Outbound webhooks

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When to use this

• You want to get notified when an agent finishes a prompt instead of polling
• You are wiring Runtime into a Slack bot, Discord channel, or internal dashboard
• You want to trigger downstream actions (deploy, PR review, notification) when agents complete work

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Current webhook events

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Webhook payload

{
  "event": "prompt.completed",
  "session_id": "9f3a3f22-1d4e-4a9a-9a1f-3e5c6b1a0c11",
  "timestamp": "2026-05-09T15:18:54Z",
  "data": {
    "prompt_preview": "Add user authentication with JWT tokens",
    "model": "sonnet",
    "cost_usd": 0.07,
    "duration_seconds": 23,
    "status": "completed"
  }
}

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Configuring webhooks

• Timeout: 5 seconds per delivery attempt
• Retries: No automatic retries (fire-and-forget)
• Success: Any 2xx response is treated as successful delivery
• Failure: Non-2xx responses and timeouts are logged but not retried

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Consuming webhooks

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Minimal receiver

from flask import Flask, request

app = Flask(__name__)

@app.route("/webhooks/runtime", methods=["POST"])
def handle_webhook():
    event = request.json
    print(f"[{event['event']}] session={event['session_id']} "
          f"cost=${event['data'].get('cost_usd', 0):.4f}")
    return "", 200

import express from "express";
const app = express();
app.use(express.json());

app.post("/webhooks/runtime", (req, res) => {
  const event = req.body;
  console.log(
    `[${event.event}] session=${event.session_id} ` +
    `cost=$${event.data?.cost_usd?.toFixed(4) ?? "0"}`,
  );
  res.sendStatus(200);
});

app.listen(3000);

​

Posting to Slack

import httpx
from flask import Flask, request

SLACK_WEBHOOK_URL = "https://hooks.slack.com/services/T.../B.../xxx"

app = Flask(__name__)

@app.route("/webhooks/runtime", methods=["POST"])
def handle_webhook():
    event = request.json
    if event["event"] == "prompt.completed":
        text = (
            f"Agent finished in session `{event['session_id'][:8]}...`\n"
            f"*Prompt:* {event['data']['prompt_preview'][:100]}\n"
            f"*Cost:* ${event['data']['cost_usd']:.4f} · "
            f"*Duration:* {event['data']['duration_seconds']}s"
        )
        httpx.post(SLACK_WEBHOOK_URL, json={"text": text})
    return "", 200

​

Inbound triggers are a different thing

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Polling as an alternative

• Session status: GET /api/sessions/{id} - check last_prompt.status for completed, error, or timed_out
• Recent prompts: GET /sessions/telemetry/recent-prompts - see the latest prompts across all sessions
• Activity: GET /sessions/telemetry/activity - daily aggregate counts

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Next steps