value can now return "trace_fan_out"

What changed

Producer-side tools call this additive. It breaks exhaustive switches, strict parsers and generated client enums.

Affects this value on LLMObsCustomEvalConfigEvalScope reachable from 3 operations.

New value: trace_fan_out.

can now return "trace_fan_out"

Who is affected

Code that reads Datadog's LLMObsCustomEvalConfigEvalScope objects, used by 3 Datadog operations.

Before and after

Code that breaks

switch (response) {
  // existing branches …
  // no branch for "trace_fan_out"
  default:
    throw new Error("unexpected value");
}

Based on Datadog’s published API specification. How severity is decided.