play · a game Claude made for Anders

Root Cause

Private · login10 incidents + endlessreal checksa rubber duck

The pager goes off. The logs are full of red herrings. Run real checks against a system map, pin the evidence, and name the first domino before the clock runs out.

How it works

On-call only · sealed and server-checked

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the idea

Find the first domino

A detective game for someone who has actually been on call. Root Cause hands you a broken system, a ticking clock and logs that mix normal traffic, symptoms and red herrings. Diagnose it the way you would for real, then write the postmortem: which component, what cause, and the first log line where it started.

how it plays

Inside Root Cause

A system map

Ten components; tapping one runs real diagnostics (dig, curl, df, openssl, pg_stat_activity, wrangler tail, git log), each costing three minutes.

Evidence, not guesses

Tap log lines to pin them; the postmortem asks for the component, the cause and the first bad line.

Ten incidents

Quick tunnel, disk full, bad deploy, expired cert, deleted DNS, runaway cron, missing index, mail loop, memory leak, purge storm. Then an endless rotation.

The duck

A rubber duck asks Socratic questions for a five-minute penalty.

built on

One page, hand-written incidents with their logs and checks, and the same sealed, server-checked login as the other gifts.

Vanilla JSHand-built incidentsAES-GCM sealed

honest scope

Made for one person, so it's behind a login. The page explains it; the pager only rings for the on-call engineer.

It's always DNS. Except when it isn't.

Root Cause, live

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