n8n-workflow-tester-safe

Instructions

Implementation Reference

• src/index.ts:246-256 (handler)

  MCP request handler for 'connect_nodes' tool - validates input parameters using Zod schema and calls the connectNodes function

  if (name === 'connect_nodes') {
    const { workflowId, source, target, sourceIndex, targetIndex } = z.object({
      workflowId: z.string(),
      source: z.string(),
      target: z.string(),
      sourceIndex: z.number().optional(),
      targetIndex: z.number().optional(),
    }).parse(args);
    const updated = await connectNodes(workflowId, source, target, sourceIndex ?? 0, targetIndex ?? 0);
    return { content: [{ type: 'text', text: JSON.stringify(updated, null, 2) }] };
  }

• src/n8n-client.ts:137-149 (handler)

  Core implementation of connectNodes - fetches workflow, manages connections array structure, adds new connection between source and target nodes, and updates the workflow via n8n API

  export async function connectNodes(workflowId: string, source: string, target: string, sourceIndex = 0, targetIndex = 0) {
    const workflow = await getWorkflow(workflowId);
    const connections = workflow.connections && typeof workflow.connections === 'object' ? workflow.connections : {};
    const existing = (connections[source] && connections[source].main) ? connections[source].main : [];
    const next = [...existing];
    while (next.length <= sourceIndex) next.push([]);
    next[sourceIndex] = [
      ...(Array.isArray(next[sourceIndex]) ? next[sourceIndex] : []),
      { node: target, type: 'main', index: targetIndex },
    ];
    workflow.connections = { ...connections, [source]: { main: next } };
    return await updateWorkflow(workflowId, workflow);
  }

• src/index.ts:85-99 (registration)

  Tool registration defining the 'connect_nodes' tool metadata and input schema with workflowId, source, target (required) and sourceIndex, targetIndex (optional) parameters

  {
    name: 'connect_nodes',
    description: 'Create a main connection between two nodes in an existing workflow.',
    inputSchema: {
      type: 'object',
      properties: {
        workflowId: { type: 'string' },
        source: { type: 'string' },
        target: { type: 'string' },
        sourceIndex: { type: 'number' },
        targetIndex: { type: 'number' }
      },
      required: ['workflowId', 'source', 'target'],
    },
  },