System prompt not part of model spans

[robin-fiddler]

According to the gen_ai OpenTelemetry convention, system prompts/instructions should be represented as events. Also, the attribute key used is "system_prompt" whereas sem conv states it as "gen_ai.system.message".

In Strands, I can currently see the System Prompt only at the Agent span level. It is not being passed into the Model (chat) span.

For comparison, in other frameworks such as LangSmith, the system prompt appears in the model span as system messages. Since system prompts are eventually passed down to the LLM, they should ideally also be included in the Model span to maintain consistency and observability.

Expected Behavior
• The system prompt should be available in the Model (chat) span (in addition to being visible in the Agent span).
• This ensures parity with other frameworks and makes the tracing more consistent with the gen_ai convention.

Suggested Action
• Update the instrumentation so that system prompts are propagated to the Model span.
• Confirm alignment with the gen_ai semantic convention for proper OTEL trace representation.

Agent Span

{
    "name": "invoke_agent Strands Agents",
    "context": {
        "trace_id": "0xf820e5458e52a45d5f3946cf10b491bb",
        "span_id": "0xf817db76bcd18558",
        "trace_state": "[]"
    },
    "kind": "SpanKind.CLIENT",
    "parent_id": null,
    "start_time": "2025-07-30T10:33:36.407693Z",
    "end_time": "2025-07-30T10:33:42.824321Z",
    "status": {
        "status_code": "OK"
    },
    "attributes": {
        "gen_ai.event.start_time": "2025-07-30T10:33:36.407708+00:00",
        "gen_ai.system": "strands-agents",
        "gen_ai.agent.name": "Strands Agents",
        "gen_ai.operation.name": "invoke_agent",
        "gen_ai.request.model": "gpt-4o-mini",
        "gen_ai.agent.tools": "[\"book_hotel\", \"search_hotel\", \"book_flight\"]",
        "system_prompt": "\nYou are a travel agent capable of booking a hotel and a flight.\nYou have access to the following tools: book_hotel, search_hotel, book_flight.\nYou can use the tools to book a hotel and a flight for a given date.\nYou can also use the tools to search for a hotel and a flight for a given date.\nYou can also use the tools to book a hotel and a flight for a given date.\nYou can also use the tools to search for a hotel and a flight for a given date.\n",
        "gen_ai.event.end_time": "2025-07-30T10:33:42.824290+00:00",
        "gen_ai.usage.prompt_tokens": 1170,
        "gen_ai.usage.completion_tokens": 181,
        "gen_ai.usage.input_tokens": 1170,
        "gen_ai.usage.output_tokens": 181,
        "gen_ai.usage.total_tokens": 1351
    },
    "events": [
        {
            "name": "gen_ai.user.message",
            "timestamp": "2025-07-30T10:33:36.408888Z",
            "attributes": {
                "content": "[{\"text\": \"book a flight from tokyo to new york. book a stay in any hotel in new york. I am traveling on 1st aug 2025.\"}]"
            }
        },
        {
            "name": "gen_ai.choice",
            "timestamp": "2025-07-30T10:33:42.824279Z",
            "attributes": {
                "message": "Your travel arrangements have been successfully made:\n\n- **Flight**: Booked from **Tokyo** to **New York** for **August 1, 2025**.\n- **Hotel**: Stayed booked at **The Grand Hotel, New York** for the same date (August 1, 2025).\n\nIf you need any further assistance or additional bookings, feel free to ask!\n",
                "finish_reason": "end_turn"
            }
        }
    ],
    "links": [],
    "resource": {
        "attributes": {
            "telemetry.sdk.language": "python",
            "telemetry.sdk.name": "opentelemetry",
            "telemetry.sdk.version": "1.35.0",
            "service.name": "strands-agents",
            "service.version": "1.1.0"
        },
        "schema_url": ""
    }
}

