new·The score now tells you which way it movedA brain's exam only ever grows: its own material writes questions, and so does every question a real caller asked and did not get answered. The score is a percentage over that growing set, so a brain that learned more could post a smaller number — and this week three did. One of them answered two MORE questions than the week before and showed eighteen points less. Printed as a single percentage, that reads as decline to a reader and as punishment to anyone who contributes material.all news →
mozg.beta
Sign in

explore / Web & frontend / mozg / TanStack Query

TanStack Query · React

Answer questions about using TanStack Query in React: the guides for queries, mutations, invalidation, caching behaviour, suspense, infinite queries, optimistic updates, SSR and hydration, testing, and the migration from v4.

833 notes · updated 2026-08-14 · trained 89%

since last sitting: +30 newly passed — this brain is learning · the verified changelog →

use this brain
# sign in to get a token
$ claude mcp add --transport http mozg \
https://mozg.sh/mcp --header "Authorization: Bearer …"
> use mozg/tanstack-query-react — …
Sign in — get this command with your token in it

New here? Sign in and this exact command appears with your token already inside — copy, paste into your terminal, done.

Or just add it

Sign in and add it, and every agent you have connected can read it — nothing to download, and it stays current as the author updates it.

Sign in to add it

Ask it things like

answers 29/32 on its latest exam · anti-bluff 1/1
What is the default `gcTime` value, and what does it represent?Caching & Garbage Collection
What is the `initialPageParam` and why is it required for infinite queries?Infinite Queries
What major breaking change happened with query and mutation callback hooks in v5?Migration from v4
What is the recommended pattern for implementing optimistic updates using the cache?Optimistic Updates
If I call `invalidateQueries`, what happens to the query immediately, and what happens next?Query Invalidation
What are the three steps in the hydration process for server-side rendering with React Query?SSR & Hydration
What does the `isPaused` return value indicate, and when would it be true?Core Query Usage
If I want to be notified only when specific fields change rather than all query state changes, what parameter should I use?Core Query Usage

What it can answer

32 coverage checks
89%
Answers 30 of the exam's 33 questionsIt answers 30 questions, 30 more than last time, out of an exam that grew by 33.Nothing it used to answer has stopped working.
Core Query Usage3 / 3
Infinite Queries3 / 3
Migration from v43 / 3
SSR & Hydration3 / 3
Advanced Features2 / 2
Mutations2 / 2
Optimistic Updates2 / 2
Query Invalidation2 / 2
Suspense Mode2 / 3
Testing2 / 2
TypeScript2 / 2
Caching & Garbage Collection1 / 2
Devtools1 / 1
Network Mode1 / 2
exam badge — share this score →

Attacks survived

re-run weekly · 2026-08-10
gate-battery12/12 known hostile payloads caught by the ingest gate
injection-corpusevery active note scanned — no steering language
secret-corpusevery active note scanned — no keys or credentials

heuristic scans against known attack classes — measured and dated, not a promise of unpoisonability

Inside

  • TanStack Query and global state managers · out of scope
  • useQuery return values and state properties · core query usage
  • isFetchedAfterMount return value · core query usage
  • isFetching return value · core query usage
  • isEnabled return value · core query usage
  • isRefetching return value · core query usage
  • isLoading return value · core query usage
  • isPlaceholderData return value · core query usage
  • isFetched return value · core query usage
  • fetchStatus return value · core query usage
  • isStale return value · core query usage
  • isPaused return value · core query usage
  • useQuery hook signature and parameters · core query usage
  • isInitialLoading return value deprecated · core query usage

Licence

CC BY-NC-SA 4.0

Use it, copy it, build on it, with credit. Selling it is not allowed.