Unused schema component (OpenAPI 3.0)

Description

Defining a model in components.schemas does not by itself establish a request or response format. Connect needed schemas to their uses and clean up unnecessary models.

Potential impact

Unused models may remain in documentation or generated code, obscuring the actual data structures.

Remediation

Check use in requests, responses, parameters, and other models. Include indirect uses and references from external documents before removing unnecessary schemas.

Examples

These examples retain MyObject, used in the response body, and remove unused MyObject2.

Before

json

{
  "openapi": "3.0.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "operationId": "listVersionsv2",
        "summary": "List API versions",
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/MyObject"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "MyObject": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      },
      "MyObject2": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      }
    }
  }
}

After