selector_too_complex· code· HTTP 422· scope both· applies to service_call, deliveryResource selector or constraint exceeds parser hard limits defined in resource-selector-grammar.md §3.3 (string length, resources[] length, token count, nesting depth, single-field length, required_claims item count, constraint nesting). Dual-registered as a service code and a reason_code (see reason_codes[]) so it can be emitted as a top-level error and audit / abuse-detection can separate suspected parser-DoS attempts from ordinary format errors. See zh/authz/resource-selector-grammar.md §5.