diff --git a/system/Commands/Encryption/GenerateKey.php b/system/Commands/Encryption/GenerateKey.php
index ec5007560ed0..1e56365ec3aa 100644
--- a/system/Commands/Encryption/GenerateKey.php
+++ b/system/Commands/Encryption/GenerateKey.php
@@ -13,88 +13,108 @@
 
 namespace CodeIgniter\Commands\Encryption;
 
-use CodeIgniter\CLI\BaseCommand;
+use CodeIgniter\CLI\AbstractCommand;
+use CodeIgniter\CLI\Attributes\Command;
 use CodeIgniter\CLI\CLI;
+use CodeIgniter\CLI\Input\Option;
 use CodeIgniter\Config\DotEnv;
 use CodeIgniter\Encryption\Encryption;
 use Config\Paths;
 
 /**
- * Generates a new encryption key.
+ * Generates a new encryption key and writes it in an `.env` file.
  */
-class GenerateKey extends BaseCommand
+#[Command(name: 'key:generate', description: 'Generates a new encryption key and writes it in an `.env` file.', group: 'Encryption')]
+class GenerateKey extends AbstractCommand
 {
     /**
-     * The Command's group.
-     *
-     * @var string
+     * @var list<string>
      */
-    protected $group = 'Encryption';
+    private const VALID_PREFIXES = ['hex2bin', 'base64'];
 
-    /**
-     * The Command's name.
-     *
-     * @var string
-     */
-    protected $name = 'key:generate';
+    protected function configure(): void
+    {
+        $this
+            ->addOption(new Option(
+                name: 'force',
+                shortcut: 'f',
+                description: 'Force overwrite existing key in `.env` file.',
+            ))
+            ->addOption(new Option(
+                name: 'length',
+                description: 'The length of the random string that should be returned in bytes.',
+                requiresValue: true,
+                default: '32',
+            ))
+            ->addOption(new Option(
+                name: 'prefix',
+                description: 'Prefix to prepend to encoded key (either hex2bin or base64).',
+                requiresValue: true,
+                default: 'hex2bin',
+            ))
+            ->addOption(new Option(
+                name: 'show',
+                description: 'Shows the generated key in the terminal instead of storing in the `.env` file.',
+            ));
+    }
 
-    /**
-     * The Command's usage.
-     *
-     * @var string
-     */
-    protected $usage = 'key:generate [options]';
+    protected function interact(array &$arguments, array &$options): void
+    {
+        $prefix = $this->getUnboundOption('prefix', $options);
 
-    /**
-     * The Command's short description.
-     *
-     * @var string
-     */
-    protected $description = 'Generates a new encryption key and writes it in an `.env` file.';
+        if (is_string($prefix) && ! in_array($prefix, self::VALID_PREFIXES, true)) {
+            $options['prefix'] = CLI::prompt('Please provide a valid prefix to use.', self::VALID_PREFIXES, 'required');
+        }
 
-    /**
-     * The command's options
-     *
-     * @var array<string, string>
-     */
-    protected $options = [
-        '--force'  => 'Force overwrite existing key in `.env` file.',
-        '--length' => 'The length of the random string that should be returned in bytes. Defaults to 32.',
-        '--prefix' => 'Prefix to prepend to encoded key (either hex2bin or base64). Defaults to hex2bin.',
-        '--show'   => 'Shows the generated key in the terminal instead of storing in the `.env` file.',
-    ];
+        if ($this->hasUnboundOption('show', $options)) {
+            return;
+        }
 
-    /**
-     * Actually execute the command.
-     */
-    public function run(array $params)
-    {
-        $prefix = $params['prefix'] ?? CLI::getOption('prefix');
+        if ($this->hasUnboundOption('force', $options)) {
+            return;
+        }
 
-        if (in_array($prefix, [null, true], true)) {
-            $prefix = 'hex2bin';
-        } elseif (! in_array($prefix, ['hex2bin', 'base64'], true)) {
-            $prefix = CLI::prompt('Please provide a valid prefix to use.', ['hex2bin', 'base64'], 'required'); // @codeCoverageIgnore
+        if (env('encryption.key', '') === '') {
+            return;
         }
 
-        $length = $params['length'] ?? CLI::getOption('length');
+        if (CLI::prompt('Overwrite existing key?', ['n', 'y']) === 'y') {
+            $options['force'] = null; // simulate the presence of the --force option
+        }
+    }
+
+    protected function execute(array $arguments, array $options): int
+    {
+        $prefix = $options['prefix'];
 
-        if (in_array($length, [null, true], true)) {
-            $length = 32;
+        if (! in_array($prefix, self::VALID_PREFIXES, true)) {
+            CLI::error(sprintf('Invalid prefix "%s". Use either "hex2bin" or "base64".', $prefix));
+
+            return EXIT_ERROR;
         }
 
