Codex runtime. Before using this skill, read ../executor-catalog/references/codex-runtime.md. It defines tool mappings, named-agent dispatch and stage-chat orchestration; use it for inherited Claude Code terms below.

TypeScript

The model knows TypeScript; these are the places where code an agent writes goes wrong anyway — they are what an
audit of a real project found. A rule a machine checks is one line here with its lint rule; the config is
repo-scaffold/references/quality-gates.md. Examples «так / не так»: references/examples.md.

The machine checks — keep them green, never disable one without a reason in the comment

The reviewer checks — the machine cannot

1. Every named error is its own type with a literal kind; an operation's expected failures are a union of
   them. Empty classes are identical to the compiler, so a missed branch passes as success — the audit's new
   error answered 204. A failure of an outside call keeps its cause and its operation. The lint checks the cause
   only for the classes listed in errorClassNames: a new error class made in a catch joins that list. A plain
   name there means the constructor takes the options object ({ cause }) second, as Error does — keep that
   shape (new InvalidCursor("shape", { cause: e })); a class that takes it elsewhere is listed as
   { name, argumentPosition } (1-based), or the lint reports correct code.
2. One translation of failures to answers, in one module, as a switch (e.kind) with assertNever — never
   a mapper per route. A table of codes is satisfies Record<ErrorKind, number>, so a new kind breaks the build.
3. A failure the user only sees as a generic answer writes one log line with the cause's name, never secrets,
   keys or addresses.
4. Impossible states are unrepresentable: {status: "loading"} | {status: "error", error} | {status: "ready", data}, not isLoading, error?, data? side by side.
5. Narrowing is real: by kind, in, typeof, or a type guard x is T whose body actually checks — a lying
   guard is worse than a cast.
6. Independent awaits run together (Promise.all); a sequence is a sequence only when one needs the other.
7. Ids of different things are different types (a brand or a value object): a user id is not an email — the
   audit found a creator matched by email on one side and by id on the other.
8. Domain values are readonly; a function does not change its arguments.
9. One rule, one module. A format, a status list, a length limit is imported from its owner — the domain
   model's «Кто ещё применяет» names it. A second regex or literal of the same rule is a finding even when it
   matches today: copies drift.
10. A shared step lives in a module of shared steps, never imported from another use case's file.

Python has the same rules in its own words: python.