General

The output_format enum on Lightning v3.1 (POST /waves/v1/lightning-v3.1/get_speech and /stream) is now correctly documented as ["pcm", "mp3", "wav", "ulaw", "alaw"]. The previously listed mulaw is rejected by the platform with an invalid_enum_value error and has been removed. Verified live against api.smallest.ai.

The sample_rate enum on the same endpoints now correctly includes 44100 (the model’s native rate) on both the SDK schema and the rendered API reference.

Internally, the base API specs at fern/apis/waves/{openapi,asyncapi}/* and the v4 docs override at fern/apis/waves-v4/overrides/* have been resynced — descriptions, error response shapes, and channel summaries that had drifted between the two layers are now identical. A new CI workflow (spec-drift-check) blocks any future PR that edits one layer without the other.

No customer-facing request shape, response field, or default value changes beyond the output_format/sample_rate corrections.