Human approval¶

A Human node pauses the run in status waiting and asks its prompt. The answer goes to the node's output_field, so a Condition after it can branch on it.

Answer in the studio¶

The logs in the Run tab show the question with Approve (approved), Reject (rejected), or a free-text Send response. Only the run's owner can open, answer or cancel the run here.

The Approvals page¶

Approvals (/approvals, the person icon in the header) lists every step waiting for you, across all workflows: runs you own, and runs where you are an approver of the waiting Human node. Each row shows the workflow, the step, the question, who started the run, how long it has waited and the channel the request went to. Answer with Approve, Reject or a text reply, right in the row.

• Name approvers by e-mail in the Human node's Approvers field. It works with or without an approval channel. Each address must belong to a studio account.
• An approver sees only the request: not the workflow, the run trace or its data. Open run shows only for the run's owner, and for the workflow's owner or an admin.
• The first answer wins, wherever it comes from: the editor, the Approvals page or a chat button. Later answers are refused. An answer here closes the chat request and edits its message.
• The header badge counts the steps waiting for you, and Workflows shows a link to the page while any are waiting.

Checkpoints live in the database, so a restart resumes the run where it stopped. Waiting time does not count toward the run's duration. A wait longer than STUDIO_WAIT_TTL seconds (default 7 days; 0 never expires) becomes expired, and resuming then returns 410 RUN_EXPIRED.

GET  /api/approvals/inbox                       # steps waiting for you, owner or approver
POST /api/approvals/inbox/{run_id}  {"response": "approved"}
GET  /api/runs/pending                          # your own waiting runs
WS   /ws/run   {"resume_run_id": "…", "response": "approved"}
POST /api/runs/{id}/cancel

Deadlines¶

A Human node can have a Deadline (the switch under the approval channel). Without one, the step waits until someone answers or until STUDIO_WAIT_TTL.

• A reminder goes to the run owner and the approvers as a notification (the bell, and e-mail if they turned it on). On a node with an approval channel it is also a new message with new buttons; the old message says a reminder was sent, and its buttons stop working.
• Reject and Approve on timeout follow the node's normal branches. The run trace (run_resumed, by: {"channel": "deadline"}) and the Audit log (Timed out) say the deadline answered, not a person.
• Hand to other approvers happens once. The listed people become approvers, get the request in their channel and on their Approvals page, and have the same time again. If nobody answers then, the step is rejected. Addresses with no studio account are skipped and logged.
• Chat buttons expire at the deadline when it comes first.
• The deadline must be shorter than STUDIO_WAIT_TTL (twice the time with a hand-over); the validator says so otherwise.
• The Approvals page shows the due time of each step, or Overdue, with the nearest deadline first.

Durations are wall-clock time, with no business hours. Deadlines fire from the worker's maintenance loop, once each, also with several workers and after a restart. A deadline that passed while the server was down fires right after it starts.

Notifications¶

The bell lists unread notifications and receives them live on /ws/notifications, with a 30 s poll as fallback. Each user picks what they receive under Settings → Profile.

Approve from chat¶

A Human node can also send the request to an approval channel:

The same rules apply everywhere: only the run owner or an approver listed on the node, one answer, and an expiry (STUDIO_APPROVAL_TTL, default 86400 s). Button tokens are HMAC-signed and single-use. Messages follow the run owner's language. Answering in the studio disables the chat buttons; cancel and expiry close the request. With no channel configured, nothing is sent.

Setting up each channel is in Approval channels.

Approvals from an Agent node¶

An Agent node can ask before it calls a tool marked Needs approval. The run waits exactly as at a Human node: the step, named Agent › tool, shows the tool and its arguments, and it goes to the run panel, the Approvals page and the approval channel set on the Agent node, with its approvers and deadline. Approve runs the call. Reject, or a text reply, rejects it, and the model is told so, with the text as the reason. Each call asks again.

AI review¶

A model can review a request before people see it: as a suggestion shown next to the request, or approving on its own when it is sure. See AI review of approvals.

Approvals inside a called workflow¶

When an Agent node calls another workflow as a tool (see Workflows as tools), a Human node or a tool approval inside that workflow asks as usual. The request names both workflows, for example Support team › Refund desk, on the Approvals page and in the channel message. The calling run waits too, but it is not listed: it goes on by itself once the called run ends.

A typical pattern¶

Start → LLM (draft a reply) → Human (approve the draft?) → Condition on decision
      ├─ approved → Send email → End
      └─ rejected → End

The Approval flow starter template has this shape.