OpenTelemetry tracing does not set the span kind

[ssowerby]

When attempting to use OpenTelemetryTracingBackend in the opentelemetry-backend module with sttp 4.0.13 it seems the spans emitted do not have the span kind set to CLIENT as expected. So right now they appear as the default kind INTERNAL.

From a quick search of all the sttp code it seems both the otel4s-tracing-backend and opentelemetry-tracing-zio-backend do set the kind as expected.

It seems simply adding .setSpanKind(SpanKind.CLIENT) when using the SpanBuilder at observability/opentelemetry-backend/src/main/scala/sttp/client4/opentelemetry/OpenTelemetryTracingBackend.scala:55 would be sufficient.

[adamw]

@claude can you try creating a PR for this issue?

[claude]

Claude finished @adamw's task in 1m 39s —— View job • claude/issue-2762-20260116-1015 • Create PR ➔

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Tasks

• Read repository setup instructions (CLAUDE.md)
• Examine the OpenTelemetryTracingBackend file
• Check how other backends implement span kind
• Add .setSpanKind(SpanKind.CLIENT) to the SpanBuilder
• Commit and push changes
• Provide PR creation link

Summary

I've successfully fixed the issue by adding .setSpanKind(SpanKind.CLIENT) to the OpenTelemetryTracingBackend span builder. This ensures that spans are correctly marked as CLIENT kind instead of the default INTERNAL kind, matching the behavior of the other tracing backends in the codebase.

Changes Made

• Added import for io.opentelemetry.api.trace.SpanKind at observability/opentelemetry-backend/src/main/scala/sttp/client4/opentelemetry/OpenTelemetryTracingBackend.scala:4
• Added .setSpanKind(SpanKind.CLIENT) to the span builder chain at observability/opentelemetry-backend/src/main/scala/sttp/client4/opentelemetry/OpenTelemetryTracingBackend.scala:56

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