Troubleshooting

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Solution

1. Explicitly Mention Synta MCP in Your Prompt Try using a prompt like this:
   Copy

   Use synta-mcp to search for the Slack node in n8n
   
   This explicitly tells the AI to use the Synta MCP tools.
2. Restart Your AI Client
   • Completely quit your AI client (don’t just close the window)
   • Reopen the application
   • Start a new conversation/chat
3. Start a Fresh Chat
   • Previous conversations may have context that doesn’t include MCP awareness
   • Create a new chat window/conversation
   • Try your request again with explicit mention of synta-mcp
4. Verify MCP Connection
   • Check your MCP configuration is still active
   • Look for MCP indicators in your client (e.g., tool icons, MCP badge)
   • If the connection appears inactive (e.g. A red status icon on Cursor), restart your client or reconfigure following the installation steps

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Why This Happens

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Solution

1. Delete the MCP app from ChatGPT settings
2. Re-create the app following the installation steps
3. Repeat the process 3-5 times if it doesn’t work initially
4. This is a known ChatGPT limitation, not a Synta issue

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Why This Happens

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Note

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Common Symptoms

• Tools work initially, then suddenly fail with “Resource not found”
• ChatGPT reports the MCP link is “gone” mid-conversation
• Tools like n8n_get_workflow or n8n_update_partial_workflow stop working
• Connection appears to drop without warning

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Solution

1. Do NOT use ChatGPT Projects for Synta MCP
2. Use regular chat conversations (vanilla chat) instead
3. The MCP connection is more stable in standard chat mode

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Why This Happens

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Alternative Recommendation

• Cursor - Excellent MCP support with OAuth or API key
• Claude Desktop - Native MCP support, very stable
• Claude Code - CLI-based, reliable MCP integration

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Solution

1. Verify Synta API Key
   • Ensure you copied the full API key from synta.io/mcp
   • Check for extra spaces or newlines
   • Make sure the key starts with the correct format
2. Check N8N Credentials
   • Verify your N8N instance URL is accessible
   • Test your N8N API key in a browser or API client
   • Ensure the API key has the correct permissions
3. Verify N8N Login Credentials (for self-healing tools)
   • Check X-N8n-Login-Email is set to your n8n account email
   • Check X-N8n-Login-Password is set to your n8n account password
   • Required for n8n_trigger_execution and n8n_manage_pindata
   • Make sure the credentials are correct and the account has appropriate permissions
4. Update Configuration
   • Replace credentials in your config file
   • Restart your AI agent after updating

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Common Causes

• Long-running operations (large workflows, many templates)
• Network instability
• Server timeout settings
• Resource-intensive tool calls

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Solution

1. Break Down Large Operations
   • Search templates in smaller batches (use limit parameter)
   • Process workflows one at a time instead of bulk operations
   • Use pagination with cursor for large result sets
2. Use Faster Tool Variants
   • Use get_node with detail: "minimal" for quick property checks
   • Use validate_node with mode: "minimal" instead of full validation
   • Use get_template with mode: "nodes_only" for quick previews
3. Increase Timeout Settings
   • Check your MCP client’s timeout configuration
   • Some operations like n8n_trigger_execution may need longer timeouts
4. Restart the Connection
   • Clear npx cache: rm -rf ~/.npm/_npx
   • Restart your AI agent
   • Verify network stability
5. Check Tool Parameters
   • Ensure limit parameters are reasonable (avoid requesting 1000+ items)
   • Avoid includeConfigExamples in get_node unless needed
   • Disable expensive options like includeTypeInfo unless needed

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Choose the Right Tool

• Requires N8N login credentials (X-N8n-Login-Email, X-N8n-Login-Password)
• Supports all trigger types: Manual, Chat, Webhook, Form
• AI automatically detects errors and suggests fixes (self-healing)
• Full execution data for debugging
• Works with n8n_manage_pindata for testing

• External testing for activated workflows
• Supports: Webhook, Form, Chat triggers

