[#2302] Added support for prompts schema to make the installer AI-friendly.

.vortex/installer/src/Command/InstallCommand.php

@@ -14,6 +14,8 @@
 use DrevOps\VortexInstaller\Runner\ExecutableFinderAwareInterface;
 use DrevOps\VortexInstaller\Runner\ExecutableFinderAwareTrait;
 use DrevOps\VortexInstaller\Runner\RunnerInterface;
+use DrevOps\VortexInstaller\Schema\ConfigValidator;
+use DrevOps\VortexInstaller\Schema\SchemaGenerator;
 use DrevOps\VortexInstaller\Task\Task;
 use DrevOps\VortexInstaller\Utils\Config;
 use DrevOps\VortexInstaller\Utils\Env;
@@ -53,6 +55,12 @@ class InstallCommand extends Command implements CommandRunnerAwareInterface, Exe
 
   const OPTION_BUILD = 'build';
 
+  const OPTION_SCHEMA = 'schema';
+
+  const OPTION_VALIDATE = 'validate';
+
+  const OPTION_AGENT_HELP = 'agent-help';
+
   const BUILD_RESULT_SUCCESS = 'success';
 
   const BUILD_RESULT_SKIPPED = 'skipped';
@@ -127,6 +135,9 @@ protected function configure(): void {
     $this->addOption(static::OPTION_URI, 'l', InputOption::VALUE_REQUIRED, 'Remote or local repository URI with an optional git ref set after @.');
     $this->addOption(static::OPTION_NO_CLEANUP, NULL, InputOption::VALUE_NONE, 'Do not remove installer after successful installation.');
     $this->addOption(static::OPTION_BUILD, 'b', InputOption::VALUE_NONE, 'Run auto-build after installation without prompting.');
+    $this->addOption(static::OPTION_SCHEMA, NULL, InputOption::VALUE_NONE, 'Output prompt schema as JSON.');
+    $this->addOption(static::OPTION_VALIDATE, NULL, InputOption::VALUE_NONE, 'Validate config without installing.');
+    $this->addOption(static::OPTION_AGENT_HELP, NULL, InputOption::VALUE_NONE, 'Output instructions for AI agents on how to use the installer.');
   }
 
   /**
@@ -139,6 +150,18 @@ protected function execute(InputInterface $input, OutputInterface $output): int
       return Command::SUCCESS;
     }
 
+    if ($input->getOption(static::OPTION_AGENT_HELP)) {
+      return $this->handleAgentHelp($output);
+    }
+
+    if ($input->getOption(static::OPTION_SCHEMA)) {
+      return $this->handleSchema($input, $output);
+    }
+
+    if ($input->getOption(static::OPTION_VALIDATE)) {
+      return $this->handleValidate($input, $output);
+    }
+
     Tui::init($output);
 
     try {
@@ -266,6 +289,162 @@ protected function execute(InputInterface $input, OutputInterface $output): int
     return Command::SUCCESS;
   }
 
