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<?php |
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|
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namespace FluentCart\App\Modules\MCP; |
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|
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use FluentCart\App\Modules\MCP\Tools\ContextTools; |
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use FluentCart\App\Modules\MCP\Tools\SearchTools; |
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use FluentCart\App\Modules\MCP\Tools\OrderTools; |
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use FluentCart\App\Modules\MCP\Tools\CustomerTools; |
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use FluentCart\App\Modules\MCP\Tools\ProductTools; |
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use FluentCart\App\Modules\MCP\Tools\SubscriptionTools; |
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use FluentCart\App\Modules\MCP\Tools\CouponTools; |
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use FluentCart\App\Modules\MCP\Tools\LabelTools; |
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use FluentCart\App\Modules\MCP\Tools\ReportTools; |
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use FluentCart\App\Modules\MCP\Tools\ProductFinancialsTools; |
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use FluentCart\App\Modules\MCP\Tools\PaymentScheduleTools; |
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use FluentCart\App\Modules\MCP\Tools\TransactionTools; |
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|
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/** |
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* Single source of truth for every FluentCart MCP ability. |
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* |
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* Each tool class owns its own `definitions()` slice (schema next to code); |
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* this class merges them, wraps every execute_callback — rejecting undeclared |
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* input params up front and converting unhandled exceptions into structured |
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* WP_Errors the agent can read (instead of the adapter's generic "Tool |
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* execution failed") — and registers each as a WP ability. |
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* |
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* Pro tools are NOT listed here — FluentCart Pro pushes its abilities via the |
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* `fluent_cart/mcp_loaded` action + `fluent_cart/mcp_ability_names` filter. |
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*/ |
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class AbilitiesRegistrar |
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{ |
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/** Tool classes that expose a static definitions() method. */ |
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private static function toolClasses() |
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{ |
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return [ |
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ContextTools::class, |
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SearchTools::class, |
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OrderTools::class, |
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CustomerTools::class, |
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ProductTools::class, |
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SubscriptionTools::class, |
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CouponTools::class, |
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LabelTools::class, |
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ReportTools::class, |
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ProductFinancialsTools::class, |
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PaymentScheduleTools::class, |
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TransactionTools::class, |
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]; |
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} |
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|
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public static function getDefinitions() |
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{ |
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$defs = []; |
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|
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foreach (self::toolClasses() as $class) { |
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if (class_exists($class) && method_exists($class, 'definitions')) { |
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$defs = array_merge($defs, (array) $class::definitions()); |
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} |
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} |
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|
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return $defs; |
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} |
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|
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public static function register() |
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{ |
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foreach (self::getDefinitions() as $name => $definition) { |
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try { |
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self::registerAbility($name, $definition); |
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} catch (\Throwable $e) { |
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// Registration runs on wp_abilities_api_init, which the adapter |
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// fires lazily from INSIDE our own create_server() call — so an |
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// uncaught throw here doesn't just drop this one ability: it |
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// aborts every later callback on the action (other plugins' |
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// abilities included) and kills the FluentCart MCP server |
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// itself, 404ing the endpoint. One malformed definition must |
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// never take the whole surface down: skip it, log it, move on. |
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fluent_cart_error_log( |
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'MCP ability registration failed: ' . $name, |
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get_class($e) . ': ' . $e->getMessage() . ' at ' . basename($e->getFile()) . ':' . $e->getLine() |
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); |
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|
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/** |
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* Fires when a single MCP ability fails to register. The |
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* remaining abilities still register; this lets sites alert on |
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* the gap. |
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* |
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* @since 1.0.0 |
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* |
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* @param array $context { exception: \Throwable, ability: string } |
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*/ |
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do_action('fluent_cart/mcp_ability_registration_failed', [ |
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'exception' => $e, |
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'ability' => $name, |
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]); |
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} |
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} |
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} |
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|
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/** |
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* Register one ability definition with the Abilities API. Kept separate |
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* from register() so its try/catch stays a thin skip-and-continue shell. |
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*/ |
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private static function registerAbility($name, $definition) |
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{ |
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// Cast before array_keys: no-arg tools declare properties as |
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// stdClass (so the schema serializes as {} not []), which |
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// array_keys() rejects on PHP 8 with a TypeError. |
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$declaredParams = isset($definition['input_schema']['properties']) |
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? array_keys((array) $definition['input_schema']['properties']) |
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: []; |
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|
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$args = [ |
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'label' => $definition['label'], |
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'description' => $definition['description'], |
