Encyclopedia Evalica / Tracing and instrumentation / Span
Span
/span/A discrete unit of work within a trace, with a defined start and end time. Spans represent steps like LLM calls, vector database searches, tool invocations, or agent reasoning steps, and they nest to represent execution hierarchy. (noun)
“The LLM span took 4.2 seconds, dominating end-to-end latency.”
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