+  /**
+   * Handle --schema option.
+   */
+  protected function handleSchema(InputInterface $input, OutputInterface $output): int {
+    $config = Config::fromString('{}');
+    $prompt_manager = new PromptManager($config);
+
+    $generator = new SchemaGenerator();
+    $schema = $generator->generate($prompt_manager->getHandlers());
+
+    $output->write((string) json_encode($schema, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+
+    return Command::SUCCESS;
+  }
+
+  /**
+   * Handle --validate option.
+   */
+  protected function handleValidate(InputInterface $input, OutputInterface $output): int {
+    $config_option = $input->getOption(static::OPTION_CONFIG);
+
+    if (empty($config_option) || !is_string($config_option)) {
+      $output->writeln('The --validate option requires --config.');
+
+      return Command::FAILURE;
+    }
+
+    $config_json = is_file($config_option) ? (string) file_get_contents($config_option) : $config_option;
+    $user_config = json_decode($config_json, TRUE);
+
+    if (!is_array($user_config)) {
+      $output->writeln('Invalid JSON in --config.');
+
+      return Command::FAILURE;
+    }
+
+    $config = Config::fromString('{}');
+    $prompt_manager = new PromptManager($config);
+
+    $validator = new ConfigValidator();
+    $result = $validator->validate($user_config, $prompt_manager->getHandlers());
+
+    $output->write((string) json_encode($result, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
+
+    return $result['valid'] ? Command::SUCCESS : Command::FAILURE;
+  }
+
+  /**
+   * Handle --agent-help option.
+   *
+   * Outputs instructions for AI agents on how to use the installer
+   * programmatically via --schema and --validate.
+   */
+  protected function handleAgentHelp(OutputInterface $output): int {
+    $text = <<<'AGENT_HELP'
+# Vortex Installer - AI Agent Instructions
+
+You are interacting with the Vortex installer, a CLI tool that sets up Drupal
+projects from the Vortex template. This guide explains how to use the installer
+programmatically.
+
+## Workflow
+
+1. **Discover prompts**: Run with `--schema` to get a JSON manifest of all
+   available configuration prompts, their types, valid values, defaults, and
+   dependencies.
+
+2. **Build a config**: Using the schema, construct a JSON object where keys are
+   either prompt IDs (e.g., `hosting_provider`) or environment variable names
+   (e.g., `VORTEX_INSTALLER_PROMPT_HOSTING_PROVIDER`). Set values according to
+   the prompt types and allowed options from the schema.
+
+3. **Validate the config**: Run with `--validate --config='<json>'` to check
+   your config without performing an installation. The output is a JSON object
+   with `valid`, `errors`, `warnings`, and `resolved` fields.
+
+4. **Install**: Run with `--no-interaction --config='<json>' --destination=<dir>`
+   to perform the actual installation using your validated config.
+
+## Commands
+
+```bash
+# Get the prompt schema
+php installer.php --schema
+
+# Validate a config (JSON string)
+php installer.php --validate --config='{"name":"My Project","hosting_provider":"lagoon"}'
+
+# Validate a config (JSON file)
+php installer.php --validate --config=config.json
+
+# Install non-interactively
+php installer.php --no-interaction --config='<json>' --destination=./my-project
+```
+
+## Schema Format
+
+The `--schema` output contains a `prompts` array. Each prompt has:
+
+- `id`: The prompt identifier (use as config key).
+- `env`: The environment variable name (alternative config key).
+- `type`: One of `text`, `select`, `multiselect`, `confirm`, `suggest`.
+- `label`: Human-readable label.
+- `description`: Optional description text.
+- `options`: For `select`/`multiselect`, an array of `{value, label}` objects
+  representing the allowed values.
+- `default`: The default value if not provided.
+- `required`: Whether the prompt requires a value.
+- `depends_on`: Dependency conditions. If set, this prompt only applies when
+  the referenced prompt has one of the specified values. A `_system` key
+  indicates a system-state dependency (not config-based).
+
+## Value Types by Prompt Type
+
+- `text` / `suggest`: string value.
+- `select`: string value matching one of the option values.
+- `multiselect`: array of strings, each matching an option value.
+- `confirm`: boolean (`true` or `false`).
+
+## Dependencies
+
+Some prompts depend on other prompts. For example, `hosting_project_name`
+depends on `hosting_provider` being `lagoon` or `acquia`. If you set
+`hosting_provider` to `none`, you do not need to provide `hosting_project_name`.
+
+When a dependency is not met:
+- Omitting the dependent value is OK (it will be skipped).
+- Providing a value triggers a warning (it will be ignored).
+
+When a dependency is met:
+- Required prompts must have a value or they produce an error.
+
+## Validation Output
+
+The `--validate` output contains:
+
+- `valid`: boolean - whether the config is valid.
+- `errors`: array of `{prompt, message}` objects for invalid values.
+- `warnings`: array of `{prompt, message}` objects for ignored values.
+- `resolved`: object with the final merged config (your values + defaults).
+
+## Tips
+
+- Start with `--schema` to understand what prompts exist.
+- Provide values only for prompts you want to customize; defaults will be
+  used for the rest.
+- Use `--validate` to check your config before installing.
+- The `resolved` field in validation output shows the complete config that
+  would be used, including defaults.
+AGENT_HELP;
+
+    $output->write($text);
+
+    return Command::SUCCESS;
+  }
+
   protected function checkRequirements(): void {
     $required_commands = [
       'git',

.vortex/installer/src/Prompts/Handlers/AbstractHandler.php

@@ -4,6 +4,7 @@
 
 namespace DrevOps\VortexInstaller\Prompts\Handlers;
 
