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Getting Started

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Your First Prompt

Extend Prompt and implement body(). That’s it. 
use Cognesy\Xprompt\Prompt;

class Greeting extends Prompt
{
    public function body(mixed ...$ctx): string
    {
        return "Hello, {$ctx['name']}!";
    }
}
// @doctest id="c0d1"
Render it: 
echo Greeting::with(name: 'Alice');
// "Hello, Alice!"
// @doctest id="4e1e"

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Creating Instances

There are two static constructors: 
// Bare instance — context passed at render time
$prompt = Greeting::make();
echo $prompt->render(name: 'Bob');

// Pre-bound context — stored and merged at render time
$prompt = Greeting::with(name: 'Charlie');
echo $prompt->render(); // "Hello, Charlie!"
// @doctest id="a871"

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Passing Context

Context is passed as named arguments. Pre-bound context from with() merges with context passed to render(), with render-time values taking precedence: 
class Welcome extends Prompt
{
    public function body(mixed ...$ctx): string
    {
        return "{$ctx['greeting']}, {$ctx['name']}!";
    }
}

$prompt = Welcome::with(greeting: 'Hi');
echo $prompt->render(name: 'Dana');            // "Hi, Dana!"
echo $prompt->render(name: 'Eve', greeting: 'Hey'); // "Hey, Eve!"
// @doctest id="9516"

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Stringable

Every prompt implements Stringable, so you can use it anywhere PHP accepts a string: 
$persona = Persona::with(role: 'analyst');

// String concatenation
$full = "System: " . $persona;

// String interpolation
echo "Using prompt: {$persona}";

// Pass to any API accepting string|Stringable
$inference->withSystem($persona)->create();
// @doctest id="b04a"

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Returning Null

A body() that returns null renders as an empty string. This is intentional — it enables conditional composition, which is covered in Composition. 
class MaybeDisclaimer extends Prompt
{
    public function body(mixed ...$ctx): string|array|null
    {
        return ($ctx['strict'] ?? false)
            ? 'Follow instructions exactly. Do not improvise.'
            : null;
    }
}
// @doctest id="8f4d"

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Next Steps

  • Composition — combine prompts into larger structures
  • Templates — use Twig files for complex prompt content