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 Prism\Prism\Prism;
use Prism\Prism\Enums\Provider;
use Prism\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.";
    });

$response = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withMaxSteps(2)
    ->withPrompt('What is the weather like in Paris?')
    ->withTools([$weatherTool])
    ->asText();

Max Steps

Prism defaults to allowing a single step. To use Tools, you'll need to increase this using withMaxSteps:

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

Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    // Increase max steps to at least 2
    ->withMaxSteps(2)
    ->withPrompt('What is the weather like in Paris?')
    ->withTools([$weatherTool])
    ->asText();

You should use a higher number of max steps if you expect your initial prompt to make multiple tool calls.

Creating Basic Tools

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

use Prism\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}";
    });

Tools can take a variety of parameters, but must always return a string.

Error Handling

By default, tools handle invalid parameters gracefully by returning error messages instead of throwing exceptions. This helps AI assistants understand and potentially correct their mistakes.

$tool = Tool::as('calculate')
    ->for('Add two numbers')
    ->withNumberParameter('a', 'First number')
    ->withNumberParameter('b', 'Second number')
    ->using(fn (int $a, int $b): string => (string) ($a + $b));

// If AI provides invalid parameters, it receives:
// "Parameter validation error: Type mismatch. Expected: [a (NumberSchema, required), b (NumberSchema, required)]. Received: {"a":"five","b":10}"

Opting Out

If you prefer exceptions for invalid parameters:

// Per-tool
$tool->withoutErrorHandling();

// Per-request
Prism::text()->withoutToolErrorHandling();

Best Practice: Use default error handling for conversational AI. Disable it only when you need strict validation that stops execution.

Parameter Definition

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

String Parameters

Perfect for text inputs:

use Prism\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 Prism\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 Prism\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 Prism\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 Prism\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 Prism\Prism\Facades\Tool;
use Prism\Prism\Schema\StringSchema;
use Prism\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 Prism\Prism\Facades\Tool;
use Prism\Prism\Schema\ObjectSchema;
use Prism\Prism\Schema\StringSchema;
use Prism\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 Prism\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 withToolChoice method:

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

$prism = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withMaxSteps(2)
    ->withPrompt('How is the weather in Paris?')
    ->withTools([$weatherTool])
    // Let the AI decide whether to use tools
    ->withToolChoice(ToolChoice::Auto)
    // Force the AI to use a tool
    ->withToolChoice(ToolChoice::Any)
    // Force the AI to use a specific tool
    ->withToolChoice('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 Prism\Prism\Prism;
use Prism\Prism\Enums\Provider;

$response = Prism::text()
    ->using(Provider::Anthropic, 'claude-3-5-sonnet-latest')
    ->withMaxSteps(2)
    ->withPrompt('What is the weather like in Paris?')
    ->withTools([$weatherTool])
    ->asText();

// 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";
        }
    }
}

Provider Tools

In addition to custom tools that you define, Prism supports provider tools - built-in capabilities offered directly by AI providers. These are specialized tools that leverage the provider's own infrastructure and services.

Understanding Provider Tools vs Custom Tools

Custom Tools (covered above) are functions you define and implement yourself:

• You control the logic and implementation
• Called by the AI, executed by your code
• Can access your databases, APIs, and services

Provider Tools are built-in capabilities offered by the AI provider:

• Implemented and executed by the provider
• Access the provider's own services and infrastructure
• Enable capabilities like code execution, web search, and more

Using Provider Tools

Provider tools are added to your requests using the withProviderTools() method with ProviderTool objects:

use Prism\Prism\Prism;
use Prism\Prism\ValueObjects\ProviderTool;

$response = Prism::text()
    ->using('anthropic', 'claude-3-5-sonnet-latest')
    ->withPrompt('Calculate the fibonacci sequence up to 100')
    ->withProviderTools([
        new ProviderTool(type: 'code_execution_20250522', name: 'code_execution')
    ])
    ->asText();

Available Provider Tools

Each provider offers different built-in capabilities. Check the provider-specific documentation for detailed information about available tools, configuration options, and usage examples.

ProviderTool Object

The ProviderTool class accepts three parameters:

new ProviderTool(
    type: 'code_execution_20250522',  // Required: The provider tool identifier
    name: 'code_execution',           // Optional: Custom name for the tool
    options: []                       // Optional: Provider-specific options
)

• type: The provider-specific tool identifier (required)
• name: Optional custom name for the tool
• options: Additional provider-specific configuration options

Combining Provider Tools and Custom Tools

You can use both provider tools and custom tools in the same request:

use Prism\Prism\Prism;
use Prism\Prism\ValueObjects\ProviderTool;
use Prism\Prism\Facades\Tool;

$customTool = Tool::as('database_lookup')
    ->for('Look up user information')
    ->withStringParameter('user_id', 'The user ID to look up')
    ->using(function (string $userId): string {
        // Your database lookup logic
        return "User data for ID: {$userId}";
    });

$response = Prism::text()
    ->using('anthropic', 'claude-3-5-sonnet-latest')
    ->withMaxSteps(5)
    ->withPrompt('Look up user 123 and calculate their usage statistics')
    ->withTools([$customTool])
    ->withProviderTools([
        new ProviderTool(type: 'code_execution_20250522', name: 'code_execution')
    ])
    ->asText();