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'category' => 'fluent-cart', |
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'execute_callback' => self::wrapExecuteCallback($name, $definition['execute_callback'], $declaredParams), |
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'permission_callback' => $definition['permission_callback'], |
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'meta' => [ |
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'show_in_rest' => true, |
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'mcp' => ['public' => true], |
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], |
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]; |
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|
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if (!empty($definition['input_schema'])) { |
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$args['input_schema'] = $definition['input_schema']; |
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} |
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|
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if (!empty($definition['output_schema'])) { |
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$args['output_schema'] = $definition['output_schema']; |
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} |
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|
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if (!empty($definition['annotations'])) { |
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$mapped = self::mapAnnotations($definition['annotations']); |
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if (!empty($mapped)) { |
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$args['meta']['annotations'] = $mapped; |
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} |
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} |
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|
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wp_register_ability($name, $args); |
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} |
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|
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/** |
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* Translate a tool's readable snake_case behavior hints into the MCP tool |
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* annotation keys clients actually read. |
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* |
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* Tool classes declare intent as readonly / destructive / idempotent / |
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* open_world / title. The MCP spec names them readOnlyHint / destructiveHint |
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* / idempotentHint / openWorldHint, and the WP MCP adapter forwards |
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* meta.annotations VERBATIM (it does not translate), so an unmapped |
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* 'readonly' key would never reach a client as a real hint. Unknown keys |
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* (e.g. a stray 'bulk') are dropped rather than emitted as noise a client |
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* cannot act on. |
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* |
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* @param array $annotations snake_case behavior hints from the tool definition |
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* @return array MCP-standard annotation keys |
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*/ |
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private static function mapAnnotations($annotations) |
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{ |
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$map = [ |
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'readonly' => 'readOnlyHint', |
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'destructive' => 'destructiveHint', |
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'idempotent' => 'idempotentHint', |
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'open_world' => 'openWorldHint', |
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]; |
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|
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$out = []; |
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foreach ((array) $annotations as $key => $value) { |
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if ($key === 'title') { |
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$out['title'] = (string) $value; |
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} elseif (isset($map[$key])) { |
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$out[$map[$key]] = (bool) $value; |
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} |
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} |
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|
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// A read-only tool cannot be destructive. destructiveHint defaults to |
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// true when absent (MCP spec), so state it explicitly for read tools — |
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// otherwise a client gating on destructiveHint would treat every report |
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// as dangerous. |
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if (!empty($out['readOnlyHint']) && !isset($out['destructiveHint'])) { |
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$out['destructiveHint'] = false; |
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} |
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|
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return $out; |
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} |
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|
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/** |
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* Reject any input param this tool does not declare, instead of executing |
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* with it silently dropped. input_schema sets no additionalProperties, so an |
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* unknown key would otherwise pass validation and the agent would get a |
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* full, plausible-looking result that is NOT filtered the way it asked — |
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* the worst failure mode for an agent (a wrong number reads as a right one; |
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* an error is recoverable). Sibling tools also name overlapping concepts |
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* differently (list-orders: created_after/type; query-orders: start_date/ |
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* order_type dimension), so carried-over names are a common, realistic slip, |
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* not a rare typo. The error lists the accepted params so the agent can |
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* self-correct in one step — richer than the schema validator's message, |
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* which is why this is enforced here rather than via additionalProperties. |
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* |
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* @param string $toolName |
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* @param mixed $params the raw input params |
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* @param array $declaredParams input_schema property names this tool declares |
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* @return \WP_Error|null null when all params are declared |
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*/ |
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private static function rejectUnknownParams($toolName, $params, $declaredParams) |
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{ |
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if (!is_array($params)) { |
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return null; |
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} |
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|
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$unknown = []; |
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foreach (array_keys($params) as $key) { |
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if (!in_array((string) $key, $declaredParams, true)) { |
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$unknown[] = (string) $key; |
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} |
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} |
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|
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if (empty($unknown)) { |
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return null; |
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} |
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|
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return \FluentCart\App\Modules\MCP\Support\MCPHelper::error( |
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'unknown_param', |
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sprintf( |
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/* translators: 1: rejected parameter names, 2: tool name, 3: accepted parameter names */ |
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__('Unknown parameter(s) [%1$s] — %2$s does not support them, and running without them would return a result that is NOT filtered the way you asked. Accepted parameters: [%3$s]. Rename or remove the unknown parameter(s) and retry.', 'fluent-cart'), |
