Response Headers

Layer keeps turbopuffer-compatible read bodies in the upstream shape and returns Layer-specific metadata in response headers.

Header	Values	Returned by
x-layer-stable-as-of	Epoch milliseconds	Query, multi-query, scan counts
x-layer-next-cursor	Opaque cursor token	Single-query pagination
x-layer-warning	vector_attribute_dropped	Query, fetch
traceparent	W3C trace context	Query, multi-query

The watermark header can be absent before a stable observation exists.

SDKs expose these headers as fields where that is more convenient. For example, query_namespace returns upstream rows and also sets stable_as_of / next_cursor on the parsed response object when the headers are present.