n8n MCP Server

Instructions

Implementation Reference

• src/n8n-client.ts:408-424 (handler)

  Core handler implementation in N8nClient that generates a node ID, computes default position if needed, constructs the new node object, and atomically appends it to the workflow's nodes array via performWorkflowUpdate.

  async createNode(request: CreateNodeRequest): Promise<CreateNodeResponse> {
    const nodeId = this.generateNodeId();
    await this.performWorkflowUpdate(request.workflowId, (workflow) => {
      const position = request.position || this.getDefaultPosition(workflow.nodes);
      const newNode: N8nNode = {
        id: nodeId,
        name: request.name || request.type.split('.').pop() || 'New Node',
        type: request.type,
        typeVersion: 1,
        position,
        parameters: request.params || {},
        credentials: request.credentials || {},
      };
      workflow.nodes.push(newNode);
    });
    return { nodeId };
  }

• src/index.ts:541-551 (handler)

  MCP server tool handler that receives the tool call, delegates to N8nClient.createNode, and formats the success response as MCP content.

  private async handleCreateNode(args: CreateNodeRequest) {
    const result = await this.n8nClient.createNode(args);
    return {
      content: [
        {
          type: 'text',
          text: JSON.stringify(jsonSuccess(result), null, 2),
        },
      ],
    };
  }

• src/index.ts:211-211 (registration)

  Tool registration in the MCP server's ListTools response, defining the tool name, description, and JSON schema for input validation.

  { name: 'create_node', description: 'Create a new node in an existing n8n workflow', inputSchema: { type: 'object', properties: { workflowId: { oneOf: [{ type: 'string' }, { type: 'number' }], description: 'The workflow ID' }, type: { type: 'string', description: 'The node type (e.g., n8n-nodes-base.webhook)' }, name: { type: 'string', description: 'Optional name for the node' }, params: { type: 'object', description: 'Optional node parameters' }, position: { type: 'array', items: { type: 'number' }, minItems: 2, maxItems: 2, description: 'Optional [x, y] position' }, credentials: { type: 'object', description: 'Optional credentials configuration' } }, required: ['workflowId', 'type'] } },

• src/types.ts:188-195 (schema)

  TypeScript interface defining the input parameters for create_node, used in handlers and registration.

  export interface CreateNodeRequest {
    workflowId: string | number;
    type: string;
    name?: string;
    params?: Record<string, any>;
    position?: [number, number];
    credentials?: Record<string, string>;
  }

• src/types.ts:197-199 (schema)

  TypeScript interface defining the output of create_node, containing the generated node ID.

  export interface CreateNodeResponse {
    nodeId: string;
  }