# Session replay your coding agent can read

Session replays are video for people. Dataflare also turns every session into text, so a coding agent can read what happened, find the selector in your code and fix it.

## Turn it on

```html
<script defer src="https://glass.<you>.workers.dev/s.js" data-project="my-app"
  data-replay-sample-rate="0.1" data-replay-on-error-sample-rate="1"></script>
```

This records one session in ten, plus any session where an error happens (the recorder keeps a short buffer, so you see what led up to it). Every input is masked. Network requests are recorded as method, URL without its query string, status and timing; headers and bodies never are.

## What the transcript contains

```text
00:41 Clicked "Create account" (button)  #signup > button
00:41 Rage-clicked "Create account" (button) ×5
00:42 ERROR TypeError: crypto.randomUUID is not a function
      at submit (signup.js:88:14)
00:42 Request failed: POST /api/signup → 500 (210 ms)
```

Pages, clicks with labels and CSS selectors, rage clicks, dead clicks (a click after which nothing changed), errors with stack frames, failed and slow requests, and console errors. `replay_snapshot` describes what was on screen at any moment: headings, buttons and whether they were disabled, dialogs, masked form fields.

## Ask about it

- *"Find sessions where people started checkout and didn't finish, and tell me what went wrong."* The agent calls `list_replays` with `did_event` and `not_event`, then `summarise_replay` on the most frustrated ones.
- *"What's annoying users this week?"* `analyse_replays` groups the most rage-clicked elements, common errors and failing requests across sessions, with example links.

Findings can be pinned to a moment with `annotate_replay`, and show up on the player's timeline for people too.

## Where recordings live

In an R2 bucket in your Cloudflare account, gzipped, deleted after 30 days by default (`GLASS_REPLAY_RETENTION_DAYS`). See the [cost calculator](/pricing/) for what recording costs at your volume.