• Requires N8N login credentials (X-N8n-Login-Email, X-N8n-Login-Password)
• Save mock data for any node and reuse in test runs
• Test webhooks/forms without sending real requests
• Skip API calls during development with saved responses
• Modes: addPinData, updatePinData, removePinData, readPinData

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Common Solutions

1. Activate Workflow (for n8n_test_workflow)
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   {
     "id": "workflow-id",
     "operations": [
       {"type": "updateSettings", "settings": {"active": true}}
     ]
   }
   
2. Verify Trigger Configuration
   • Workflow has a valid trigger node
   • Webhook path is correctly configured
   • Chat triggers have a valid chatMessage
3. Debug Failed Executions
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   // Get error details
   n8n_manage_executions({action: "get", id: "exec-id", mode: "error"})
   
   // Trace multi-workflow chains
   n8n_manage_executions({action: "correlate", executionId: "exec-id"})
   
   // Re-run failed execution
   n8n_manage_executions({action: "retry", id: "exec-id"})
   

• Failure in MCP tool execution: connection closed: calling "tools/call": client is closing: standalone SSE stream: failed to decode event: unmarshaling jsonrpc message: unexpected end of JSON input
• Failure in MCP tool execution: connection closed: calling "tools/call": client is closing: EOF
• mismatching session IDs

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Solution

1. Remove and re-add the MCP server in Antigravity
   • Go to Antigravity settings → MCP Servers
   • Remove the Synta MCP server completely
   • Close Antigravity entirely (not just the conversation)
   • Reopen Antigravity and re-add the server
2. Use the correct configuration format
   Copy

   {
     "mcpServers": {
       "synta": {
         "type": "streamable-http",
         "serverUrl": "https://mcp.synta.io/mcp"
       }
     }
   }
   
   Setting "type": "streamable-http" explicitly tells Antigravity to use the correct transport protocol.
3. If errors persist after re-adding, start a new conversation in Antigravity. The previous conversation may have cached stale session state.

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Why This Happens

“This tool has been disabled in your connector settings.”

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Why This Happens

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Fix

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Why This Happens

• The workflow uses nodes from a newer n8n version
• Community nodes are not installed
• Node packages are missing or outdated

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Solution

1. Update n8n to Latest Version
   • Check your current version in Settings → About n8n
   • Update to the latest version:
   n8n Cloud: Automatically updated, contact support if issues persist Self-hosted: Follow your hosting provider’s instructions for updating n8n (Docker, npm, etc.)
2. Install Missing Community Nodes
   • Go to Settings → Community nodes
   • Search for and install any missing community nodes
   • Restart n8n after installation
3. Check Node Compatibility
   • Some nodes may be deprecated or renamed in newer versions
   • Use n8n_autofix_workflow to automatically update node types
   • Review the workflow and replace deprecated nodes with current alternatives

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Solution

rm -rf ~/.npm/_npx

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Why This Happens

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Solution by Client

mkdir -p ~/.cursor && touch ~/.cursor/mcp.json

mkdir -p ~/Library/Application\ Support/Claude
touch ~/Library/Application\ Support/Claude/claude_desktop_config.json

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Solution

[mcp_servers.synta-mcp]
# ... your existing configuration ...
startup_timeout_sec = 30
tool_timeout_sec = 360

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Alternative: Increase Startup Timeout

[mcp_servers.synta-mcp]
# ... your existing configuration ...
startup_timeout_sec = 40
tool_timeout_sec = 360

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Why This Happens

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After Updating

1. Save your config.toml file
2. Restart your terminal or Codex session
3. Verify with: codex mcp list

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Solution

1. Check Internet Connection
   • Ensure you have a stable internet connection
   • Try accessing the MCP server URL in a browser
2. Firewall/Proxy Settings
   • Check if your firewall is blocking the connection
   • If using a corporate proxy, ensure npx can access external URLs
   • You may need to configure proxy settings in your environment
3. N8N Instance Accessibility
   • Verify your N8N instance is running and accessible
   • Test the URL in a browser: https://your-instance/api/v1/health
   • Check if the instance requires VPN or special network access