Presets

Built-in rule sets. Name one, or one of its topics, in the config’s presets or with --preset:

Preset	Rules	For	What it asks for
typescript	11	any TypeScript project	Data from outside checked at runtime, invalid states unrepresentable, errors never swallowed, resources released on every path, arguments not mutated, and tests that assert outcomes and stand alone.
react	10	components and hooks	Logic for an event in its handler rather than an effect, effects that clean up and ignore stale fetches, useSyncExternalStore for outside stores, state that neither copies props nor contradicts itself, and Server Functions and Server Components that guard what crosses to the client.
security	4	any project	Secrets kept out of logs, error messages, and responses; parameterized SQL; no untrusted input in shell commands, eval, or file paths; and secrets compared in constant time. From OWASP’s cheat sheets.
effect	16	code written with Effect	Steps sequenced with Effect.gen, instrumentation attached with .pipe, config read through a service and validated, secrets redacted, branded primitives and tagged unions, defects kept apart from typed errors, services built by layers, and tests with their own layers and TestClock.
alchemy	41	code that deploys with alchemy	Where Config and bindings are read, which resources keep their data, how secrets stay out of bundles and logs, authorization on public URLs, migrations, durable workflows, and custom providers.

• Name presets in the config’s presets, or on the command line with --preset, repeated or separated by commas, as in --preset effect,alchemy. Naming presets on the command line makes the config file optional, and presets named in both places apply together.
• A topic, one of a preset’s subdirectories, is a preset of its own: --preset effect/basics applies only the rules under presets/effect/basics/, and alchemy/secrets applies only alchemy’s secrets rules. security has no topics.
• To change a preset’s rule without copying it, use Overrides.
• presets/README.md lists every rule in each preset, with a one-line summary and a link to the full rule.

What every preset does

• It has no rules for what a linter checks exactly. presets/README.md names the lint rules to turn on instead.
• A preset rule says “must” only where its source makes a requirement, and “should” where the source gives advice.
• A topic’s rules keep the ids they have in the whole preset, so a topic and its preset share cached judgments, and naming both applies each rule once.
• effect and alchemy have no rule that typescript or security already has, so a project on Effect or alchemy names typescript and security too.