Webhooks: Trigger Your Agents from GitHub, Slack, and Anywhere

Agents That React to the World

Until today, running an agent meant opening a thread and typing a prompt — or scheduling a task for later. Both patterns start with you.

Webhooks flip that. Now external events can start agent tasks automatically. A push to main, a new Slack message, a payment callback, a form submission — anything that can send an HTTP request can trigger your agent.

No polling loops. No cron schedules checking for changes. The event happens, your agent starts working, and you get notified when it's done.

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How It Works

Every webhook trigger you create gets a unique URL and a signing secret. Point your service at the URL, and Computer Agents handles the rest.

The flow:

1. An event occurs in an external service (e.g. a GitHub push)
2. The service sends a POST request to your webhook URL
3. Computer Agents verifies the HMAC signature
4. Your agent starts a new thread and executes the configured action
5. Results appear in your threads — with full context of what triggered them

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Setting Up a Webhook

Head to Settings > Webhooks and click New Webhook. You'll configure:

• Source — GitHub, Slack, or Custom Webhook. Each source comes with a setup guide that walks you through the integration step by step.
• Event — The specific event to listen for. For GitHub, you get a dropdown of common events like push, pull_request, and issues. For other sources, you define the event name yourself.
• Environment — Which cloud environment the agent should run in.
• Agent — Optionally pick a specific agent (otherwise the default is used).
• Action — Either a static message ("Run the test suite") or a template that injects the event payload so the agent can react to the actual data.

Once created, you'll see your Webhook URL and Webhook Secret — copy them into your service's webhook settings, and you're live.

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Static Messages vs. Templates

You have two options for what the agent receives when a webhook fires:

Static message — The same instruction every time. Good for simple automations:

"Run the test suite and report any failures."

Template with payload — The webhook payload gets injected into your message via {{payload}}. This lets the agent see and react to the actual event:

"A new push just landed. Review the following commits and flag anything that looks risky: {{payload}}"

Templates are powerful because they turn your agent from a button-presser into a context-aware responder. It doesn't just "run tests" — it reviews the specific commits that were just pushed, triages the specific issue that was just opened, or responds to the specific message that was just sent.

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Example: CI Agent on Every Push

Here's a practical setup for running an agent on every push to your main branch:

1. Create a webhook in Settings > Webhooks
   • Source: GitHub
   • Event: push
   • Environment: your CI environment (with Node.js, test tools, etc.)
   • Action (template): A push was made to the repository. Pull the latest changes, run the full test suite, and report the results. Here's the push payload: {{payload}}
   • Filter: branch main
2. Copy the Webhook URL and Secret
3. In GitHub: go to your repo > Settings > Webhooks > Add webhook
   • Payload URL: paste your webhook URL
   • Content type: application/json
   • Secret: paste your webhook secret
   • Events: select "Just the push event"

Every push to main now triggers your agent. It pulls, tests, and reports — and you see the results in your threads.

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Example: Slack Responder

Set up an agent that reacts to Slack messages in a specific channel:

1. Create a webhook with source: Slack, event: message
2. In your Slack app settings, add the webhook URL as an Event Subscription
3. Action (template): You received a Slack message. Read it and respond helpfully: {{payload}}

Your agent now acts as a channel participant — reading messages and responding with context from its environment.

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Signature Verification

Every webhook request is verified using HMAC-SHA256. When you create a trigger, a unique secret is generated. The sending service signs the request body with this secret, and Computer Agents verifies the signature before processing.

This means:

• No unauthorized triggers — only requests signed with your secret are accepted
• Tamper-proof payloads — the signature covers the entire request body
• GitHub and Slack native — both services support HMAC signing out of the box

For custom integrations, compute the HMAC-SHA256 of the JSON body using your webhook secret and pass it in the X-Webhook-Signature header.

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Managing Your Webhooks

From the Webhooks settings page, you can:

• Enable / Disable triggers without deleting them — useful for maintenance windows
• Test fire a trigger to verify the end-to-end flow before going live
• View setup instructions specific to each source (GitHub, Slack, custom)
• Delete triggers you no longer need

Each trigger shows when it was last fired, so you can tell at a glance which webhooks are active and which might need attention.

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What You Can Build

Webhooks open up a class of automations that wasn't possible before:

• CI/CD agents that run tests, check for security vulnerabilities, or deploy on every push
• Issue triagers that label, assign, and respond to new GitHub issues
• PR reviewers that read diffs and leave review comments automatically
• Slack assistants that respond to questions in specific channels
• Monitoring agents that react to alerts from Datadog, PagerDuty, or custom systems
• Form processors that analyze submissions from Typeform, Tally, or your own backend

If it can send an HTTP POST, it can trigger your agent.

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Get Started

Webhooks are available now for all users. Head to Settings > Webhooks to create your first trigger, or check the API documentation to manage triggers programmatically.