diff --git a/src/ServerBuilder.php b/src/ServerBuilder.php
index dacfda3..c8931a0 100644
--- a/src/ServerBuilder.php
+++ b/src/ServerBuilder.php
@@ -98,9 +98,13 @@ public function __construct() {}
     /**
      * Sets the server's identity. Required.
      */
-    public function withServerInfo(string $name, string $version): self
+    public function withServerInfo(string $name, string $version, ?string $instructions = null): self
     {
-        $this->serverInfo = Implementation::make(name: trim($name), version: trim($version));
+        $this->serverInfo = Implementation::make(
+            name: trim($name), 
+            version: trim($version), 
+            instructions: $instructions ? trim($instructions) : null
+        );
 
         return $this;
     }