-        $encodedKey = $this->generateRandomKey($prefix, $length);
+        $encodedKey = $this->generateRandomKey($prefix, (int) $options['length']);
 
-        if (array_key_exists('show', $params) || (bool) CLI::getOption('show')) {
+        if ($options['show'] === true) {
             CLI::write($encodedKey, 'yellow');
-            CLI::newLine();
 
             return EXIT_SUCCESS;
         }
 
-        if (! $this->setNewEncryptionKey($encodedKey, $params)) {
-            CLI::write('Error in setting new encryption key to .env file.', 'light_gray', 'red');
-            CLI::newLine();
+        $currentKey = env('encryption.key', '');
+
+        if ($currentKey !== '' && $options['force'] === false) {
+            CLI::error('Setting new encryption key aborted.');
+
+            if (! $this->isInteractive()) {
+                CLI::error('If you want, use the "--force" option to force overwrite the existing key.');
+            }
+
+            return EXIT_ERROR;
+        }
+
+        if (! $this->writeNewEncryptionKeyToFile($currentKey, $encodedKey)) {
+            CLI::write('Error in setting new encryption key to .env file.');
 
             return EXIT_ERROR;
         }
@@ -114,7 +134,7 @@ public function run(array $params)
     /**
      * Generates a key and encodes it.
      */
-    protected function generateRandomKey(string $prefix, int $length): string
+    private function generateRandomKey(string $prefix, int $length): string
     {
         $key = Encryption::createKey($length);
 
@@ -125,37 +145,10 @@ protected function generateRandomKey(string $prefix, int $length): string
         return 'base64:' . base64_encode($key);
     }
 
-    /**
-     * Sets the new encryption key in your .env file.
-     *
-     * @param array<int|string, string|null> $params
-     */
-    protected function setNewEncryptionKey(string $key, array $params): bool
-    {
-        $currentKey = env('encryption.key', '');
-
-        if ($currentKey !== '' && ! $this->confirmOverwrite($params)) {
-            // Not yet testable since it requires keyboard input
-            return false; // @codeCoverageIgnore
-        }
-
-        return $this->writeNewEncryptionKeyToFile($currentKey, $key);
-    }
-
-    /**
-     * Checks whether to overwrite existing encryption key.
-     *
-     * @param array<int|string, string|null> $params
-     */
-    protected function confirmOverwrite(array $params): bool
-    {
-        return (array_key_exists('force', $params) || CLI::getOption('force')) || CLI::prompt('Overwrite existing key?', ['n', 'y']) === 'y';
-    }
-
     /**
      * Writes the new encryption key to .env file.
      */
-    protected function writeNewEncryptionKeyToFile(string $oldKey, string $newKey): bool
+    private function writeNewEncryptionKeyToFile(string $oldKey, string $newKey): bool
     {
         $baseEnv = ROOTPATH . 'env';
         $envFile = ((new Paths())->envDirectory ?? ROOTPATH) . '.env'; // @phpstan-ignore nullCoalesce.property
@@ -164,7 +157,6 @@ protected function writeNewEncryptionKeyToFile(string $oldKey, string $newKey):
             if (! is_file($baseEnv)) {
                 CLI::write('Both default shipped `env` file and custom `.env` are missing.', 'yellow');
                 CLI::write('Here\'s your new key instead: ' . CLI::color($newKey, 'yellow'));
-                CLI::newLine();
 
                 return false;
             }
@@ -195,7 +187,7 @@ protected function writeNewEncryptionKeyToFile(string $oldKey, string $newKey):
     /**
      * Get the regex of the current encryption key.
      */
-    protected function keyPattern(string $oldKey): string
+    private function keyPattern(string $oldKey): string
     {
         $escaped = preg_quote($oldKey, '/');
 
diff --git a/tests/system/Commands/Encryption/GenerateKeyTest.php b/tests/system/Commands/Encryption/GenerateKeyTest.php
index a4fb452fd5a2..bea6d21b4074 100644
--- a/tests/system/Commands/Encryption/GenerateKeyTest.php
+++ b/tests/system/Commands/Encryption/GenerateKeyTest.php
@@ -13,10 +13,12 @@
 
 namespace CodeIgniter\Commands\Encryption;
 
+use CodeIgniter\CLI\CLI;
 use CodeIgniter\Config\Services;
 use CodeIgniter\Superglobals;
 use CodeIgniter\Test\CIUnitTestCase;
 use CodeIgniter\Test\Filters\CITestStreamFilter;
+use CodeIgniter\Test\Mock\MockInputOutput;
 use CodeIgniter\Test\StreamFilterTrait;
 use PHPUnit\Framework\Attributes\Group;
 use PHPUnit\Framework\Attributes\PreserveGlobalState;
@@ -39,6 +41,7 @@ protected function setUp(): void
     {
         parent::setUp();
 
