feat: configurable exposure policy for direct, indirect and disabled tools

Introduces ExposurePolicy (option lit_mcp_exposure) deciding per ability
whether it is a direct MCP tool, only reachable via mcp-adapter's
execute-ability meta-tool, or disabled entirely (not registered with the
Abilities API at all). Ability::isDirect() remains the default when no
override applies. lit/guide can never be disabled or made indirect;
lit/media-preview and lit/media-download (image/embedded-resource results)
can never be made indirect, only direct or disabled.

AbilityRegistrar and ServerRegistrar take an optional ExposurePolicy and
use it to filter registered abilities / compute the direct tool list.
IntegrationRegistry::directAbilityNames() is removed (superseded by
ExposurePolicy::directNames()). InstructionsBuilder now also takes the
policy and lists the currently direct tools by name (lit-<name>), noting
the rest are reachable via mcp-adapter-execute-ability as lit/<name>.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

src/Abilities/AbilityRegistrar.php

@@ -18,7 +18,7 @@ final class AbilityRegistrar
 {
     public const CATEGORY = 'lit-mcp';
 
-    public function __construct(private IntegrationRegistry $registry)
+    public function __construct(private IntegrationRegistry $registry, private ?ExposurePolicy $policy = null)
     {
     }
 
@@ -38,7 +38,8 @@ final class AbilityRegistrar
 
     public function registerAbilities(): void
     {
-        foreach ($this->registry->abilities() as $ability) {
+        $policy = $this->policy ?? new ExposurePolicy();
+        foreach ($policy->enabled($this->registry->abilities()) as $ability) {
             wp_register_ability($ability->name(), $this->argsFor($ability));
         }
     }

src/Abilities/ExposurePolicy.php

@@ -0,0 +1,122 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Abilities;
+
+/**
+ * Decides per ability whether it is a direct MCP tool, only reachable through the
+ * adapter's meta-tools, or disabled (spec §4.3). Ability::isDirect() is the default.
+ */
+final class ExposurePolicy
+{
+    public const OPTION = 'lit_mcp_exposure';
+    public const DIRECT = 'direct';
+    public const INDIRECT = 'indirect';
+    public const DISABLED = 'disabled';
+    public const MODES = [self::DIRECT, self::INDIRECT, self::DISABLED];
+
+    /**
+     * Image/embedded-resource results only work for direct tools (ruling Q6 / task 6
+     * dispatch): lit/media-preview (ImageContent) and lit/media-download (embedded
+     * resource) can be direct or disabled, but never indirect.
+     */
+    public const DIRECT_ONLY = ['lit/media-preview', 'lit/media-download'];
+
+    /** Entry point for every conversation – must always stay a direct tool. */
+    public const REQUIRED = ['lit/guide'];
+
+    /** @param array<string, string> $overrides Ability name => mode. */
+    public function __construct(private array $overrides = [])
+    {
+    }
+
+    public static function fromOption(): self
+    {
+        return new self(self::sanitize(get_option(self::OPTION, [])));
+    }
+
+    public function mode(Ability $ability): string
+    {
+        $mode = $this->overrides[$ability->name()] ?? null;
+
+        return is_string($mode) && self::isAllowed($ability->name(), $mode) ? $mode : $this->defaultMode($ability);
+    }
+
+    public function defaultMode(Ability $ability): string
+    {
+        return $ability->isDirect() ? self::DIRECT : self::INDIRECT;
+    }
+
+    /**
+     * @param list<Ability> $abilities
+     * @return list<Ability>
+     */
+    public function enabled(array $abilities): array
+    {
+        return array_values(array_filter(
+            $abilities,
+            fn (Ability $ability): bool => $this->mode($ability) !== self::DISABLED
+        ));
+    }
+
+    /**
+     * @param list<Ability> $abilities
+     * @return list<string>
+     */
+    public function directNames(array $abilities): array
+    {
+        $names = [];
+        foreach ($abilities as $ability) {
+            if ($this->mode($ability) === self::DIRECT) {
+                $names[] = $ability->name();
+            }
+        }
+
+        return $names;
+    }
+
+    public static function isAllowed(string $name, string $mode): bool
+    {
+        if (! in_array($mode, self::MODES, true)) {
+            return false;
+        }
+
+        if (in_array($name, self::REQUIRED, true)) {
+            return $mode === self::DIRECT;
+        }
+
+        if (in_array($name, self::DIRECT_ONLY, true)) {
+            return $mode !== self::INDIRECT;
+        }
+
+        return true;
+    }
+
+    /**
+     * Settings API sanitize callback for the option.
+     *
+     * @return array<string, string>
+     */
+    public static function sanitize(mixed $input): array
+    {
+        if (! is_array($input)) {
+            return [];
+        }
+
+        $clean = [];
+        foreach ($input as $name => $mode) {
+            if (
+                is_string($name)
+                && is_string($mode)
+                && preg_match('#^[a-z0-9-]+/[a-z0-9-]+$#', $name) === 1
+                && self::isAllowed($name, $mode)
+            ) {
+                $clean[$name] = $mode;
+            }
+        }
+        ksort($clean);
+
+        return $clean;
+    }
+}

src/Guides/InstructionsBuilder.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Guides;
 
