Python: System instructions duplicated in telemetry: appears in both gen_ai.system_instructions and gen_ai.input_messages

[singankit]

Bug Description

When running the basic responses sample from foundry-samples, the generated traces contain the system instructions duplicated in two span attributes:

• gen_ai.system_instructions (correct)
• gen_ai.input_messages (unexpected — system instructions should not appear here alongside user messages)

Steps to Reproduce

1. Run the basic hosted-agent sample: https://github.com/microsoft-foundry/foundry-samples/blob/main/samples/python/hosted-agents/agent-framework/responses/01-basic/
2. Observe the generated OTel traces (e.g. in Application Insights or a local exporter)
3. Notice that the system instructions text appears in both gen_ai.system_instructions and gen_ai.input_messages attributes on the same span

Expected Behavior

System instructions should only appear in gen_ai.system_instructions. The gen_ai.input_messages attribute should only contain user/assistant messages (the conversation history), not the system prompt.

Actual Behavior

System instructions are duplicated — present in both gen_ai.system_instructions and gen_ai.input_messages.

Environment

• Python agent-framework (latest)
• OpenTelemetry tracing enabled
• Observed via Application Insights