+        CLI::resetLastWrite();
         Services::injectMock('superglobals', new Superglobals());
 
         $this->envPath       = ROOTPATH . '.env';
@@ -62,6 +65,9 @@ protected function tearDown(): void
         }
 
         $this->resetEnvironment();
+
+        CLI::resetLastWrite();
+        CLI::reset();
     }
 
     /**
@@ -169,4 +175,98 @@ public function testKeyGenerateWhenNewBase64KeyIsSubsequentlyCommentedOut(): voi
         $this->assertStringContainsString('was successfully set.', $this->getBuffer());
         $this->assertNotSame($key, env('encryption.key', $key), 'Failed replacing the commented out key.');
     }
+
+    /**
+     * Simulates a stale env cache: the `.env` file has a valid key, but
+     * `env('encryption.key')` resolves to '' because nothing has loaded it
+     * into the superglobals. The primary regex (built from `oldKey`) cannot
+     * locate the line, so the fallback regex must replace the existing entry.
+     */
+    public function testKeyGenerateReplacesUnloadedKeyInDotEnvFile(): void
+    {
+        $existingKey = 'hex2bin:' . str_repeat('a', 64);
+        file_put_contents($this->envPath, "encryption.key = {$existingKey}\n");
+
+        $this->assertSame('', env('encryption.key', ''));
+
+        command('key:generate --force');
+
+        $this->assertStringContainsString('was successfully set.', $this->getBuffer());
+
+        $contents = (string) file_get_contents($this->envPath);
+        $this->assertStringNotContainsString($existingKey, $contents);
+        $this->assertStringContainsString('encryption.key = ' . env('encryption.key'), $contents);
+    }
+
+    public function testKeyGenerateAbortsWhenOverwritePromptIsDeclined(): void
+    {
+        command('key:generate');
+        $key = env('encryption.key', '');
+        $this->assertNotSame('', $key);
+
+        $io = new MockInputOutput();
+        $io->setInputs(['n']);
+        CLI::setInputOutput($io);
+
+        command('key:generate');
+
+        $this->assertSame($key, env('encryption.key', ''), 'Existing key should not change.');
+        $this->assertStringContainsString($key, (string) file_get_contents($this->envPath));
+        $this->assertStringContainsString('Overwrite existing key?', $io->getOutput());
+        $this->assertStringContainsString('Setting new encryption key aborted.', $io->getOutput());
+    }
+
+    public function testKeyGenerateOverwritesWhenOverwritePromptIsConfirmed(): void
+    {
+        command('key:generate');
+        $oldKey = env('encryption.key', '');
+        $this->assertNotSame('', $oldKey);
+
+        $io = new MockInputOutput();
+        $io->setInputs(['y']);
+        CLI::setInputOutput($io);
+
+        command('key:generate --prefix base64');
+
+        $this->assertNotSame($oldKey, env('encryption.key', $oldKey));
+        $this->assertStringContainsString('base64:', (string) file_get_contents($this->envPath));
+        $this->assertStringContainsString('Overwrite existing key?', $io->getOutput());
+        $this->assertStringContainsString('successfully set.', $io->getOutput());
+    }
+
+    #[PreserveGlobalState(false)]
+    #[RunInSeparateProcess]
+    public function testKeyGenerateAbortsNonInteractivelyWithExistingKey(): void
+    {
+        command('key:generate');
+        $key = env('encryption.key', '');
+        $this->assertNotSame('', $key);
+
+        $this->resetStreamFilterBuffer();
+
+        command('key:generate --no-interaction');
+
+        $this->assertSame($key, env('encryption.key', ''), 'Existing key should not change.');
+        $this->assertStringContainsString('Setting new encryption key aborted.', $this->getBuffer());
+        $this->assertStringContainsString('--force', $this->getBuffer());
+    }
+
+    public function testKeyGenerateErrorsOnInvalidPrefixNonInteractively(): void
+    {
+        command('key:generate --prefix invalid --show --no-interaction');
+
+        $this->assertStringContainsString('Invalid prefix "invalid"', $this->getBuffer());
+    }
+
+    public function testKeyGeneratePromptsForInvalidPrefix(): void
+    {
+        $io = new MockInputOutput();
+        $io->setInputs(['hex2bin']);
+        CLI::setInputOutput($io);
+
+        command('key:generate --prefix invalid --show');
+
+        $this->assertStringContainsString('Please provide a valid prefix to use.', $io->getOutput());
+        $this->assertStringContainsString('hex2bin:', $io->getOutput());
+    }
 }