struct

Checks core OpenAPI structure and field types before more focused rules run.

Attribute	Value
Category	Metadata
Maturity	Baseline
OpenAPI	Swagger 2.0; OpenAPI 3.0, 3.1, 3.2
Starter–Complete	Error

Intent

Catch malformed OpenAPI objects, invalid field types, unsupported properties, broken schema references, and invalid constraints early.

Flags

Structural violations such as missing version or required root fields, invalid schema type, non-array required or enum, negative size constraints, invalid path-item fields, malformed security definitions, and invalid discriminators or XML metadata. Exact checks vary by OpenAPI version.

Does not flag

Style and governance choices covered by focused rules. A structurally valid API can still fail other lint rules.

See it fail

openapi: 3.0.3
info:
  version: 1.0.0
paths: {}

Diagnostic: The field title must be present on this level.

Fix it

openapi: 3.0.3
info:
  title: Payments API
  version: 1.0.0
paths: {}

Minimal validation option

Set minimalOas3ValidationOnly: true to check only for an OpenAPI 3 version and a paths field. This deliberately skips all other struct checks.

profiles:
  default:
    rules:
      override:
        struct:
          severity: error
          options:
            minimalOas3ValidationOnly: true

Nearby: incomplete-spec, no-unresolved-refs.