> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usefused.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configure one telemetry sink

> Send Harnest traces and logs to one OTLP collector.

Set one shared OTLP endpoint to export both traces and logs:

```bash theme={null}
export OTEL_SERVICE_NAME=support-agent
export OTEL_EXPORTER_OTLP_ENDPOINT=http://127.0.0.1:4318
export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
harnest serve support-agent
```

Setting an OTLP endpoint enables export automatically. Harnest includes the OTLP/HTTP exporter; no additional package is required. `OTEL_SERVICE_NAME` is optional and defaults to the compiled application name.

## Send only one signal

Use a signal-specific endpoint when the collector routes traces and logs separately, or when you want only one signal:

```bash Traces only theme={null}
export OTEL_EXPORTER_OTLP_TRACES_ENDPOINT=https://otel.example.com/v1/traces
export OTEL_EXPORTER_OTLP_TRACES_HEADERS="Authorization=Bearer%20${OTLP_TOKEN}"
export OTEL_EXPORTER_OTLP_TRACES_PROTOCOL=http/protobuf
```

```bash Logs only theme={null}
export OTEL_EXPORTER_OTLP_LOGS_ENDPOINT=https://otel.example.com/v1/logs
export OTEL_EXPORTER_OTLP_LOGS_HEADERS="Authorization=Bearer%20${OTLP_TOKEN}"
export OTEL_EXPORTER_OTLP_LOGS_PROTOCOL=http/protobuf
```

If only one signal-specific endpoint is set, Harnest disables export of the other signal.

## Runtime controls

| Variable                     | Effect                                         |
| ---------------------------- | ---------------------------------------------- |
| `OTEL_SERVICE_NAME`          | Sets the service identity                      |
| `HARNEST_LOG_LEVEL`          | Sets the minimum log level; defaults to `INFO` |
| `HARNEST_LOG_CONSOLE=false`  | Disables JSON logs on stderr                   |
| `HARNEST_OTEL_ENABLED=false` | Disables the environment-configured OTLP sink  |
| `OTEL_SDK_DISABLED=true`     | Disables the environment-configured OTLP sink  |

Standard OTLP headers, compression, timeout, resource, and sampling environment variables are passed to OpenTelemetry. Store tokens in deployment secrets.

<Card title="Need fan-out?" icon="arrows-split-up-and-left" href="/harnest/runtime/telemetry/multiple-sinks">
  Configure multiple in-process destinations.
</Card>