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

# 06 logfire

# Logfire Setup

The simplest Logfire setup uses:

* `LogfireConfig`
* `LogfireExporter`
* `Telemetry`

## Minimal Example

```php theme={null}
use Cognesy\Telemetry\Adapters\Logfire\LogfireConfig;
use Cognesy\Telemetry\Adapters\Logfire\LogfireExporter;
use Cognesy\Telemetry\Application\Registry\TraceRegistry;
use Cognesy\Telemetry\Application\Telemetry;

$telemetry = new Telemetry(
    registry: new TraceRegistry(),
    exporter: new LogfireExporter(new LogfireConfig(
        endpoint: 'https://logfire-eu.pydantic.dev',
        serviceName: 'my-service',
        headers: ['Authorization' => $_ENV['LOGFIRE_TOKEN']],
    )),
);
// @doctest id="9861"
```

## Environment Variables

The telemetry examples use:

* `LOGFIRE_TOKEN`
* `LOGFIRE_OTLP_ENDPOINT`

Use `LOGFIRE_TOKEN` as the Logfire write token for OTLP telemetry export.

## Endpoint Rule

`LogfireConfig` expects the OTLP base endpoint. Do not pass a full `/v1/traces`
or `/v1/metrics` path.

## Reference Example

The inline reference example is:

* `examples/A03_Troubleshooting/TelemetryLogfire/run.php`

## Agent Runtime Example

The working agent example is:

* `examples/D05_AgentTroubleshooting/TelemetryLogfire/run.php`

## Subagent Example

For nested parent and child traces, see:

* `examples/D05_AgentTroubleshooting/SubagentTelemetryLogfire/run.php`

## Notes

* `LogfireExporter` requires either `LogfireConfig` or a custom transport
* service name comes from `LogfireConfig::serviceName()`
* if export fails with a 4xx response, check the token and endpoint first