": ["-y", "@modelcontextprotocol/server-filesystem", "./"],
      "trust": false
    }
  }
}

Validation:

1. Ask qwen to read a file
2. Confirmation dialog should appear before execution
3. Options should include:
   • Proceed once
   • Always allow this tool
   • Always allow this server
   • Cancel

🔍 Debugging Failed Connections

Issue: Server Shows "Disconnected"

Diagnostic steps:

1. Test command manually:

   npx -y @modelcontextprotocol/server-filesystem ./
   

2. Check for errors:

   qwen --debug
   

3. Verify paths are correct:

   # Check if directory exists
   ls ./
   
   # Check if command is in PATH
   which npx  # Linux/macOS
   where npx  # Windows
   

4. Check permissions:

   # Verify read/execute permissions
   ls -la ./
   

5. Review environment variables:

   echo $PATH
   echo $PYTHONPATH  # For Python servers
   

Issue: No Tools Discovered

Diagnostic steps:

1. Verify server implements MCP protocol:

   # For stdio servers, test input/output manually
   echo '{"jsonrpc": "2.0", "method": "initialize", "id": 1}' | npx -y @modelcontextprotocol/server-filesystem ./
   

2. Check server logs:

   # Some servers log to stderr
   qwen --debug 2>&1 | grep MCP
   

3. Verify server version:

   npm list -g @modelcontextprotocol/server-filesystem
   

Issue: Tools Fail to Execute

Diagnostic steps:

1. Check parameter format:

   • Ensure parameters match the expected schema
   • Verify JSON encoding is correct

2. Increase timeout:

   {
     "mcpServers": {
       "slow-server": {
         "command": "...",
         "timeout": 60000
       }
     }
   }
   

3. Check server implementation:

   • Verify the server actually implements the tool
   • Test the tool independently if possible

📊 Validation Results

Expected Server Connection Times

Server Type	Typical Connection Time	Timeout Recommendation
Filesystem	< 1 second	10-30 seconds
Memory	< 1 second	10-30 seconds
HTTP/SSE	1-3 seconds	30-60 seconds
Custom Python	2-5 seconds	30-60 seconds
Docker	5-10 seconds	60-120 seconds

Tool Execution Times

Tool Type	Typical Duration	Timeout Recommendation
Read file	< 100ms	5-10 seconds
List directory	< 500ms	10-15 seconds
Search files	1-5 seconds	30-60 seconds
Memory operations	< 1 second	10-30 seconds
API calls	1-10 seconds	30-120 seconds

🎯 Success Criteria

Your MCP configuration is working correctly if:

✅ qwen mcp list shows all servers as "Connected" ✅ /mcp command in qwen session displays tools ✅ Tool executions complete without errors ✅ Confirmation dialogs appear for untrusted servers (if trust: false) ✅ Tool filtering works as expected (include/exclude) ✅ Environment variables are properly substituted ✅ Timeouts are appropriate for your server's response time

🚀 Performance Tips

1. Use trust: true for local servers to skip confirmation dialogs
2. Set appropriate timeouts - too low causes failures, too high slows down errors
3. Filter tools - Only enable tools you actually need
4. Test servers independently before configuring in qwen
5. Use --debug flag during initial setup
6. Monitor resource usage for long-running or resource-intensive servers

📝 Validation Script Example

Create a test script to automate validation:

#!/bin/bash
# validate-mcp.sh

echo "Testing MCP configuration..."

# Test 1: Check config file exists
if [ ! -f .qwen/settings.json ]; then
    echo "❌ Missing .qwen/settings.json"
    exit 1
fi
echo "✅ Config file exists"

# Test 2: Validate JSON syntax
if ! cat .qwen/settings.json | jq . > /dev/null 2>&1; then
    echo "❌ Invalid JSON in settings.json"
    exit 1
fi
echo "✅ Valid JSON syntax"

# Test 3: Check servers are configured
SERVER_COUNT=$(cat .qwen/settings.json | jq '.mcpServers | length')
if [ "$SERVER_COUNT" -eq 0 ]; then
    echo "❌ No MCP servers configured"
    exit 1
fi
echo "✅ $SERVER_COUNT MCP server(s) configured"

# Test 4: Check connection status
qwen mcp list | grep -q "Connected"
if [ $? -eq 0 ]; then
    echo "✅ At least one server is connected"
else
    echo "❌ No servers connected"
    exit 1
fi

echo ""
echo "✅ All validation checks passed!"

📚 Next Steps

After validation:

1. Start using MCP tools in your workflow
2. Document your custom configurations for team members
3. Share your successful configs with the community
4. Monitor performance and adjust timeouts as needed
5. Explore more MCP servers from the community

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Having issues? Check the MCP troubleshooting guide or open an issue on GitHub.