File Core/Schema/ProtocolVersion.php

1:	<?php
2:
3:	declare(strict_types=1);
4:
5:	/**
6:	* This file is part of the Nexus MCP SDK package.
7:	*
8:	* (c) 2026 John Paul E. Balandan, CPA <paulbalandan@gmail.com>
9:	*
10:	* For the full copyright and license information, please view
11:	* the LICENSE file that was distributed with this source code.
12:	*/
13:
14:	namespace Nexus\Mcp\Core\Schema;
15:
16:	use Nexus\Assert\Assert;
17:
18:	/**
19:	* A revision of the Model Context Protocol identified by its release date.
20:	*
21:	* @see https://modelcontextprotocol.io/specification/draft/basic/lifecycle#protocol-version-negotiation
22:	*/
23:	final readonly class ProtocolVersion
24:	{
25:	public const string LATEST_VERSION = '2026-07-28';
26:
27:	/**
28:	* Superseded spec revisions, newest first.
29:	*/
30:	public const array PREVIOUS_VERSIONS = [
31:	'2025-11-25',
32:	'2025-06-18',
33:	'2025-03-26',
34:	'2024-11-05',
35:	];
36:
37:	/**
38:	* The protocol revisions this server implements, newest first.
39:	*/
40:	public const array SUPPORTED_VERSIONS = [self::LATEST_VERSION];
41:
42:	/**
43:	* @var non-empty-string
44:	*/
45:	public string $version;
46:
47:	public function __construct(string $version)
48:	{
49:	Assert::that($version)
50:	->isNonEmptyString('"protocolVersion" must be a non-empty string.')
51:	->matchesRegularExpression('/\A\d{4}-\d{2}-\d{2}\z/', '"protocolVersion" must be in the format "YYYY-MM-DD".')
52:	;
53:
54:	$this->version = $version;
55:	}
56:	}
57: