Add pi detection (#7)

Author: ssnepenthe

README.md

@@ -61,6 +61,7 @@ $result = detectAgent();
 | Replit | `REPL_ID` env var |
 | Devin | `/opt/.devin` file exists |
 | Antigravity | `ANTIGRAVITY_AGENT` env var |
+| Pi | `PI_CODING_AGENT` env var |
 
 ### Custom Agent
 

src/AgentDetector.php

@@ -25,6 +25,7 @@ public static function detect(): AgentResult
             'replit' => ['REPL_ID'],
             'copilot' => ['COPILOT_CLI'],
             'antigravity' => ['ANTIGRAVITY_AGENT'],
+            'pi' => ['PI_CODING_AGENT'],
         ];
 
         foreach ($agentsWithEnvVars as $agent => $envVars) {

src/KnownAgent.php

@@ -17,4 +17,5 @@ enum KnownAgent: string
     case Amp = 'amp';
     case Copilot = 'copilot';
     case Antigravity = 'antigravity';
+    case Pi = 'pi';
 }

tests/AgentDetectorTest.php

@@ -23,6 +23,7 @@
         'COPILOT_CLI',
         'REPL_ID',
         'ANTIGRAVITY_AGENT',
+        'PI_CODING_AGENT',
     ] as $var) {
         putenv($var);
     }
@@ -46,6 +47,7 @@
         'COPILOT_CLI',
         'REPL_ID',
         'ANTIGRAVITY_AGENT',
+        'PI_CODING_AGENT',
     ] as $var) {
         putenv($var);
     }
@@ -202,6 +204,16 @@
         ->and($result->knownAgent())->toBe(KnownAgent::Antigravity);
 });
 
+it('detects pi via PI_CODING_AGENT', function (): void {
+    putenv('PI_CODING_AGENT=true');
+
+    $result = AgentDetector::detect();
+
+    expect($result->isAgent)->toBeTrue()
+        ->and($result->name)->toBe('pi')
+        ->and($result->knownAgent())->toBe(KnownAgent::Pi);
+});
+
 // Devin detection via file_exists mock
 it('detects devin via /opt/.devin file', function (): void {
     $GLOBALS['__mock_file_exists'] = fn (string $path): bool => $path === '/opt/.devin';
@@ -317,6 +329,7 @@
     'claude' => ['CLAUDECODE', '1', KnownAgent::Claude],
     'replit' => ['REPL_ID', 'id', KnownAgent::Replit],
     'antigravity' => ['ANTIGRAVITY_AGENT', '1', KnownAgent::Antigravity],
+    'pi' => ['PI_CODING_AGENT', 'true', KnownAgent::Pi],
 ]);
 
 it('returns null knownAgent for custom agent', function (): void {