docs/en/learn/human-in-the-loop.mdx
Human-in-the-Loop (HITL) is a powerful approach that combines artificial intelligence with human expertise to enhance decision-making and improve task outcomes. CrewAI provides multiple ways to implement HITL depending on your needs.
CrewAI offers two main approaches for implementing human-in-the-loop workflows:
| Approach | Best For | Integration | Version |
|---|---|---|---|
Flow-based (@human_feedback decorator) | Local development, console-based review, synchronous workflows | Human Feedback in Flows | 1.8.0+ |
| Webhook-based (Enterprise) | Production deployments, async workflows, external integrations (Slack, Teams, etc.) | This guide | - |
</Frame>
</Step>
<Step title="Provide Webhook URL">
When kicking off your crew, include a webhook URL for human input:
<Frame>
</Frame>
Example with Bearer authentication:
```bash
curl -X POST {BASE_URL}/kickoff \
-H "Authorization: Bearer YOUR_API_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"inputs": {
"topic": "AI Research"
},
"humanInputWebhook": {
"url": "https://your-webhook.com/hitl",
"authentication": {
"strategy": "bearer",
"token": "your-webhook-secret-token"
}
}
}'
```
Or with Basic authentication:
```bash
curl -X POST {BASE_URL}/kickoff \
-H "Authorization: Bearer YOUR_API_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"inputs": {
"topic": "AI Research"
},
"humanInputWebhook": {
"url": "https://your-webhook.com/hitl",
"authentication": {
"strategy": "basic",
"username": "your-username",
"password": "your-password"
}
}
}'
```
</Step>
<Step title="Receive Webhook Notification">
Once the crew completes the task requiring human input, you'll receive a webhook notification containing:
- Execution ID
- Task ID
- Task output
</Step>
<Step title="Review Task Output">
The system will pause in the `Pending Human Input` state. Review the task output carefully.
</Step>
<Step title="Submit Human Feedback">
Call the resume endpoint of your crew with the following information:
<Frame>
</Frame>
<Warning>
**Critical: Webhook URLs Must Be Provided Again**:
You **must** provide the same webhook URLs (`taskWebhookUrl`, `stepWebhookUrl`, `crewWebhookUrl`) in the resume call that you used in the kickoff call. Webhook configurations are **NOT** automatically carried over from kickoff - they must be explicitly included in the resume request to continue receiving notifications for task completion, agent steps, and crew completion.
</Warning>
Example resume call with webhooks:
```bash
curl -X POST {BASE_URL}/resume \
-H "Authorization: Bearer YOUR_API_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"execution_id": "abcd1234-5678-90ef-ghij-klmnopqrstuv",
"task_id": "research_task",
"human_feedback": "Great work! Please add more details.",
"is_approve": true,
"taskWebhookUrl": "https://your-server.com/webhooks/task",
"stepWebhookUrl": "https://your-server.com/webhooks/step",
"crewWebhookUrl": "https://your-server.com/webhooks/crew"
}'
```
<Warning>
**Feedback Impact on Task Execution**:
It's crucial to exercise care when providing feedback, as the entire feedback content will be incorporated as additional context for further task executions.
</Warning>
This means:
- All information in your feedback becomes part of the task's context.
- Irrelevant details may negatively influence it.
- Concise, relevant feedback helps maintain task focus and efficiency.
- Always review your feedback carefully before submission to ensure it contains only pertinent information that will positively guide the task's execution.
</Step>
<Step title="Handle Negative Feedback">
If you provide negative feedback:
- The crew will retry the task with added context from your feedback.
- You'll receive another webhook notification for further review.
- Repeat steps 4-6 until satisfied.
</Step>
<Step title="Execution Continuation">
When you submit positive feedback, the execution will proceed to the next steps.
</Step>
HITL workflows are particularly valuable for: