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Glossary and References

This appendix separates terms used by OpenTelemetry, application architecture, evaluation systems, and observability backends. Similar words do not always represent the same data model.

Glossary

TermMeaning in this series
AgentSoftware that uses a model to select or sequence actions toward a task.
AttributeTyped key-value metadata attached to a span, resource, log, or metric point.
BaggageApplication key-value context propagated across boundaries; not a telemetry record.
ConversationA set of related user and agent interactions, usually correlated by gen_ai.conversation.id.
EvaluationA versioned judgment against an explicit criterion, produced by code, a human, or a model.
EventA timestamped occurrence; in tracing, a span event belongs to one span.
ExemplarA link from an aggregated metric observation to a representative trace.
GuardrailA control that detects, transforms, blocks, or escalates an input, output, or action.
Instrumentation scopeIdentity and version of the component that emitted telemetry.
LinkA causal or correlational relationship between a span and another span context that is not its parent.
LogA timestamped record that can carry severity, body, attributes, trace ID, and span ID.
MetricAn aggregated measurement over time and a bounded set of dimensions.
ObservationLangfuse object for an operation inside a trace; it can represent several observation types.
OTLPOpenTelemetry Protocol for exporting traces, metrics, and logs.
ResourceAttributes describing the entity that produced telemetry, such as a service.
Root spanA span without a parent in its trace.
SamplingSelection of telemetry for recording or export; not a privacy mechanism.
SessionBackend or application grouping for related interactions. It is not an OpenTelemetry parent of a trace.
SpanA timed operation with context, attributes, events, links, status, and parent relationship.
SLIA quantitative indicator of service behavior.
SLOA target for an SLI over a defined population and time window.
TaskA business unit of work that can span requests, traces, workers, or conversation turns.
TraceA graph of causally related spans that share a trace ID.
Trace contextIdentifiers and flags propagated so spans can join a trace.

OpenTelemetry

The GenAI conventions are under active development. Check the linked repository and schema version before implementing or upgrading attributes.

OpenAI

LangGraph and Langfuse

Security, privacy, and risk

Evaluation and operations