In vLLM v0.23.0, vllm:request_time_per_output_token_seconds declares 19 literal histogram bucket boundaries in its registration, from 0.01 to 80.0.

Metric

Applies when

Evidence

Does not establish

• whether these boundaries suit any particular workload
• the distribution of observed values

Guards

• vllm_version = v0.23.0
• metric_name = vllm:request_time_per_output_token_seconds

Freshness

Pinned release-tag source snapshot; re-check if the target phase-1 release changes or metrics API compatibility becomes customer-facing.