Flow Studio
Three HIL Patterns
Three distinct interaction patterns cover the full range of human-in-the-loop requirements. Choose the pattern that matches the nature of the human interaction you need.
Pattern 1: Approval
The actor makes a binary decision: approve or reject. Optionally, they can add a comment to explain their reasoning.
| Aspect | Detail |
|---|---|
| Actor input | Decision: Approved | Rejected, plus optional Comment |
| Output ports | approved, rejected, timeout |
| Multi-actor | Supported via MultiPartyApprovalExecutor (Guide20) |
| Use cases | Budget approval, contract sign-off, policy exception, user access request |
| Node type | ApprovalNode |
Pattern 2: Form Input
The actor fills out a structured form with specific fields. The form is defined by an Atlas Form ID — the actor sees the form rendered in their task inbox and submits it. The submitted field values become the node's output.
| Aspect | Detail |
|---|---|
| Actor input | Any Atlas Form fields — text, numbers, dates, dropdowns, file uploads |
| Output ports | submitted, timeout |
| Multi-actor | Not supported — only single actor |
| Use cases | Data enrichment, manager input on employee info, address correction, risk assessment form |
| Node type | UserFormNode |
Pattern 3: Review
The actor reads presented content and acknowledges it. There is no approve/reject — just a required acknowledgement with an optional comment. Use when the workflow needs documented evidence that a specific person reviewed specific content.
| Aspect | Detail |
|---|---|
| Actor input | Acknowledgement (checkbox or click) + optional Comment |
| Output ports | acknowledged, timeout |
| Multi-actor | Not supported — single reviewer |
| Use cases | Policy acknowledgement, SLA review, generated report sign-off, AI output verification |
| Node type | ReviewNode |
Choosing the Right Pattern
| Question | Pattern |
|---|---|
| Does the actor need to approve or reject? | Approval |
| Does the actor need to fill in fields? | Form Input |
| Does the actor just need to confirm they saw something? | Review |
| Multiple people must all decide? | Approval (with All or Quorum strategy) |