tl;dr: Cloudflare's Quick Tunnels (`cloudflared tunnel --url http://localhost:8000`) expose a local server to the internet via an ephemeral HTTPS URL on Cloudflare's edge, with no account, DNS, or open inbound ports required. The feature now emits structured JSON (hostname, edge, health) to stdout, making it easier for coding agents and scripts to consume without parsing logs. Tunnels are ephemeral—dying with the process—and useful for webhooks, previews, and agent eval loops.