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Sessions

Get project session

Returns a single session by id, including its conversation: the system instructions and the messages of the session's latest LLM completion, in OpenTelemetry GenAI format.

get/v1/projects/{projectSlug}/sessions/{sessionId}

Path parameters

projectSlugstring required

Project slug (human-readable identifier)

Project slug (human-readable identifier)

sessionIdstring required

Session identifier lifted from instrumentation. Up to 128 characters.

Session identifier lifted from instrumentation. Up to 128 characters.

Response

Session detail

organizationIdstring required

Organization that owns this session.

projectIdstring required

Project this session belongs to.

sessionIdstring required

Session identifier set by the SDK. Groups the traces of one conversation.

traceCountinteger required

Number of traces in the session.

traceIdsstring[] required

Identifiers of the traces that make up the session.

spanCountinteger required

Total number of spans across the session's traces.

errorCountinteger required

Number of spans flagged with an error status.

startTimestring required

ISO-8601 timestamp of the session's earliest span.

endTimestring required

ISO-8601 timestamp of the session's latest span.

lastActivityTimestring required

ISO-8601 timestamp of the session's most recent span start.

durationNsnumber required

Active execution time of the session in nanoseconds, not wall-clock.

timeToFirstTokenNsnumber required

Nanoseconds from the start of the first LLM span to its first emitted token. 0 if not measured.

tokensInputnumber required

Total input tokens across the session's LLM spans.

tokensOutputnumber required

Total output tokens across the session's LLM spans.

tokensCacheReadnumber required

Total tokens served from the provider's prompt cache.

tokensCacheCreatenumber required

Total tokens written to the provider's prompt cache.

tokensReasoningnumber required

Total reasoning tokens reported by the model.

tokensTotalnumber required

Sum of all token counters.

costInputMicrocentsnumber required

Cost of input tokens in microcents (100,000,000 per USD).

costOutputMicrocentsnumber required

Cost of output tokens in microcents (100,000,000 per USD).

costTotalMicrocentsnumber required

Total cost in microcents (100,000,000 per USD).

userIdstring nullable required

End-user identifier set by the SDK. null when absent.

userEmailstring nullable required

End-user email set by the SDK. null when absent.

simulationIdstring nullable required

CUID of the simulation that produced this session. null when not a simulation.

tagsstring[] required

Free-form tags attached at ingest time.

metadataobject required

Free-form metadata attached at ingest time.

modelsstring[] required

Model identifiers seen across the session's LLM spans.

providersstring[] required

LLM-provider identifiers seen across the session's spans.

serviceNamesstring[] required

OpenTelemetry service.name values seen in the session.

agentNamesstring[] required

Agent names seen across the session's spans.

definedToolsstring[] required

Tool names declared available across the session's spans.

rootSpanIdstring nullable required

Identifier of the session's root span. null when no root span has been ingested.

rootSpanNamestring nullable required

name attribute of the root span. null when no root span has been ingested.

latestTraceIdstring nullable required

Identifier of the trace that produced the session's latest output. null when no trace produced output.

conversationGenAIMessage[] required

Conversation of the session, in OpenTelemetry GenAI format: the system instructions, then the messages of the session's latest LLM completion, followed by its generated output.

Changes

Changed in 1 of the 67 revisions of this API.1