Ability to add the tool definitions to the system prompt

Author: OskarStark

src/Chain/InputProcessor/SystemPromptInputProcessor.php

@@ -6,6 +6,8 @@
 
 use PhpLlm\LlmChain\Chain\Input;
 use PhpLlm\LlmChain\Chain\InputProcessor;
+use PhpLlm\LlmChain\Chain\ToolBox\Metadata;
+use PhpLlm\LlmChain\Chain\ToolBox\ToolBoxInterface;
 use PhpLlm\LlmChain\Model\Message\Message;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
@@ -14,8 +16,13 @@
 {
     public function __construct(
         private string $systemPrompt,
+        private ?ToolBoxInterface $toolBox = null,
+        private bool $includeToolDefinitions = false,
         private LoggerInterface $logger = new NullLogger(),
     ) {
+        if ($includeToolDefinitions && null === $toolBox) {
+            throw new \InvalidArgumentException('Tool definitions cannot be included without a ToolBox.');
+        }
     }
 
     public function processInput(Input $input): void
@@ -28,6 +35,26 @@ public function processInput(Input $input): void
             return;
         }
 
-        $input->messages = $messages->prepend(Message::forSystem($this->systemPrompt));
+        $message = $this->systemPrompt;
+
+        if ($this->includeToolDefinitions) {
+            $tools = implode(PHP_EOL.PHP_EOL, array_map(
+                fn (Metadata $tool) => <<<TOOL
+## {$tool->name}
+{$tool->description}
+TOOL,
+                $this->toolBox->getMap()
+            ));
+
+            $message = <<<PROMPT
+{$this->systemPrompt}
+
+# Available tools
+
+{$tools}
+PROMPT;
+        }
+
+        $input->messages = $messages->prepend(Message::forSystem($message));
     }
 }

tests/Chain/InputProcessor/SystemPromptInputProcessorTest.php

@@ -7,11 +7,16 @@
 use PhpLlm\LlmChain\Bridge\OpenAI\GPT;
 use PhpLlm\LlmChain\Chain\Input;
 use PhpLlm\LlmChain\Chain\InputProcessor\SystemPromptInputProcessor;
+use PhpLlm\LlmChain\Chain\ToolBox\Metadata;
+use PhpLlm\LlmChain\Chain\ToolBox\ToolBoxInterface;
 use PhpLlm\LlmChain\Model\Message\Content\Text;
 use PhpLlm\LlmChain\Model\Message\Message;
 use PhpLlm\LlmChain\Model\Message\MessageBag;
 use PhpLlm\LlmChain\Model\Message\SystemMessage;
 use PhpLlm\LlmChain\Model\Message\UserMessage;
+use PhpLlm\LlmChain\Model\Response\ToolCall;
+use PhpLlm\LlmChain\Tests\Fixture\Tool\ToolNoParams;
+use PhpLlm\LlmChain\Tests\Fixture\Tool\ToolRequiredParams;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\Attributes\Small;
 use PHPUnit\Framework\Attributes\Test;
@@ -62,4 +67,94 @@ public function processInputDoesNotAddSystemMessageWhenOneExists(): void
         self::assertInstanceOf(UserMessage::class, $messages[1]);
         self::assertSame('This is already a system prompt', $messages[0]->content);
     }
+
+    #[Test]
+    public function needsToolboxToBeAbleToIncludeToolDefinitions(): void
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Tool definitions cannot be included without a ToolBox.');
+
+        new SystemPromptInputProcessor(
+            'This is a system prompt',
+            toolBox: null,
+            includeToolDefinitions: true,
+        );
+    }
+
+    #[Test]
+    public function includeToolDefinitions(): void
+    {
+        $processor = new SystemPromptInputProcessor(
+            'This is a system prompt',
+            new class implements ToolBoxInterface {
+                public function getMap(): array
+                {
+                    return [
+                        new Metadata(ToolNoParams::class, 'tool_no_params', 'A tool without parameters', '__invoke', null),
+                        new Metadata(
+                            ToolRequiredParams::class,
+                            'tool_required_params',
+                            <<<DESCRIPTION
+A tool with required parameters
+or not
+DESCRIPTION,
+                            'bar',
+                            null
+                        ),
+                    ];
+                }
+
+                public function execute(ToolCall $toolCall): mixed
+                {
+                    return null;
+                }
+            },
+            includeToolDefinitions: true,
+        );
+
+        $input = new Input(new GPT(), new MessageBag(Message::ofUser('This is a user message')), []);
+        $processor->processInput($input);
+
+        $messages = $input->messages->getMessages();
+        self::assertCount(2, $messages);
+        self::assertInstanceOf(SystemMessage::class, $messages[0]);
+        self::assertInstanceOf(UserMessage::class, $messages[1]);
+        self::assertSame(<<<PROMPT
+This is a system prompt
+
+# Available tools
+
+## tool_no_params
+A tool without parameters
+
+## tool_required_params
+A tool with required parameters
+or not
+PROMPT, $messages[0]->content);
+    }
+
+    private function createFaultyToolBox(\Closure $exceptionFactory): ToolBoxInterface
+    {
+        return new class($exceptionFactory) implements ToolBoxInterface {
+            public function __construct(private readonly \Closure $exceptionFactory)
+            {
+            }
+
+            /**
+             * @return Metadata[]
+             */
+            public function getMap(): array
+            {
+                return [
+                    new Metadata(ToolNoParams::class, 'tool_no_params', 'A tool without parameters', '__invoke', null),
+                    new Metadata(ToolRequiredParams::class, 'tool_required_params', 'A tool with required parameters', 'bar', null),
+                ];
+            }
+
+            public function execute(ToolCall $toolCall): mixed
+            {
+                throw ($this->exceptionFactory)($toolCall);
+            }
+        };
+    }
 }