From 6d3ea0194f6fc666d7bb323d1226d7657910fdf7 Mon Sep 17 00:00:00 2001
From: Sergey Shevchenko <gurucomkz@users.noreply.github.com>
Date: Wed, 15 Apr 2026 14:33:26 +1200
Subject: [PATCH] Add optional instructions to Implementation class

---
 src/Implementation.php | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/Implementation.php b/src/Implementation.php
index 591bf23..ff33384 100644
--- a/src/Implementation.php
+++ b/src/Implementation.php
@@ -7,27 +7,32 @@
 use JsonSerializable;
 
 /**
- * Describes the name and version of an MCP implementation.
+ * Describes the name, version and optional usage instructions of an MCP implementation.
  */
 class Implementation implements JsonSerializable
 {
     public function __construct(
         public readonly string $name,
-        public readonly string $version
+        public readonly string $version,
+        public readonly ?string $instructions = null,
     ) {
     }
 
-    public static function make(string $name, string $version): static
+    public static function make(string $name, string $version, ?string $instructions = null): static
     {
-        return new static($name, $version);
+        return new static($name, $version, $instructions);
     }
 
     public function toArray(): array
     {
-        return [
+        $result = [
             'name' => $this->name,
             'version' => $this->version,
         ];
+        if ($this->instructions !== null) {
+            $result['instructions'] = $this->instructions;
+        }
+        return $result;
     }
 
     public static function fromArray(array $data): static
@@ -38,7 +43,7 @@ public static function fromArray(array $data): static
         if (empty($data['version']) || !is_string($data['version'])) {
             throw new \InvalidArgumentException("Invalid or missing 'version' in Implementation data.");
         }
-        return new static($data['name'], $data['version']);
+        return new static($data['name'], $data['version'], $data['instructions'] ?? null);
     }
 
     public function jsonSerialize(): array