# Send traces from Python

> Send traces of OpenAI calls from Python with the OpenTelemetry GenAI instrumentation.

This guide sends traces from a Python application that uses the `openai` package, with OpenTelemetry's own instrumentation. Tracing reads the model, tokens, prompt and completion of each call.

## Before you start

You need an API key with the `traces:write` scope. Create one under **Settings** in the dashboard, or run `div login`.

## Send traces

1. Install the packages.

   ```bash
   pip install opentelemetry-sdk opentelemetry-exporter-otlp-proto-http opentelemetry-instrumentation-openai-v2
   ```

2. Set the exporter's endpoint and key, and name your service.

   ```bash
   export OTEL_EXPORTER_OTLP_ENDPOINT=https://api.divergentlabs.xyz/api/otlp
   export OTEL_EXPORTER_OTLP_HEADERS="Authorization=Bearer%20$DIVERGENT_API_KEY"
   export OTEL_EXPORTER_OTLP_COMPRESSION=gzip
   export OTEL_SERVICE_NAME=my-app
   ```

3. Record prompts and completions on the spans. Without these two variables, the spans carry the model and tokens and no content.

   ```bash
   export OTEL_SEMCONV_STABILITY_OPT_IN=gen_ai_latest_experimental
   export OTEL_INSTRUMENTATION_GENAI_CAPTURE_MESSAGE_CONTENT=SPAN_ONLY
   ```

4. Set up the tracer provider before your application creates its OpenAI client, and shut it down before the process exits, so the last spans are sent.

   ```python
   from opentelemetry import trace
   from opentelemetry.sdk.trace import TracerProvider
   from opentelemetry.sdk.trace.export import BatchSpanProcessor
   from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
   from opentelemetry.instrumentation.openai_v2 import OpenAIInstrumentor

   provider = TracerProvider()
   provider.add_span_processor(BatchSpanProcessor(OTLPSpanExporter()))
   trace.set_tracer_provider(provider)
   OpenAIInstrumentor().instrument()
   ```

5. Run your application, then list the traces.

   ```bash
   div traces --since 10m
   ```

## Group calls into one trace

Each call is its own trace unless it runs inside a span of yours. Wrap a request or a task in a span, and set `session.id` and `user.id` on it to filter traces by them later:

```python
tracer = trace.get_tracer("my-app")

with tracer.start_as_current_span("answer question") as span:
    span.set_attribute("session.id", session_id)
    span.set_attribute("user.id", user_id)
    client.chat.completions.create(model="gpt-4o-mini", messages=messages)
```

```bash
div traces --session "$SESSION_ID"
```

## Keep content out of traces

Set `OTEL_INSTRUMENTATION_GENAI_CAPTURE_MESSAGE_CONTENT=NO_CONTENT`, or leave it unset. Spans then carry the model, tokens and timings, and no prompts or completions.

## Large prompts

An export over 4 MiB is refused with `payload_too_large`, and the exporter drops that batch. If your prompts are long, send smaller batches:

```bash
export OTEL_BSP_MAX_EXPORT_BATCH_SIZE=128
```