Traces

Documentation Index

Fetch the complete documentation index at: https://docs.foglamp.dev/llms.txt

Use this file to discover all available pages before exploring further.

A trace is one top-level generateText / streamText call. The Traces view lists them; opening one shows the full execution as a waterfall you can inspect span by span and replay in real time. See the data model for how traces and spans are defined.

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Traces list

A paginated table (newest first) over the selected date range. Columns: trace id, name (traceName, falling back to agentName, else —), span count, tokens, duration, cost, and when it ran. Errored traces carry a red badge. Click a row to open the trace.

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Waterfall

Each span is a row, indented by its parent (parentSpanId) so nested tool calls and steps sit under their parent. Span types are colour-coded: The bar’s offset and width are proportional to when the span started and how long it ran, so you can see serial vs. overlapping work at a glance.

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Span detail

Click any span to open its detail panel:

• Timing — start time, duration, and TTFT (time to first token).
• Model — provider and model id.
• Tokens & cost — input/output tokens, computed cost, and the pricing source that produced it (resolved price vs. a custom rule).
• Throughput — for streaming LLM spans, a tokens/second headline.
• Payloads — the captured input and output, pretty-printed and collapsible (subject to recordInputs/recordOutputs).
• Errors & metadata — the error message (if any) and any span metadata.

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Scores

If a trace has been scored by an eval, a Scores card lists each result as a badge — green for pass, red for fail, or the numeric score. Hover a badge to read the judge’s reason.

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Replay

The Replay card plays the trace back on its real timeline: press play, scrub with the slider, and switch between 1× / 2× / 4× speed. As it plays, the readout shows the currently streaming span, its token count, and instantaneous tokens/second; the TTFT moment is marked on each LLM bar. Replay is powered by the intra-stream token samples the SDK records — no extra instrumentation needed. Opening a trace with ?replay=1 auto-plays it.