diff --git a/CHANGELOG.md b/CHANGELOG.md
index 29cea5b..1b6b76a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,13 @@
 All notable changes to this project will be documented in this file. This project adheres to
 [Semantic Versioning](http://semver.org/) and [this changelog format](http://keepachangelog.com/).
 
+## Unreleased (4.x)
+
+### Added
+
+- The `once` method has been added to the server repository interface. This previously existed on the concrete class,
+  but has now been added to the interface.
+
 ## Unreleased
 
 ## [3.3.0] - 2023-11-08
diff --git a/src/Contracts/Server/Repository.php b/src/Contracts/Server/Repository.php
index 10298dc..b5bbeae 100644
--- a/src/Contracts/Server/Repository.php
+++ b/src/Contracts/Server/Repository.php
@@ -21,12 +21,24 @@
 
 interface Repository
 {
-
     /**
      * Retrieve the named server.
      *
+     * This method MAY use thread-caching to optimise performance
+     * where multiple servers may be used.
+     *
      * @param string $name
      * @return Server
      */
     public function server(string $name): Server;
+
+    /**
+     * Retrieve the named server, to use once.
+     *
+     * This method MUST NOT use thread-caching.
+     *
+     * @param string $name
+     * @return Server
+     */
+    public function once(string $name): Server;
 }
diff --git a/src/Core/Server/ServerRepository.php b/src/Core/Server/ServerRepository.php
index 9099779..ce10b64 100644
--- a/src/Core/Server/ServerRepository.php
+++ b/src/Core/Server/ServerRepository.php
@@ -62,11 +62,7 @@ public function server(string $name): ServerContract
     }
 
     /**
-     * Use a server once, without thread-caching it.
-     *
-     * @param string $name
-     * @return ServerContract
-     * TODO add to interface
+     * @inheritDoc
      */
     public function once(string $name): ServerContract
     {