n8n MCP Server Trigger: give Claude a video tool

n8n's MCP Server Trigger node turns an n8n workflow into an MCP server: it exposes an MCP URL that clients such as Claude connect to, and the tool nodes attached to it are the tools the client can list and call. To give Claude a video tool, attach a Call n8n Workflow Tool node whose sub-workflow calls a video API over HTTPS, with the API key stored in n8n.

n8n facts come from its MCP Server Trigger and Call n8n Workflow Tool docs, Claude Code facts from its MCP docs, and Sume facts from the MCP overview and Video generation docs, all read on 2026-09-28. Sume has no official n8n node; the video call below is a plain HTTP request.

How does the n8n MCP Server Trigger work?

Unlike other triggers, it does not pass output to a next node. It only connects to and runs tool nodes, and a whole workflow becomes a tool through the Call n8n Workflow Tool node. That node's Description tells the model when to use the tool.

How do I connect Claude to an n8n MCP server?

In Claude Code, add the production MCP URL as a remote HTTP server and pass the Bearer token from the trigger's credential as a header. Claude Code tries HTTP first and falls back to SSE when the server doesn't accept it; that automatic switch needs Claude Code v2.1.265 or later.

• Claude Desktop: n8n's page shows a gateway config that runs mcp-remote with your MCP URL and token.
• claude.ai custom connectors ask you to sign in to n8n even when Authentication is None; n8n says claude.ai is the only client known to do this.

claude mcp add --transport http n8n-video <MCP_URL> \
  --header "Authorization: Bearer <MCP_BEARER_TOKEN>"

How do I make the tool generate a video?

In the sub-workflow, an HTTP Request node POSTs to https://api.sume.com/v1/videos with a Bearer credential that holds $SUME_API_KEY, and a body such as {"model": "kling-3", "prompt": "...", "duration": 5}. Sume answers 202 with a job id and a polling_url. Keeping the call in n8n keeps the key out of the client config, in line with Sume's rule to keep keys on trusted servers or secret stores.

Video generation typically takes 30 seconds to several minutes, which is a long time for one tool call to block. One design is two tools: one that submits and returns the job id, and one that reads GET /v1/videos/{jobId} and returns the status. Once it is completed, the file comes from GET /v1/videos/{jobId}/content, which also needs the key. Kling API in n8n covers the node settings, polling, and the download step.

Do I need n8n if Claude only has to make videos?

No. Sume runs a hosted MCP server at https://mcp.sume.com/mcp for Claude Code and other remote MCP clients, with paid tools such as generate_video. Over OAuth it is read-only until you opt in to mcp:write on the consent page; an API key sees the full tool set. Sume's docs say hosted MCP still works but is not part of the primary path today, and not the default integration. Sume MCP server for Claude Code covers that setup.

The n8n route earns its place when the tool is your own multi-step job: generate, wait, save the file, notify a channel. For the opposite direction, n8n calling Sume's MCP server, see n8n MCP Client Tool with Sume.

What are the MCP Server Trigger's limits?

These come from n8n's own docs; check them against your n8n version.

• In queue mode with several webhook replicas, route all /mcp* requests to one dedicated replica, or SSE and streamable HTTP connections break.
• Behind a reverse proxy such as nginx, turn off proxy buffering for the MCP endpoint.
• When the workflow tool picks its sub-workflow from the database and runs in production, that sub-workflow must be published, or the call fails with Workflow is not active and cannot be executed.