Human-in-the-Loop Design Pattern
The Human-in-the-Loop pattern integrates human review and approval into agent workflows — ensuring that high-stakes, ambiguous, or irreversible actions are reviewed by a human before execution.
What Is Human-in-the-Loop?
The Human-in-the-Loop (HITL) pattern integrates human review and approval into agent workflows at defined checkpoints. The agent pauses, presents its proposed action or output to a human reviewer, and proceeds (or redirects) based on the human's decision. It is the primary mechanism for maintaining human control over consequential agent actions.
When to Use It
- Irreversible actions (data deletion, external communications, financial commitments above threshold)
- Ambiguous situations where the agent's confidence is low
- Compliance-required approvals (expense approval, access grants, contract execution)
- Novel situations the agent hasn't encountered before
When NOT to Use It
- Routine, low-risk actions with high confidence — HITL on every action defeats the purpose of automation
- Time-sensitive actions where the approval latency would be harmful
- When you have already validated the action through pre-execution checks
Designing Effective Approval Requests
An approval request that doesn't give the reviewer enough information to make a confident decision results in rubber-stamping — every request gets approved because rejection requires effort. Design approval requests to include: what the agent is proposing to do, why it is proposing it (the reasoning), the specific data involved, and the consequences of approval vs. rejection.