In vLLM v0.23.0, `vllm:time_to_first_token_seconds` adds an observation when iteration processing identifies the request as prefilling/producing its first token.

MetricvLLM v0.23.0confidence: highverified 10 hr agoverified-code

PrometheusStatLoggerV1 metrics

vLLM v0.23.0 v1 metrics stats.py(vllm/v1/metrics/loggers.py:360-389)

definesprimarysource_codecode_introspection

Pinned release-tag semantics; do not carry to another version without continuity evidence.

In vLLM v0.23.0, vllm:time_to_first_token_seconds adds an observation when iteration processing identifies the request as prefilling/producing its first token.