The playground

See an agent say 1 row while 301 changed, block it, and undo it, in your browser.

Before you start

• A browser with DecompressionStream (Safari 16.4 or later, current Chrome, Edge or Firefox). Nothing to install, no account.

Open it

Go to deedglass.com/play. Everything runs in the tab: Postgres (PGlite) with the demo’s Acme Store schema and trigger, and the rules engine (cel-js). Both are served from deedglass.com, and the page makes no third-party requests.

The three scenes

1. A blocked DROP. The agent sends DROP TABLE public.orders. The rules refuse it before Postgres sees it: ✕ Blocked by policy "block-destructive-sql", and all 500 rows stay as they were.
2. 1 row reported, 301 changed. The agent ships order 42 and reports one row. A trigger on the table ships 300 more. The check says ✕ Doesn't match · said 1 row · changed 301 and names the trigger. Press Undo and all 301 rows go back: ✓ 301 rows restored.
3. Edit the policy, then approve. Change the 6-line policy so writes wait for a person and run the scene again. It waits (◐ Waiting for you to approve); approve it, then undo it.

Check the records

Every step is sealed as a record in the tab. Check these deeds runs the same offline check as /verify. Change one byte and the check fails.

Share this scene appears after a scene has run. The link holds the scene and your policy in the part after #, which never reaches a server.

Next: scan your own setup

npx deedglass scan

What it doesn’t do

• The playground compares table snapshots in your browser. Deedglass itself reads Postgres’s own change log.
• Its rules engine is cel-js running rules exported from the Go engine; the two agree on all 40 test cases in the parity suite.
• Nothing you do there reaches a server. Close the tab and it’s gone.