Flags inefficient database access — N+1 loops, unbounded reads, over-fetching —
in TypeScript/JavaScript as you type. Powered by the cardinal-core engine
(100% static: no LLM, no network, no database connection).
What it flags
- n-plus-one — a query awaited inside a loop or
.map/.forEach/.flatMap. - unbounded-read — a read with no filter and no limit (may scan the table).
- over-fetch — an unfiltered read on a large table with a selective alternative.
- order-by-rand —
ORDER BY RAND()/RANDOM()(full sort, no index). - leading-wildcard-like —
LIKE '%…'(non-sargable, full scan). - excessive-joins — a query joining many tables (counted by a real SQL parser).
Adapters: Prisma, Drizzle, Mongoose, and raw SQL (plus a heuristic fallback).
Business-logic context
Drop a cardinal.knowledge.yaml in your project (table sizes + filter
selectivity) and Cardinal becomes scale-aware — silencing provably-small loops,
escalating provably-large fan-out, and enabling over-fetch. The file is
discovered automatically and re-read live on change. Toggle via the
Cardinal › Use Knowledge setting.
Suppress a finding
On any Cardinal squiggle, open the lightbulb (⌘. / Ctrl+.) and choose
Suppress "" (Cardinal). You'll be asked for an optional reason, and —
when a cardinality fact is implied — offered the chance to record it. The
suppression is written to cardinal.knowledge.yaml, matched by rule + function +
normalized call text (not line number, so it survives edits above the call).
Usage
Install from the Extensions panel (search Cardinal), then open a
.ts/.js/.tsx/.jsx file. Problems appear as squiggles and in the Problems
panel, updating ~300ms after you stop typing.
Pairs with the cardinal-cli
command-line linter for CI gates, sharing the same engine and
cardinal.knowledge.yaml / cardinal.config files.