+use DrevOps\VortexInstaller\Prompts\PromptType;
 use DrevOps\VortexInstaller\Utils\Config;
 use DrevOps\VortexInstaller\Utils\Converter;
 
@@ -61,6 +62,49 @@ public static function id(): string {
     return Converter::machine(Converter::pascal2snake(str_replace('Handler', '', basename($filename, '.php'))));
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public static function envName(): string {
+    return Converter::constant('VORTEX_INSTALLER_PROMPT_' . static::id());
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function type(): PromptType {
+    $options = $this->options([]);
+
+    if (is_array($options)) {
+      if (array_is_list($options)) {
+        return PromptType::Suggest;
+      }
+
+      $default = $this->default([]);
+
+      if (is_array($default)) {
+        return PromptType::MultiSelect;
+      }
+
+      return PromptType::Select;
+    }
+
+    $default = $this->default([]);
+
+    if (is_bool($default)) {
+      return PromptType::Confirm;
+    }
+
+    return PromptType::Text;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function dependsOn(): ?array {
+    return NULL;
+  }
+
   /**
    * {@inheritdoc}
    */

.vortex/installer/src/Prompts/Handlers/DatabaseDownloadSource.php

@@ -64,6 +64,13 @@ public function options(array $responses): ?array {
     return $options;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function dependsOn(): ?array {
+    return [ProvisionType::id() => [ProvisionType::DATABASE]];
+  }
+
   /**
    * {@inheritdoc}
    */

.vortex/installer/src/Prompts/Handlers/DatabaseImage.php

@@ -40,6 +40,13 @@ public function placeholder(array $responses): ?string {
     return parent::placeholder($responses);
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function dependsOn(): ?array {
+    return [DatabaseDownloadSource::id() => [DatabaseDownloadSource::CONTAINER_REGISTRY]];
+  }
+
   /**
    * {@inheritdoc}
    */

.vortex/installer/src/Prompts/Handlers/HandlerInterface.php

@@ -4,6 +4,8 @@
 
 namespace DrevOps\VortexInstaller\Prompts\Handlers;
 
+use DrevOps\VortexInstaller\Prompts\PromptType;
+
 /**
  * Interface HandlerInterface.
  *
@@ -13,11 +15,49 @@
  */
 interface HandlerInterface {
 
+  /**
+   * Reserved dependency key for system-state conditions.
+   */
+  const DEPENDS_ON_SYSTEM = '_system';
+
+  /**
+   * Reserved dependency value for fresh install condition.
+   */
+  const DEPENDS_ON_FRESH_INSTALL = '_fresh_install';
+
   /**
    * The unique identifier of the handler.
    */
   public static function id(): string;
 
+  /**
+   * Get the environment variable name for this handler.
+   *
+   * @return string
+   *   The environment variable name in the format VORTEX_INSTALLER_PROMPT_*.
+   */
+  public static function envName(): string;
+
+  /**
+   * Get the prompt type for this handler.
+   *
+   * @return \DrevOps\VortexInstaller\Prompts\PromptType
+   *   The prompt type enum case.
+   */
+  public function type(): PromptType;
+
+  /**
+   * Get dependency conditions for this handler.
+   *
+   * Returns an associative array where keys are handler IDs and values are
+   * arrays of acceptable values. The handler should only run when the
+   * dependency handler's response matches one of the acceptable values.
+   *
+   * @return array<string, array<mixed>>|null
+   *   The dependency conditions, or NULL if no dependencies.
+   */
+  public function dependsOn(): ?array;
+
   /**
    * Label for of the handler.
    *

.vortex/installer/src/Prompts/Handlers/HostingProjectName.php

@@ -38,6 +38,13 @@ public function isRequired(): bool {
     return TRUE;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function dependsOn(): ?array {
+    return [HostingProvider::id() => [HostingProvider::LAGOON, HostingProvider::ACQUIA]];
+  }
+
   /**
    * {@inheritdoc}
    */

.vortex/installer/src/Prompts/Handlers/MigrationDownloadSource.php

@@ -58,6 +58,13 @@ public function options(array $responses): ?array {
     return $options;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function dependsOn(): ?array {
+    return [Migration::id() => [TRUE]];
+  }
+
   /**
    * {@inheritdoc}
    */