QUANDARYZ

counting the distinct screens a component can settle into when its responses arrive out of order.

A blotter whose rows and whose header exposure figure come from two endpoints settles into four different screens depending only on which response lands first, and every figure on every one of them was computed and sent by the server. One of them shows 41 position rows under a header reading 128 positions, with no spinner, no error and nothing stale in the sense anybody checks for. fast-check already explores the orderings; what this adds is the count, because knowing that an ordering exists which breaks a predicate is a different thing from knowing how many screens a user can be shown.

Tests

29

Node

24

Release

v0.1.0

Licence

MIT

The demo, as it really ran

$ npm run demo

A trader narrows the account filter from the whole book to one desk.
The rows come from one endpoint and the exposure figure in the header from another.

  guarded     1 distinct screen across 40 orderings
  unguarded   4 distinct screens across 40 orderings

  The guarded wiring applies the flag react.dev documents three times. It works.
  Without it, which screen the trader gets is decided by the network.

  One of them reads: 128 positions, 4.82m net
  above 41 rows. Both figures were computed and sent by the server, so there is no
  spinner, no error and nothing stale in the sense anybody checks for.
  Reproduce it with: ("all") then ("desk") then ("desk") then ("all")...

And a second property, on a screen that never tears at all:

  the risk panel settles the same way every time, and renders "Within limits"
  over a response about only the limits it asked about. No delivered value accounts
  for that phrase. It was composed in the browser out of the absence of a breach.

Output captured on 2026-08-29. It is committed to the repository and a test fails when it stops matching a live run, so this page cannot quietly drift from the code it describes.

Read it

• Source on GitHub the README carries the argument in full
• Release v0.1.0 changelog and tag

The rest of the toolset

• QUACKZ deflating a backtest that only looks good because it was picked out of two hundred
• QUOTEZ market data an agent can read and cannot act on
• QUELLZ measuring what prompt-injection containment costs in utility as well as in attack rate
• QUIDZ refusing the outbound payment that would have gone out twice
• QUESTZ stopping a scraper before it writes a CSV from a page that changed shape
• QUIZZ answering what a statistic said at the time, and refusing when it cannot
• QUARANTINEZ treating an outcome the venue never confirmed as terminal rather than as a retry
• QUENCHZ deciding in the open what a tool server gets free while it is still somebody's subprocess
• QUILTZ proving infrastructure code wrong without a cloud account, and saying what that cannot show
• QUAYZ telling a crash loop from an OOMKill, and naming the failure that no single field finds
• QUARRYZ keeping every version a statistical office published, and failing the build when it quietly issues another
• QUASHZ refusing a row whose outcome had not been decided yet when the decision would have been made
• QUALMZ a fixed number of looks at the holdout, where re-running the same configuration does not buy another
• QUEUEZ ordering a feed by its sequence, because on a real recorded session the clock goes backwards
• QUIETZ watching whether the data arrived rather than whether the server answered