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implode(', ', $unknown), |
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$toolName, |
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$declaredParams ? implode(', ', $declaredParams) : __('none — this tool takes no parameters', 'fluent-cart') |
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), |
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['fields' => $unknown, 'accepted' => $declaredParams, 'tool' => $toolName] |
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); |
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} |
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|
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/** |
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* Append a meta.warnings entry when a requested per_page exceeded the tool's |
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* ceiling and was clamped (the descriptions state each cap, but a stated cap |
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* still deserves a runtime signal — the agent asked for 500 rows and must |
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* know it got a 100-row page, not the full set). Detected generically by |
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* comparing the request against meta.page.per_page, so every list and |
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* query tool is covered without per-tool changes. Untouched when the result |
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* isn't a paged success envelope. |
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* |
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* @param mixed $result the tool's return value |
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* @param mixed $params the raw input params |
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* @return mixed |
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*/ |
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private static function annotateClampedPerPage($result, $params) |
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{ |
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if ( |
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!is_array($params) || !isset($params['per_page']) |
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|| !is_array($result) || !isset($result['meta']['page']['per_page']) |
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) { |
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return $result; |
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} |
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|
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$requested = (int) $params['per_page']; |
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$actual = (int) $result['meta']['page']['per_page']; |
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if ($actual < 1 || $requested <= $actual) { |
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return $result; |
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} |
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|
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$warnings = (isset($result['meta']['warnings']) && is_array($result['meta']['warnings'])) |
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? $result['meta']['warnings'] |
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: []; |
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|
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$warnings[] = sprintf( |
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/* translators: 1: requested per_page, 2: the maximum this tool returned */ |
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__('per_page %1$d exceeds this tool\'s maximum; %2$d rows per page were returned. Use meta.page (total/pages/has_more) to page through the rest.', 'fluent-cart'), |
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$requested, |
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$actual |
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); |
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|
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$result['meta']['warnings'] = $warnings; |
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|
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return $result; |
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} |
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|
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/** |
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* Convert any unhandled \Throwable from a tool into a structured WP_Error |
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* carrying the real message (and, under WP_DEBUG, the file + a short trace). |
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* Without this the agent only sees the adapter's generic failure surface and |
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* retries blindly against tools that may have partially succeeded. |
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*/ |
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private static function wrapExecuteCallback($toolName, $callback, $declaredParams = []) |
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{ |
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return function ($params) use ($toolName, $callback, $declaredParams) { |
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try { |
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// Before executing: an undeclared param means the caller asked for |
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// a filter this tool can't apply — error out rather than return a |
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// confidently wrong (unfiltered) result. Runs before the callback |
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// so write tools never partially execute on a malformed call. |
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$unknownError = self::rejectUnknownParams($toolName, $params, $declaredParams); |
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if ($unknownError !== null) { |
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return $unknownError; |
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} |
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|
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$result = call_user_func($callback, $params); |
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return self::annotateClampedPerPage($result, $params); |
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} catch (\Throwable $e) { |
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/** |
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* Fires when an MCP tool throws. Lets sites log/alert before the |
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* structured error reaches the agent. |
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* |
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* @since 1.0.0 |
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* |
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* @param array $context { exception: \Throwable, tool: string, params: mixed } |
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*/ |
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do_action('fluent_cart/mcp_tool_exception', [ |
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'exception' => $e, |
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'tool' => $toolName, |
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'params' => $params, |
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]); |
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|
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// Unexpected exceptions are treated as transient (retryable): |
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// the agent may legitimately retry once. |
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$details = ['tool' => $toolName, 'exception' => get_class($e), 'retryable' => true]; |
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|
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// File/line/trace help an operator debug, but this payload is |
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// forwarded to the remote agent/LLM — raw paths would leak the |
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// server's filesystem layout. So it's off by default and opt-in |
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// only; full detail is always available server-side via the |
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// action above. When enabled, the file is reduced to a basename. |
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$exposeDetails = apply_filters('fluent_cart/mcp_expose_error_details', false); |
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if ($exposeDetails) { |
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$details['file'] = basename($e->getFile()) . ':' . $e->getLine(); |
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$details['trace'] = array_slice(explode("\n", $e->getTraceAsString()), 0, 5); |
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} |
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|
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return \FluentCart\App\Modules\MCP\Support\MCPHelper::error('tool_failed', $e->getMessage(), $details); |
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} |
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}; |
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} |
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} |
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|
