[Adebayo120]

Summary

• Fix schema validation for nested empty JSON objects by preserving object context from the surrounding schema when json_decode(..., true) turns {} into an empty PHP array.
• Add a regression test covering a nested object like {"parameters": {}} that previously failed with Expected object, but received array.

Reproduction

use Mcp\Capability\Discovery\SchemaValidator;

$data = json_decode('{"parameters":{}}', true, 512, JSON_THROW_ON_ERROR);
$schema = [
    'type' => 'object',
    'properties' => [
        'parameters' => ['type' => 'object'],
    ],
];

$validator = new SchemaValidator();
var_export($validator->validateAgainstJsonSchema($data, $schema));

Before the fix this returned an error complaining /parameters was an array rather than an object.

Validation

• php vendor/bin/phpunit tests/Unit/Capability/Discovery/SchemaValidatorTest.php
• php vendor/bin/phpstan analyse --no-progress --configuration=phpstan.dist.neon src/Capability/Discovery/SchemaValidator.php tests/Unit/Capability/Discovery/SchemaValidatorTest.php
• php vendor/bin/php-cs-fixer fix --config=.php-cs-fixer.dist.php --dry-run --diff src/Capability/Discovery/SchemaValidator.php tests/Unit/Capability/Discovery/SchemaValidatorTest.php