Describe the problem/error/question
Hi, I have an AI agent. I’m trying to create to let the AI agent use a MCP Client tool block. However, it keeps failing with the error : Could not connect to your MCP server. I’ve tried a local mcp server which is working well but n8n just doesnt want to connect to it. Additionally i’ve tried free mcp servers and its still the same result. I’ve even tried exposing the mcps below behind and mcp server trigger yet its the same result.
i. https://learn.microsoft.com/api/mcp
ii. https://learn.microsoft.com/api/mcp
iii. https://learn.microsoft.com/api/sse
The n8n mcp client block at MCP Client Tool node documentation | n8n Docs contains little to no information.
Terminal logs don’t show any diagnostic logs except for
”Could not connect to your MCP server
McpClientTool: Failed to connect to MCP Server”
I went through existing questions and it seems like they have a different setup with docker, or coolify and with the gzip compression issues but doesn’t seem to apply to my very simple workflow.
Is there an expeced format or standardization that n8n expects?
What is the error message (if any)?
Could not connect to your MCP server
Please share your workflow
(Select the nodes on your canvas and use the keyboard shortcuts CMD+C/CTRL+C and CMD+V/CTRL+V to copy and paste the workflow.)
{
"nodes": [
{
"parameters": {
"options": {}
},
"type": "@n8n/n8n-nodes-langchain.chatTrigger",
"typeVersion": 1.1,
"position": [
0,
0
],
"id": "bc796669-8ccb-4441-97e1-6feac5925eea",
"name": "When chat message received",
"webhookId": "77ca8878-9e28-49d7-b5bd-153a4c685d48"
},
{
"parameters": {
"options": {}
},
"type": "@n8n/n8n-nodes-langchain.agent",
"typeVersion": 1.9,
"position": [
224,
0
],
"id": "09aa9de5-28e6-4a35-bcfd-6319ae2b343e",
"name": "AI Agent"
},
{
"parameters": {
"model": {
"__rl": true,
"value": "gpt-5",
"mode": "list",
"cachedResultName": "gpt-5"
},
"options": {}
},
"type": "@n8n/n8n-nodes-langchain.lmChatOpenAi",
"typeVersion": 1.2,
"position": [
272,
224
],
"id": "56b2c197-679b-4755-ad53-e0af08724b33",
"name": "OpenAI Chat Model",
"credentials": {
"openAiApi": {
"id": "Gd1YiXSSE6YfcsHN",
"name": "OpenAi account"
}
}
},
{
"parameters": {},
"type": "@n8n/n8n-nodes-langchain.memoryBufferWindow",
"typeVersion": 1.3,
"position": [
384,
352
],
"id": "1b56ad9a-14d8-4783-a3e0-d5fe9df4a562",
"name": "Simple Memory"
},
{
"parameters": {
"endpointUrl": "https://learn.microsoft.com/api/mcp",
"options": {}
},
"type": "@n8n/n8n-nodes-langchain.mcpClientTool",
"typeVersion": 1.2,
"position": [
592,
240
],
"id": "b1d8c9a3-1308-430d-a7bf-55be72a50e13",
"name": "MCP Client"
}
],
"connections": {
"When chat message received": {
"main": [
[
{
"node": "AI Agent",
"type": "main",
"index": 0
}
]
]
},
"OpenAI Chat Model": {
"ai_languageModel": [
[
{
"node": "AI Agent",
"type": "ai_languageModel",
"index": 0
}
]
]
},
"Simple Memory": {
"ai_memory": [
[
{
"node": "AI Agent",
"type": "ai_memory",
"index": 0
}
]
]
},
"MCP Client": {
"ai_tool": [
[
{
"node": "AI Agent",
"type": "ai_tool",
"index": 0
}
]
]
}
},
"pinData": {},
"meta": {
"templateCredsSetupCompleted": true,
"instanceId": "a8c68e0c7449cebebe49fb43599a88a807829a13511ac38ca33786fb12b609ec"
}
}
Share the output returned by the last node
Information on your n8n setup
- n8n version: 1.118.2
- Database (default: SQLite): SQLite
- n8n EXECUTIONS_PROCESS setting (default: own, main): Untouched from the default npm installation
- Running n8n via (Docker, npm, n8n cloud, desktop app): npm
- Operating system: windows 11
