Triggers

Triggers define how workflows start in ADK Studio. Every workflow begins with a Trigger node that determines the entry point — whether from user input, an HTTP webhook, a cron schedule, or an external event.

Trigger Types

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Manual Triggers

The default trigger type. When a workflow has a manual trigger, the chat input is shown with a configurable label and placeholder.

Configuration:

The input label appears above the chat input field, and the default prompt is used as placeholder text.

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Webhook Triggers

Expose an HTTP endpoint that starts the workflow when called. Useful for integrating with external services, CI/CD pipelines, or other applications.

Configuration:

Endpoints

Each webhook trigger creates two endpoints:

GET webhooks also work:

GET /api/projects/:id/webhook/my-path?message=Hello

Authentication

Bearer token:

curl -X POST "http://localhost:3000/api/projects/{id}/webhook/my-path" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"message": "Process this"}'

API key:

curl -X POST "http://localhost:3000/api/projects/{id}/webhook/my-path" \
  -H "X-API-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"message": "Process this"}'

Webhook Event Notifications

Subscribe to real-time webhook execution events via SSE:

GET /api/projects/:id/webhook-events

This stream emits events as webhooks are received and processed.

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Schedule Triggers

Run workflows on a recurring schedule using cron expressions.

Configuration:

Cron Syntax

Standard 5-field cron expressions:

┌───────────── minute (0-59)
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (0-6, Sun=0)
│ │ │ │ │
* * * * *

Examples:

The schedule service tracks last_executed timestamps to prevent duplicate runs.

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Event Triggers

Start workflows in response to external system events. Events are matched by source and eventType, with optional JSONPath filtering on the event data.

Configuration:

Sending Events

curl -X POST "http://localhost:3000/api/projects/{id}/events" \
  -H "Content-Type: application/json" \
  -d '{
    "source": "payment-service",
    "eventType": "payment.completed",
    "data": {
      "orderId": "12345",
      "amount": 99.00,
      "status": "active"
    }
  }'

JSONPath Filters

Filter events so the workflow only triggers when specific conditions are met:

Events that don't match the filter are silently ignored.

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Trigger-Aware Run Button

The Studio UI adapts based on the active trigger type:

• Manual — Standard chat input with the configured label and placeholder
• Webhook — Run button sends a simulated webhook payload
• Schedule — Run button sends the configured default prompt
• Event — Run button sends a simulated event payload

When a workflow has changed since the last build, the Send button transforms into a Build button to prompt recompilation.

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API Reference

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