MCP- N8N

Instructions

Implementation Reference

• src/index.ts:1457-1487 (handler)

  Handler for the 'delete-variable' tool in the CallToolRequestSchema switch statement. Validates client existence, calls the N8nClient.deleteVariable method, and returns success or error response.

  case "delete-variable": {
    const { clientId, id } = args as { clientId: string; id: string };
    const client = clients.get(clientId);
    if (!client) {
      return {
        content: [{
          type: "text",
          text: "Client not initialized. Please run init-n8n first.",
        }],
        isError: true
      };
    }
  
    try {
      await client.deleteVariable(id);
      return {
        content: [{
          type: "text",
          text: `Successfully deleted variable with ID: ${id}`,
        }]
      };
    } catch (error) {
      return {
        content: [{
          type: "text",
          text: error instanceof Error ? error.message : "Unknown error occurred",
        }],
        isError: true
      };
    }
  }

• src/index.ts:262-266 (helper)

  Helper method in N8nClient class that performs the actual API DELETE request to remove a variable by ID.

  async deleteVariable(id: string): Promise<void> {
    return this.makeRequest<void>(`/variables/${id}`, {
      method: 'DELETE',
    });

• src/index.ts:639-650 (registration)

  Tool definition registered in the ListToolsRequestSchema handler's tools array, specifying name, description, and input schema.

  {
    name: "delete-variable",
    description: "Delete a variable by ID. NOTE: Requires n8n Enterprise license with variable management features enabled. Use after list-variables to get the ID of the variable to delete. This action cannot be undone. IMPORTANT: Arguments must be provided as compact, single-line JSON without whitespace or newlines.",
    inputSchema: {
      type: "object",
      properties: {
        clientId: { type: "string" },
        id: { type: "string" }
      },
      required: ["clientId", "id"]
    }
  },

• src/index.ts:642-649 (schema)

  Input schema definition for the delete-variable tool, defining required parameters clientId and id.

  inputSchema: {
    type: "object",
    properties: {
      clientId: { type: "string" },
      id: { type: "string" }
    },
    required: ["clientId", "id"]
  }