Tools & Function Calling

Need your AI assistant to check the weather, search a database, or call your API? Tools are here to help! They let you extend your AI's capabilities by giving it access to specific functions it can call.

Tool Concept Overview

Think of tools as special functions that your AI assistant can use when it needs to perform specific tasks. Just like how Laravel's facades provide a clean interface to complex functionality, Prism tools give your AI a clean way to interact with external services and data sources.

use EchoLabs\Prism\Facades\Tool;

$weatherTool = Tool::as('weather')
    ->for('Get current weather conditions')
    ->withStringParameter('city', 'The city to get weather for')
    ->using(function (string $city): string {
        // Your weather API logic here
        return "The weather in {$city} is sunny and 72°F.";
    });

Creating Basic Tools

Creating tools in Prism is straightforward and fluent. Here's how you can create a simple tool:

use EchoLabs\Prism\Facades\Tool;

$searchTool = Tool::as('search')
    ->for('Search for current information')
    ->withStringParameter('query', 'The search query')
    ->using(function (string $query): string {
        // Your search implementation
        return "Search results for: {$query}";
    });

Parameter Definition

Prism offers multiple ways to define tool parameters, from simple primitives to complex objects.

String Parameters

Perfect for text inputs:

use EchoLabs\Prism\Facades\Tool;

$tool = Tool::as('search')
    ->for('Search for information')
    ->withStringParameter('query', 'The search query')
    ->using(function (string $query): string {
        return "Search results for: {$query}";
    });

Number Parameters

For integer or floating-point values:

use EchoLabs\Prism\Facades\Tool;

$tool = Tool::as('calculate')
    ->for('Perform calculations')
    ->withNumberParameter('value', 'The number to process')
    ->using(function (float $value): string {
        return "Calculated result: {$value * 2}";
    });

Boolean Parameters

For true/false flags:

use EchoLabs\Prism\Facades\Tool;

$tool = Tool::as('feature_toggle')
    ->for('Toggle a feature')
    ->withBooleanParameter('enabled', 'Whether to enable the feature')
    ->using(function (bool $enabled): string {
        return "Feature is now " . ($enabled ? 'enabled' : 'disabled');
    });

Array Parameters

For handling lists of items:

use EchoLabs\Prism\Facades\Tool;

$tool = Tool::as('process_tags')
    ->for('Process a list of tags')
    ->withArrayParameter(
        'tags',
        'List of tags to process',
        new StringSchema('tag', 'A single tag')
    )
    ->using(function (array $tags): string {
        return "Processing tags: " . implode(', ', $tags);
    });

Enum Parameters

When you need to restrict values to a specific set:

use EchoLabs\Prism\Facades\Tool;

$tool = Tool::as('set_status')
    ->for('Set the status')
    ->withEnumParameter(
        'status',
        'The new status',
        ['draft', 'published', 'archived']
    )
    ->using(function (string $status): string {
        return "Status set to: {$status}";
    });

Object Parameters

For complex objects without needing to create separate schema instances:

use EchoLabs\Prism\Facades\Tool;
use EchoLabs\Prism\Schema\StringSchema;
use EchoLabs\Prism\Schema\NumberSchema;

$tool = Tool::as('update_user')
    ->for('Update a user profile')
    ->withObjectParameter(
        'user',
        'The user profile data',
        [
            new StringSchema('name', 'User\'s full name'),
            new NumberSchema('age', 'User\'s age'),
            new StringSchema('email', 'User\'s email address')
        ],
        requiredFields: ['name', 'email']
    )
    ->using(function (array $user): string {
        return "Updated user profile for: {$user['name']}";
    });

Schema-based Parameters

For complex, nested data structures, you can use Prism's schema system:

use EchoLabs\Prism\Facades\Tool;
use EchoLabs\Prism\Schema\ObjectSchema;
use EchoLabs\Prism\Schema\StringSchema;
use EchoLabs\Prism\Schema\NumberSchema;

$tool = Tool::as('create_user')
    ->for('Create a new user profile')
    ->withParameter(new ObjectSchema(
        name: 'user',
        description: 'The user profile data',
        properties: [
            new StringSchema('name', 'User\'s full name'),
            new NumberSchema('age', 'User\'s age'),
            new StringSchema('email', 'User\'s email address')
        ],
        requiredFields: ['name', 'email']
    ))
    ->using(function (array $user): string {
        return "Created user profile for: {$user['name']}";
    });

TIP

For more complex parameter definitions, Prism provides a powerful schema system. See our complete schemas guide to learn how to define complex nested objects, arrays, enums, and more.

Complex Tool Implementation

For more sophisticated tools, you can create dedicated classes:

namespace App\Tools;

use EchoLabs\Prism\Tool;
use Illuminate\Support\Facades\Http;

class SearchTool extends Tool
{
    public function __construct()
    {
        $this
            ->as('search')
            ->for('useful when you need to search for current events')
            ->withStringParameter('query', 'Detailed search query. Best to search one topic at a time.')
            ->using($this);
    }

    public function __invoke(string $query): string
    {
        $response = Http::get('https://serpapi.com/search', [
            'engine' => 'google',
            'q' => $query,
            'google_domain' => 'google.com',
            'gl' => 'us',
            'hl' => 'en',
            'api_key' => config('services.serpapi.api_key'),
        ]);

        $results = collect($response->json('organic_results'));

        $results->map(function ($result) {
            return [
                'title' => $result['title'],
                'link' => $result['link'],
                'snippet' => $result['snippet'],
            ];
        })->take(4);

        return view('prompts.search-tool-results', [
            'results' => $results,
        ])->render();
    }
}

Tool Choice Options

You can control how the AI uses tools with the toolChoice method:

use EchoLabs\Prism\Prism;
use EchoLabs\Prism\Enums\Provider;
use EchoLabs\Prism\Enums\ToolChoice;

$prism = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withPrompt('How is the weather in Paris?')
    ->withTools([$weatherTool])
    // Let the AI decide whether to use tools
    ->toolChoice(ToolChoice::Auto)
    // Force the AI to use a tool
    ->toolChoice(ToolChoice::Any)
    // Force the AI to use a specific tool
    ->toolChoice('weather');

WARNING

Tool choice support varies by provider. Check your provider's documentation for specific capabilities.

Response Handling with Tools

When your AI uses tools, you can inspect the results and see how it arrived at its answer:

use EchoLabs\Prism\Prism;
use EchoLabs\Prism\Enums\Provider;

$response = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withPrompt('What is the weather like in Paris?')
    ->withTools([$weatherTool])
    ->generate();

// Get the final answer
echo $response->text;

// ->text is empty for tool calls

// Inspect tool usage

if ($response->toolResults) {
    foreach ($response->toolResults as $toolResult) {
        echo "Tool: " . $toolResult->toolName . "\n";
        echo "Result: " . $toolResult->result . "\n";
    }
}


foreach ($response->steps as $step) {
    if ($step->toolCalls) {
        foreach ($step->toolCalls as $toolCall) {
            echo "Tool: " . $toolCall->name . "\n";
            echo "Arguments: " . json_encode($toolCall->arguments()) . "\n";
        }
    }
}