no-unknown

Id

@azure-tools/typespec-azure-core/no-unknown

Azure services must not have properties of type unknown.

Azure services must not have properties of type unknown. All properties should have well-defined types to ensure proper serialization and client SDK generation.

Impact

• Area: API, SDK

Allowing any JSON type makes the API and SDK unusable without extensive documentation.

❌ Incorrect

model Widget {
  name: unknown;
}

✅ Correct

Use a specific type:

model Widget {
  name: string;
}

Or use Record<string> for arbitrary key-value data:

model Widget {
  metadata: Record<string>;
}

Suppression

Treat like a type with no schema. Suppress only in the same cases you would accept additionalProperties; otherwise use a concrete type.