Human Approval for n8n AI Agent Workflows

#ai #tutorial #opensource #llm

Add human approval for n8n AI Agent workflows using Impri's REST API in stock HTTP Request and Wait nodes — no custom node, no code beyond one small Function block.

Where the gate goes in the workflow

A typical setup: a Zendesk Trigger node fires on a new ticket, an AI Agent node (backed by whatever model you've wired into n8n) drafts a reply, and a final node would normally post that reply straight back to the customer. That last step is the one worth gating — everything upstream is just reasoning, nothing has left the building yet.

The fix isn't a second AI Agent node double-checking the first one's work. It's an external decision the workflow cannot proceed without: Impri holds the draft, a human taps approve or reject, and only the approved branch reaches the node that actually calls the Zendesk API.

The node pattern

Five nodes cover the whole loop:

Node	Purpose
Code (JavaScript)	Builds the `POST /v1/actions` body from the AI Agent's output
HTTP Request	`POST /v1/actions` — pushes the draft, returns `id` and `inbox_url`
Wait	Pauses 10s before each poll
HTTP Request	`GET /v1/actions/:id` — checks status
IF	Branches on `status`: loop back to Wait if `pending`, continue if not

Set Authorization: Bearer im_<key> once as an n8n Header Auth credential and reuse it on both HTTP Request nodes. A key scoped to actions only is enough — this workflow never needs admin.

Building the request in a Code node

// Code node, right after the AI Agent node
const ticket = $('Zendesk Trigger').item.json;
const draft = $input.item.json.output; // AI Agent node's text output

return {
  json: {
    kind: "zendesk.reply",
    title: `Reply: ${ticket.subject}`,
    preview: {
      format: "markdown",
      body: draft,
    },
    target_url: `https://yourcompany.zendesk.com/agent/tickets/${ticket.id}`,
    expires_in: 3600,
    editable: ["preview.body"],
  },
};

Point the next node's HTTP Request body at {{ $json }} from this Code node — no manual JSON-building in the HTTP node itself.

The polling loop, n8n-style

n8n has no built-in "poll until done" node, so you build the loop with a back-edge: Wait (10s) → HTTP Request (GET status) → IF {{ $json.status === "pending" }} → true branch connects back to the Wait node, false branch continues downstream. This is the same shape as docs/integrations.md's n8n section, just spelled out node-by-node.

For a support-ticket workflow, keep expires_in short (an hour, as above) — a canned reply that's a day late has usually been overtaken by a human agent replying directly in Zendesk anyway.

Reading the decision

Once the IF node's false branch fires, the last GET response carries the decision:

{
  "status": "approved",
  "decision": {
    "verdict": "approve",
    "final_preview": { "format": "markdown", "body": "Edited reply text..." },
    "diff": "- original line\n+ edited line"
  }
}

Route on status: only the approved path reaches the Zendesk "post reply" node, and it must read decision.final_preview.body, never the Code node's original draft — the reviewer may have tightened the wording before approving.

Skipping the loop with a webhook

Polling every 10 seconds is fine for low-volume ticket queues, but if your n8n instance has a public URL, set callback_url in the Code node's JSON to an n8n Webhook node's URL instead. Impri POSTs the decision there the moment a human decides, and you can replace the whole Wait/GET/IF loop with a single Webhook trigger that starts a second workflow. Signature verification for that payload is documented in webhooks.md.

What this doesn't replace

Impri is the approval gate, not the workflow engine — n8n still owns branching, retries, and scheduling. Impri doesn't read the ticket or judge whether the reply is good; it shows the draft to a human and records what they decided. And the gate only holds if the Zendesk API credential lives on the "post reply" node and nowhere else in the workflow — if an earlier node also holds that credential, the AI Agent's output could reach Zendesk through a path that never touches Impri at all.

Next step

Start from Quickstart to get a key and push your first action, or see the accurate n8n reference pattern in Integrations.

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