spec-querystring-parameters

Allows at most one in: querystring parameter per effective parameter set and forbids mixing it with in: query.

Attribute	Value
Category	Parameters
Maturity	Baseline
OpenAPI	OpenAPI 3.2 only
Starter–Complete	Error

See it fail

parameters:
  - in: querystring
    name: filter
    schema: { type: string }
  - in: query
    name: status
    schema: { type: string }

Fix it

Model the query string with one strategy: one querystring parameter or individual query parameters.

Path-level and operation-level parameters are evaluated together for each operation.

Nearby: query-param-collision, operation-parameters-unique.