Read-only Effect methods

Set readOnly on a method; handlers must remain ordinary Effects and must not mutate state or perform writes.

value: method({ input: {}, success: Schema.Number, readOnly: true })
cached: method({
  input: {},
  success: Schema.String,
  readOnly: { cache: { ttlNanos: 5_000_000_000n } },
})

Whether a read-only result is cached per principal is derived from its input: declare a PrincipalSchema parameter when the response depends on the caller. A read-only handler without that declared parameter cannot access the ambient Principal service. Do not mark a method read-only merely because its return type is immutable.