Catch the Cat

A tiny Cloudflare Worker demo app for Mistle webhook flows. The game is intentionally simple: catch the cat head, watch it speed up, and use the deterministic fault control when you need an error event for Sentry.

Tooling

This project uses mise to pin Node and pnpm:

mise install
mise exec -- pnpm install

Development

mise exec -- pnpm dev

Deploy

CLOUDFLARE_ACCOUNT_ID=<account-id> mise exec -- pnpm deploy

Sentry

Create a Sentry JavaScript project and add its DSN as a Cloudflare Worker secret:

mise exec -- pnpm exec wrangler secret put SENTRY_DSN

Then redeploy:

CLOUDFLARE_ACCOUNT_ID=<account-id> mise exec -- pnpm deploy

Deterministic Error

The Worker throws a stable error when this URL is requested:

/api/demo-error?code=mistle-demo

The in-app ! and Fault controls call that endpoint and then throw a stable browser error:

MISTLE_DEMO_WORKER_ERROR: deterministic cat fault
MISTLE_DEMO_CLIENT_ERROR: deterministic cat fault

Those two fixed error messages are intended for a later Sentry setup, where Mistle can receive Sentry webhooks and fan the issue out to Linear, Slack, and an agent session.