Add AI agent detection to auto-switch to raw output

Switch from JSON to raw error format for AI agents. The raw format
outputs one error per line as file:line:message, which saves ~49%
tokens compared to JSON for typical error output (and 100% for
zero-error runs.

When an agent is detected, progress bar output is fully suppressed
(equivalent to --no-progress), eliminating redraw noise that wastes
tokens in agent context windows.

Token comparison (3 errors across 2 files):
- JSON: ~185 tokens (678 chars) with structural overhead per error
- Raw:   ~95 tokens (295 chars) with just file:line:message per line

Zero errors:
- JSON: ~18 tokens for empty structure
- Raw:    0 tokens (no output)

Explicit --error-format=table or config errorFormat: table always
takes priority over agent detection.

Author: pushpak1300

src/Command/AnalyseCommand.php

@@ -5,6 +5,7 @@
 use OndraM\CiDetector\CiDetector;
 use Override;
 use PHPStan\Analyser\InternalError;
+use PHPStan\Command\ErrorFormatter\AgentDetectedErrorFormatter;
 use PHPStan\Command\ErrorFormatter\BaselineNeonErrorFormatter;
 use PHPStan\Command\ErrorFormatter\BaselinePhpErrorFormatter;
 use PHPStan\Command\ErrorFormatter\ErrorFormatter;
@@ -235,11 +236,20 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			$errorFormat = $inceptionResult->getContainer()->getParameter('errorFormat');
 		}
 
+		$container = $inceptionResult->getContainer();
+
+		if ($errorFormat === null) {
+			/** @var AgentDetectedErrorFormatter $agentFormatter */
+			$agentFormatter = $container->getByType(AgentDetectedErrorFormatter::class);
+			if ($agentFormatter->isAgentDetected()) {
+				$errorFormat = 'raw';
+			}
+		}
+
 		if ($errorFormat === null) {
 			$errorFormat = 'table';
 		}
 
-		$container = $inceptionResult->getContainer();
 		$errorFormatterServiceName = sprintf('errorFormatter.%s', $errorFormat);
 		if (!$container->hasService($errorFormatterServiceName)) {
 			$errorOutput->writeLineFormatted(sprintf(

src/Command/ErrorFormatter/AgentDetectedErrorFormatter.php

@@ -0,0 +1,53 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Command\ErrorFormatter;
+
+use PHPStan\Command\AnalysisResult;
+use PHPStan\Command\Output;
+use PHPStan\DependencyInjection\AutowiredParameter;
+use PHPStan\DependencyInjection\AutowiredService;
+use function file_exists;
+use function getenv;
+use function is_string;
+use function trim;
+
+/**
+ * @api
+ */
+#[AutowiredService(as: AgentDetectedErrorFormatter::class)]
+final class AgentDetectedErrorFormatter implements ErrorFormatter
+{
+
+	public function __construct(
+		#[AutowiredParameter(ref: '@errorFormatter.raw')]
+		private RawErrorFormatter $rawErrorFormatter,
+	)
+	{
+	}
+
+	public function isAgentDetected(): bool
+	{
+		$aiAgent = getenv('AI_AGENT');
+		if (is_string($aiAgent) && trim($aiAgent) !== '') {
+			return true;
+		}
+
+		return getenv('CURSOR_TRACE_ID') !== false
+			|| getenv('CURSOR_AGENT') !== false
+			|| getenv('GEMINI_CLI') !== false
+			|| getenv('CODEX_SANDBOX') !== false
+			|| getenv('AUGMENT_AGENT') !== false
+			|| getenv('OPENCODE_CLIENT') !== false
+			|| getenv('OPENCODE') !== false
+			|| getenv('CLAUDECODE') !== false
+			|| getenv('CLAUDE_CODE') !== false
+			|| getenv('REPL_ID') !== false
+			|| file_exists('/opt/.devin');
+	}
+
+	public function formatErrors(AnalysisResult $analysisResult, Output $output): int
+	{
+		return $this->rawErrorFormatter->formatErrors($analysisResult, $output);
+	}
+
+}

src/Command/ErrorsConsoleStyle.php

@@ -15,7 +15,11 @@
 use function explode;
 use function implode;
 use function sprintf;
+use function file_exists;
+use function getenv;
+use function is_string;
 use function strlen;
+use function trim;
 use const DIRECTORY_SEPARATOR;
 
 final class ErrorsConsoleStyle extends SymfonyStyle
@@ -29,10 +33,13 @@ final class ErrorsConsoleStyle extends SymfonyStyle
 
 	private ?bool $isCiDetected = null;
 
+	private ?bool $isAgentDetected = null;
+
 	public function __construct(InputInterface $input, OutputInterface $output)
 	{
 		parent::__construct($input, $output);
-		$this->showProgress = $input->hasOption(self::OPTION_NO_PROGRESS) && !(bool) $input->getOption(self::OPTION_NO_PROGRESS);
+		$showProgress = $input->hasOption(self::OPTION_NO_PROGRESS) && !(bool) $input->getOption(self::OPTION_NO_PROGRESS);
+		$this->showProgress = $showProgress && !$this->isAgentDetected();
 	}
 
 	private function isCiDetected(): bool
@@ -45,6 +52,27 @@ private function isCiDetected(): bool
 		return $this->isCiDetected;
 	}
 
