diff --git a/src/Analyser/ResultCache/ResultCacheValueExtension.php b/src/Analyser/ResultCache/ResultCacheValueExtension.php
index f15e7daaeea..02aa16ed4f1 100644
--- a/src/Analyser/ResultCache/ResultCacheValueExtension.php
+++ b/src/Analyser/ResultCache/ResultCacheValueExtension.php
@@ -40,6 +40,8 @@ interface ResultCacheValueExtension
 	/**
 	 * The current value for the key - compared with the one recorded by the last analysis.
 	 * A long value is better hashed.
+	 *
+	 * `getValue` is invoked before [`bootstrapFiles`](https://phpstan.org/config-reference#bootstrap) are included.
 	 */
 	public function getValue(string $key): string;