Model (or chat) Span

{
    "name": "chat",
    "context": {
        "trace_id": "0xf820e5458e52a45d5f3946cf10b491bb",
        "span_id": "0x536e8c619dd04fc8",
        "trace_state": "[]"
    },
    "kind": "SpanKind.CLIENT",
    "parent_id": "0xc4e37fe6ab516e7e",
    "start_time": "2025-07-30T10:33:40.861714Z",
    "end_time": "2025-07-30T10:33:42.822629Z",
    "status": {
        "status_code": "OK"
    },
    "attributes": {
        "gen_ai.event.start_time": "2025-07-30T10:33:40.861716+00:00",
        "gen_ai.system": "strands-agents",
        "gen_ai.operation.name": "chat",
        "gen_ai.request.model": "gpt-4o-mini",
        "gen_ai.event.end_time": "2025-07-30T10:33:42.822578+00:00",
        "gen_ai.usage.prompt_tokens": 465,
        "gen_ai.usage.input_tokens": 465,
        "gen_ai.usage.completion_tokens": 80,
        "gen_ai.usage.output_tokens": 80,
        "gen_ai.usage.total_tokens": 545
    },
    "events": [
        {
            "name": "gen_ai.user.message",
            "timestamp": "2025-07-30T10:33:40.861740Z",
            "attributes": {
                "content": "[{\"text\": \"book a flight from tokyo to new york. book a stay in any hotel in new york. I am traveling on 1st aug 2025.\"}]"
            }
        },
        {
            "name": "gen_ai.assistant.message",
            "timestamp": "2025-07-30T10:33:40.861765Z",
            "attributes": {
                "content": "[{\"toolUse\": {\"toolUseId\": \"call_OpXsCHBLpJqVAvPATihbzcY0\", \"name\": \"book_flight\", \"input\": {\"from_airport\": \"Tokyo\", \"to_airport\": \"New York\", \"date\": \"2025-08-01\"}}}, {\"toolUse\": {\"toolUseId\": \"call_hV4ngBZaYTnZBAtqRNG4EtJH\", \"name\": \"search_hotel\", \"input\": {\"city\": \"New York\", \"date\": \"2025-08-01\"}}}]"
            }
        },
        {
            "name": "gen_ai.user.message",
            "timestamp": "2025-07-30T10:33:40.861785Z",
            "attributes": {
                "content": "[{\"toolResult\": {\"toolUseId\": \"call_OpXsCHBLpJqVAvPATihbzcY0\", \"status\": \"success\", \"content\": [{\"text\": \"Successfully booked a flight from Tokyo to New York for 2025-08-01.\"}]}}, {\"toolResult\": {\"toolUseId\": \"call_hV4ngBZaYTnZBAtqRNG4EtJH\", \"status\": \"success\", \"content\": [{\"text\": \"The Grand Hotel, New York, 2025-08-01\"}]}}]"
            }
        },
        {
            "name": "gen_ai.assistant.message",
            "timestamp": "2025-07-30T10:33:40.861799Z",
            "attributes": {
                "content": "[{\"toolUse\": {\"toolUseId\": \"call_QeEDMerAzOQKzCrK2ir3Tco0\", \"name\": \"book_hotel\", \"input\": {\"hotel_name\": \"The Grand Hotel\", \"date\": \"2025-08-01\"}}}]"
            }
        },
        {
            "name": "gen_ai.user.message",
            "timestamp": "2025-07-30T10:33:40.861813Z",
            "attributes": {
                "content": "[{\"toolResult\": {\"toolUseId\": \"call_QeEDMerAzOQKzCrK2ir3Tco0\", \"status\": \"success\", \"content\": [{\"text\": \"Successfully booked a stay at The Grand Hotel for 2025-08-01.\"}]}}]"
            }
        },
        {
            "name": "gen_ai.choice",
            "timestamp": "2025-07-30T10:33:42.822564Z",
            "attributes": {
                "finish_reason": "end_turn",
                "message": "[{\"text\": \"Your travel arrangements have been successfully made:\\n\\n- **Flight**: Booked from **Tokyo** to **New York** for **August 1, 2025**.\\n- **Hotel**: Stayed booked at **The Grand Hotel, New York** for the same date (August 1, 2025).\\n\\nIf you need any further assistance or additional bookings, feel free to ask!\"}]"
            }
        }
    ],
    "links": [],
    "resource": {
        "attributes": {
            "telemetry.sdk.language": "python",
            "telemetry.sdk.name": "opentelemetry",
            "telemetry.sdk.version": "1.35.0",
            "service.name": "strands-agents",
            "service.version": "1.1.0"
        },
        "schema_url": ""
    }
}