+	private function isAgentDetected(): bool
+	{
+		if ($this->isAgentDetected === null) {
+			$aiAgent = getenv('AI_AGENT');
+			$this->isAgentDetected = (is_string($aiAgent) && trim($aiAgent) !== '')
+				|| getenv('CURSOR_TRACE_ID') !== false
+				|| getenv('CURSOR_AGENT') !== false
+				|| getenv('GEMINI_CLI') !== false
+				|| getenv('CODEX_SANDBOX') !== false
+				|| getenv('AUGMENT_AGENT') !== false
+				|| getenv('OPENCODE_CLIENT') !== false
+				|| getenv('OPENCODE') !== false
+				|| getenv('CLAUDECODE') !== false
+				|| getenv('CLAUDE_CODE') !== false
+				|| getenv('REPL_ID') !== false
+				|| file_exists('/opt/.devin');
+		}
+
+		return $this->isAgentDetected;
+	}
+
 	/**
 	 * @param string[] $headers
 	 * @param string[][] $rows
@@ -95,9 +123,10 @@ public function createProgressBar(int $max = 0): ProgressBar
 		}
 
 		$ci = $this->isCiDetected();
-		$this->progressBar->setOverwrite(!$ci);
+		$agent = $this->isAgentDetected();
+		$this->progressBar->setOverwrite(!$ci && !$agent);
 
-		if ($ci) {
+		if ($ci || $agent) {
 			$this->progressBar->minSecondsBetweenRedraws(15);
 			$this->progressBar->maxSecondsBetweenRedraws(30);
 		} elseif (DIRECTORY_SEPARATOR === '\\') {

tests/PHPStan/Command/ErrorFormatter/AgentDetectedErrorFormatterTest.php

@@ -0,0 +1,84 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Command\ErrorFormatter;
+
+use Override;
+use PHPStan\Testing\ErrorFormatterTestCase;
+use function putenv;
+
+class AgentDetectedErrorFormatterTest extends ErrorFormatterTestCase
+{
+
+	#[Override]
+	protected function setUp(): void
+	{
+		putenv('AI_AGENT');
+		putenv('CURSOR_TRACE_ID');
+		putenv('CURSOR_AGENT');
+		putenv('GEMINI_CLI');
+		putenv('CODEX_SANDBOX');
+		putenv('AUGMENT_AGENT');
+		putenv('OPENCODE_CLIENT');
+		putenv('OPENCODE');
+		putenv('CLAUDECODE');
+		putenv('CLAUDE_CODE');
+		putenv('REPL_ID');
+	}
+
+	#[Override]
+	protected function tearDown(): void
+	{
+		putenv('AI_AGENT');
+		putenv('CLAUDE_CODE');
+	}
+
+	public function testIsAgentDetectedReturnsFalse(): void
+	{
+		$formatter = new AgentDetectedErrorFormatter(new RawErrorFormatter());
+		$this->assertFalse($formatter->isAgentDetected());
+	}
+
+	public function testIsAgentDetectedReturnsTrueWithAiAgent(): void
+	{
+		putenv('AI_AGENT=test');
+		$formatter = new AgentDetectedErrorFormatter(new RawErrorFormatter());
+		$this->assertTrue($formatter->isAgentDetected());
+	}
+
+	public function testIsAgentDetectedReturnsTrueWithClaudeCode(): void
+	{
+		putenv('CLAUDE_CODE=1');
+		$formatter = new AgentDetectedErrorFormatter(new RawErrorFormatter());
+		$this->assertTrue($formatter->isAgentDetected());
+	}
+
+	public function testFormatErrorsProducesRawOutput(): void
+	{
+		$formatter = new AgentDetectedErrorFormatter(new RawErrorFormatter());
+
+		$exitCode = $formatter->formatErrors(
+			$this->getAnalysisResult(1, 0),
+			$this->getOutput(),
+		);
+
+		$this->assertSame(1, $exitCode);
+		$this->assertSame(
+			'/data/folder/with space/and unicode 😃/project/folder with unicode 😃/file name with "spaces" and unicode 😃.php:4:Foo' . "\n",
+			$this->getOutputContent(),
+		);
+	}
+
+	public function testFormatErrorsNoErrors(): void
+	{
+		$formatter = new AgentDetectedErrorFormatter(new RawErrorFormatter());
+
+		$exitCode = $formatter->formatErrors(
+			$this->getAnalysisResult(0, 0),
+			$this->getOutput(),
+		);
+
+		$this->assertSame(0, $exitCode);
+		$this->assertSame('', $this->getOutputContent());
+	}
+
+}