+use LIT\MCP\Abilities\ExposurePolicy;
 use LIT\MCP\Integrations\Integration;
 use LIT\MCP\Integrations\IntegrationRegistry;
 
@@ -16,9 +17,15 @@ final class InstructionsBuilder
     /** @var (callable(): list<string>)|null */
     private $postTypeNames;
 
-    public function __construct(private IntegrationRegistry $registry, ?callable $postTypeNames = null)
-    {
+    private ExposurePolicy $policy;
+
+    public function __construct(
+        private IntegrationRegistry $registry,
+        ?callable $postTypeNames = null,
+        ?ExposurePolicy $policy = null
+    ) {
         $this->postTypeNames = $postTypeNames;
+        $this->policy = $policy ?? new ExposurePolicy();
     }
 
     public function build(): string
@@ -28,9 +35,16 @@ final class InstructionsBuilder
             $this->registry->available()
         ));
 
+        $directNames = array_map(
+            static fn (string $name): string => 'lit-' . substr($name, strlen('lit/')),
+            $this->policy->directNames($this->registry->abilities())
+        );
+
         $lines = [
             'LIT MCP pflegt diese WordPress-Website (Inhalte, Medien, Divi 5, Pods).',
             'Aktive Integrationen: ' . $active . '.',
+            'Direkt aufrufbare Tools: ' . implode(', ', $directNames) . '.',
+            'Weitere Fähigkeiten über mcp-adapter-execute-ability (Ability-Name lit/<name>).',
         ];
 
         if ($this->postTypeNames !== null) {

src/Integrations/IntegrationRegistry.php

@@ -42,17 +42,4 @@ final class IntegrationRegistry
 
         return $this->abilities;
     }
-
-    /** @return list<string> */
-    public function directAbilityNames(): array
-    {
-        $names = [];
-        foreach ($this->abilities() as $ability) {
-            if ($ability->isDirect()) {
-                $names[] = $ability->name();
-            }
-        }
-
-        return $names;
-    }
 }

src/Plugin.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace LIT\MCP;
 
 use LIT\MCP\Abilities\AbilityRegistrar;
+use LIT\MCP\Abilities\ExposurePolicy;
 use LIT\MCP\ChangeLog\ChangeLog;
 use LIT\MCP\ChangeLog\ChangeLogCleanup;
 use LIT\MCP\ChangeLog\ChangeLogInstaller;
@@ -54,10 +55,15 @@ final class Plugin
             new MediaIntegration($schema, $changeLog, $limits)
         );
 
-        (new AbilityRegistrar($registry))->register();
+        $policy = ExposurePolicy::fromOption();
+        (new AbilityRegistrar($registry, $policy))->register();
         (new ServerRegistrar(
             $registry,
-            new InstructionsBuilder($registry, static fn (): array => $schema->postTypeNames())
+            new InstructionsBuilder($registry, static fn (): array => $schema->postTypeNames(), $policy),
+            null,
+            null,
+            null,
+            $policy
         ))->register();
 
         \WPMedia\MCP\OAuth\Bootstrap::instance();

src/Server/ServerRegistrar.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace LIT\MCP\Server;
 
+use LIT\MCP\Abilities\ExposurePolicy;
 use LIT\MCP\Guides\InstructionsBuilder;
 use LIT\MCP\Integrations\IntegrationRegistry;
 use LIT\MCP\Plugin;
@@ -48,13 +49,17 @@ final class ServerRegistrar
     /** @var callable(string): bool */
     private $classExists;
 
+    private ExposurePolicy $policy;
+
     public function __construct(
         private IntegrationRegistry $registry,
         private InstructionsBuilder $instructions,
         ?callable $oauthEnabled = null,
         ?callable $createAdapterServer = null,
-        ?callable $classExists = null
+        ?callable $classExists = null,
+        ?ExposurePolicy $policy = null
     ) {
+        $this->policy = $policy ?? new ExposurePolicy();
         $this->oauthEnabled = $oauthEnabled
             ?? static fn (): bool => (new OAuthContext())->is_enabled();
         $this->classExists = $classExists
@@ -102,7 +107,7 @@ final class ServerRegistrar
             'name' => 'LIT MCP',
             'description' => $this->instructions->build(),
             'version' => Plugin::VERSION,
-            'tools' => array_merge($this->registry->directAbilityNames(), self::META_TOOLS),
+            'tools' => array_merge($this->policy->directNames($this->registry->abilities()), self::META_TOOLS),
         ];
     }