operation-operationId-unique

Requires every nonblank operationId to be unique across the API document.

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

Intent

Generators and integrations use operationId as a unique key. Reuse can overwrite or merge unrelated operations.

Flags

Every occurrence after the first when two or more operations have the same nonblank ID. Comparison is exact and case-sensitive; callbacks and webhooks participate.

Does not flag

The first occurrence, unique IDs, and missing or blank IDs. Presence is handled by operation-operationId.

See it fail

paths:
  /payments:
    get:
      operationId: findPayment
      responses:
        '200': {description: OK}
  /refunds:
    get:
      operationId: findPayment
      responses:
        '200': {description: OK}

Diagnostic: Every operation must have a unique `operationId`.

Fix it

Give each operation a distinct stable ID:

/refunds:
  get:
    operationId: findRefund
    responses:
      '200': {description: OK}

Configure

profiles:
  default:
    rules:
      extends: [recommended]
      override:
        operation-operationId-unique: warn

Nearby: operation-operationId, operation-operationId-url-safe.