Function startLLMRequestSpan

src/utils/telemetry/sessionTracing.ts:274–340

(
  model: string,
  newContext?: LLMRequestNewContext,
  messagesForAPI?: APIMessage[],
  fastMode?: boolean,
)

}

export function startLLMRequestSpan(
  model: string,
  newContext?: LLMRequestNewContext,
  messagesForAPI?: APIMessage[],
  fastMode?: boolean,
): Span {
  // Start Perfetto span regardless of OTel tracing state
  const perfettoSpanId = isPerfettoTracingEnabled()
    ? startLLMRequestPerfettoSpan({
        model,
        querySource: newContext?.querySource,
        messageId: undefined, // Will be set in endLLMRequestSpan
      })
    : undefined

  if (!isAnyTracingEnabled()) {
    // Still track Perfetto span even if OTel is disabled
    if (perfettoSpanId) {
      const dummySpan = trace.getActiveSpan() || getTracer().startSpan('dummy')
      const spanId = getSpanId(dummySpan)
      const spanContextObj: SpanContext = {
        span: dummySpan,
        startTime: Date.now(),
        attributes: { model },
        perfettoSpanId,
      }
      activeSpans.set(spanId, new WeakRef(spanContextObj))
      strongSpans.set(spanId, spanContextObj)
      return dummySpan
    }
    return trace.getActiveSpan() || getTracer().startSpan('dummy')
  }

  const tracer = getTracer()
  const parentSpanCtx = interactionContext.getStore()

  const attributes = createSpanAttributes('llm_request', {
    model: model,
    'llm_request.context': parentSpanCtx ? 'interaction' : 'standalone',
    speed: fastMode ? 'fast' : 'normal',
  })

  const ctx = parentSpanCtx
    ? trace.setSpan(otelContext.active(), parentSpanCtx.span)
    : otelContext.active()
  const span = tracer.startSpan('claude_code.llm_request', { attributes }, ctx)

  // Add query_source (agent name) if provided
  if (newContext?.querySource) {
    span.setAttribute('query_source', newContext.querySource)
  }

  // Add experimental attributes (system prompt, new_context)
  addBetaLLMRequestAttributes(span, newContext, messagesForAPI)

  const spanId = getSpanId(span)
  const spanContextObj: SpanContext = {
    span,