feat: remove dependency on llm-chain (#13)

Author: Nyholm

composer.json

@@ -12,8 +12,7 @@
     "require": {
         "php": "^8.2",
         "psr/log": "^3.0",
-        "symfony/uid": "^6.4 || ^7.0",
-        "php-llm/llm-chain": "^0.19.0"
+        "symfony/uid": "^6.4 || ^7.0"
     },
     "require-dev": {
         "php-cs-fixer/shim": "^3.70",

src/Capability/Tool/MetadataInterface.php

@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpSdk\Capability\Tool;
+
+interface MetadataInterface
+{
+    public function getName(): string;
+
+    public function getDescription(): string;
+
+    public function getInputSchema(): array;
+}

src/Capability/Tool/ToolCall.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpSdk\Capability\Tool;
+
+final readonly class ToolCall implements \JsonSerializable
+{
+    /**
+     * @param array<string, mixed> $arguments
+     */
+    public function __construct(
+        public string $id,
+        public string $name,
+        public array $arguments = [],
+    ) {
+    }
+
+    /**
+     * @return array{
+     *     id: string,
+     *     type: 'function',
+     *     function: array{
+     *         name: string,
+     *         arguments: string
+     *     }
+     * }
+     */
+    public function jsonSerialize(): array
+    {
+        return [
+            'id' => $this->id,
+            'type' => 'function',
+            'function' => [
+                'name' => $this->name,
+                'arguments' => json_encode($this->arguments),
+            ],
+        ];
+    }
+}

src/Capability/Tool/ToolCollectionInterface.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace PhpLlm\McpSdk\Capability\Tool;
+
+interface ToolCollectionInterface
+{
+    /**
+     * @return MetadataInterface[]
+     */
+    public function getMetadata(): array;
+}

src/Capability/Tool/ToolExecutorInterface.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace PhpLlm\McpSdk\Capability\Tool;
+
+use PhpLlm\McpSdk\Exception\ToolExecutionException;
+use PhpLlm\McpSdk\Exception\ToolNotFoundException;
+
+interface ToolExecutorInterface
+{
+    /**
+     * @throws ToolExecutionException if the tool execution fails
+     * @throws ToolNotFoundException  if the tool is not found
+     */
+    public function execute(ToolCall $toolCall): mixed;
+}

src/Exception/ExceptionInterface.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpSdk\Exception;
+
+use PhpLlm\LlmChain\Exception\ExceptionInterface as BaseExceptionInterface;
+
+interface ExceptionInterface extends BaseExceptionInterface
+{
+}

src/Exception/ToolExecutionException.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpSdk\Exception;
+
+use PhpLlm\LlmChain\Model\Response\ToolCall;
+
+final class ToolExecutionException extends \RuntimeException implements ExceptionInterface
+{
+    public ?ToolCall $toolCall = null;
+
+    public static function executionFailed(ToolCall $toolCall, \Throwable $previous): self
+    {
+        $exception = new self(sprintf('Execution of tool "%s" failed with error: %s', $toolCall->name, $previous->getMessage()), previous: $previous);
+        $exception->toolCall = $toolCall;
+
+        return $exception;
+    }
+}

src/Exception/ToolNotFoundException.php

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpSdk\Exception;
+
+use PhpLlm\LlmChain\Chain\Toolbox\ExecutionReference;
+use PhpLlm\LlmChain\Model\Response\ToolCall;
+
+final class ToolNotFoundException extends \RuntimeException implements ExceptionInterface
+{
+    public ?ToolCall $toolCall = null;
+
+    public static function notFoundForToolCall(ToolCall $toolCall): self
+    {
+        $exception = new self(sprintf('Tool not found for call: %s.', $toolCall->name));
+        $exception->toolCall = $toolCall;
+
+        return $exception;
+    }
+
+    public static function notFoundForReference(ExecutionReference $reference): self
+    {
+        return new self(sprintf('Tool not found for reference: %s::%s.', $reference->class, $reference->method));
+    }
+}

src/Server/RequestHandler/ToolCallHandler.php

@@ -4,17 +4,17 @@
 
 namespace PhpLlm\McpSdk\Server\RequestHandler;
 
-use PhpLlm\LlmChain\Chain\Toolbox\ToolboxInterface;
-use PhpLlm\LlmChain\Exception\ExceptionInterface;
-use PhpLlm\LlmChain\Model\Response\ToolCall;
+use PhpLlm\McpSdk\Capability\Tool\ToolCall;
+use PhpLlm\McpSdk\Capability\Tool\ToolExecutorInterface;
+use PhpLlm\McpSdk\Exception\ExceptionInterface;
 use PhpLlm\McpSdk\Message\Error;
 use PhpLlm\McpSdk\Message\Request;
 use PhpLlm\McpSdk\Message\Response;
 
 final class ToolCallHandler extends BaseRequestHandler
 {
     public function __construct(
-        private readonly ToolboxInterface $toolbox,
+        private readonly ToolExecutorInterface $toolbox,
     ) {
     }
 
@@ -24,7 +24,7 @@ public function createResponse(Request $message): Response|Error
         $arguments = $message->params['arguments'] ?? [];
 
         try {
-            $result = $this->toolbox->execute(new ToolCall(uniqid(), $name, $arguments));
+            $result = $this->toolbox->execute(new ToolCall(uniqid('', true), $name, $arguments));
         } catch (ExceptionInterface) {
             return Error::internalError($message->id, 'Error while executing tool');
         }

src/Server/RequestHandler/ToolListHandler.php

@@ -4,31 +4,33 @@
 
 namespace PhpLlm\McpSdk\Server\RequestHandler;
 
-use PhpLlm\LlmChain\Chain\Toolbox\Metadata;
-use PhpLlm\LlmChain\Chain\Toolbox\ToolboxInterface;
+use PhpLlm\McpSdk\Capability\Tool\MetadataInterface;
+use PhpLlm\McpSdk\Capability\Tool\ToolCollectionInterface;
 use PhpLlm\McpSdk\Message\Request;
 use PhpLlm\McpSdk\Message\Response;
 
 final class ToolListHandler extends BaseRequestHandler
 {
     public function __construct(
-        private readonly ToolboxInterface $toolbox,
+        private readonly ToolCollectionInterface $toolbox,
     ) {
     }
 
     public function createResponse(Request $message): Response
     {
         return new Response($message->id, [
-            'tools' => array_map(function (Metadata $tool) {
+            'tools' => array_map(function (MetadataInterface $tool) {
+                $inputSchema = $tool->getInputSchema();
+
                 return [
-                    'name' => $tool->name,
-                    'description' => $tool->description,
-                    'inputSchema' => $tool->parameters ?? [
+                    'name' => $tool->getName(),
+                    'description' => $tool->getDescription(),
+                    'inputSchema' => [] === $inputSchema ? [
                         'type' => 'object',
                         '$schema' => 'http://json-schema.org/draft-07/schema#',
-                    ],
+                    ] : $inputSchema,
                 ];
-            }, $this->toolbox->getMap()),
+            }, $this->toolbox->getMetadata()),
         ]);
     }