> ## 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.

# Agent eventlog readback

## Overview

This example enables `EventLog` file logging for the default agent runtime,
executes one simple agent run, then reads the generated JSONL file and prints
the captured agent lifecycle entries on screen.

Key concepts:

* `EventLog::enable()`: activates the default JSONL sink
* `AgentLoop::default()`: uses the default agent runtime event bus
* JSONL readback: inspect execution lifecycle after the run completes

## Example

```php theme={null}
<?php
require 'examples/boot.php';
require_once 'examples/_support/eventlog_readback.php';

use Cognesy\Agents\AgentLoop;
use Cognesy\Agents\Data\AgentState;
use Cognesy\Agents\Enums\ExecutionStatus;
use Cognesy\Logging\EventLog;
use Cognesy\Messages\Messages;

$logPath = ExampleEventLog::path('examples-d05-agent-eventlog');

EventLog::enable($logPath);

try {
    $loop = AgentLoop::default();
    $state = AgentState::empty()->withMessages(
        Messages::fromString('What are the three primary colors? Answer in one sentence.')
    );

    $finalState = $loop->execute($state);
    $entries = ExampleEventLog::read($logPath);
} finally {
    EventLog::disable();
}

$response = $finalState->finalResponse()->toString() ?: 'No response';

echo "=== Agent Result ===\n";
echo "Answer: {$response}\n";
echo "Steps: {$finalState->stepCount()}\n";
echo "Status: {$finalState->status()->value}\n";

echo "\n=== EventLog Entries ===\n";
echo "Log file: {$logPath}\n";
echo 'Entries captured: ' . count($entries) . "\n\n";

ExampleEventLog::print($entries, 8);

assert($finalState->status() === ExecutionStatus::Completed);
assert($response !== '');
assert($entries !== []);
?>
```