[BUG] Claude harness: Claude Code exports no spans against the real Anthropic API #2922

Disclosure: this issue was drafted by an AI agent (Claude) while testing kagent 1.x on Agent
Substrate, and reviewed by a human before filing.

Severity: Medium · tracing enabled, Claude harness with the real Anthropic API · no workaround found

What happens

As a user I turn on tracing and send a turn to an agent on the claude Harness. The trace holds only
the harness runtime's spans (invoke_agent and the A2A and gRPC spans around it). There is no
claude_code.* span, so the model calls and tool calls inside Claude Code are not traced (2 of 2
runs). The same setup on the kagent runtime has generate_content spans, and on the Codex harness
run_sampling_request spans.

The egress gateway log for the Claude actor during the turn shows that Claude Code never calls the
OTLP endpoint. Both Export calls come from the harness runtime's Go exporter:

2  api.anthropic.com                  /v1/messages?beta=true                                        200
2  api.anthropic.com                  /api/event_logging/v2/batch                                   200
1  api.anthropic.com                  /api/eval/sdk-…                                               200
1  api.anthropic.com                  /api/claude_code/metrics                                      200
2  jaeger.jaeger.svc.cluster.local    /opentelemetry.proto.collector.trace.v1.TraceService/Export   200
   user-agent of both Export calls: "OTel OTLP Exporter Go/1.45.0 grpc-go/1.83.2"

The collector is reachable from the actor, and Claude Code does send its own telemetry to
api.anthropic.com, but it sends no span to the configured collector.

Reproduce

kagent v1.0.0-alpha2 on Agent Substrate, the chart's otel.tracing pointed at an OTLP gRPC
collector (Jaeger http://jaeger.jaeger.svc.cluster.local:4317), a claude Harness, and an
AgentTemplate with an Anthropic ModelConfig (real API key). Send one turn, then list the span names
of its trace, and read
kubectl -n ate-system logs deploy/atenet-egress -c agentgateway | grep ai-<instance id>.

Expected vs actual

• Expected: the trace holds claude_code.* spans for the model and tool calls, as the e2e test
  requires.
• Actual: only the harness runtime's spans; Claude Code makes no OTLP export.

Ask

Find why Claude Code does not export against the real API, and make the e2e test cover that path.

CLAUDE_CODE_ENABLE_TELEMETRY=1
CLAUDE_CODE_ENHANCED_TELEMETRY_BETA=1
OTEL_TRACES_EXPORTER=otlp
OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=http://jaeger.jaeger.svc.cluster.local:4317
OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=grpc
OTEL_METRICS_EXPORTER=none
OTEL_LOGS_EXPORTER=none
KAGENT_PRE_RESPONSE_TRACE_FLUSH=true