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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

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Example

<?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 !== []);
?>