diff --git a/README.md b/README.md
index 64dc025..a69c181 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,8 @@ Please refer to the [release page](https://github.com/actions/checkout/releases/
     clean: ''
 
     # Partially clone against a given filter. Overrides sparse-checkout if set.
+    # Note that when a filter is provided, fetch-depth is still respected; you
+    # may want to specify `fetch-depth: 0` to ensure the full history is fetched.
     # Default: null
     filter: ''
 
diff --git a/action.yml b/action.yml
index 6842eb8..9bbe421 100644
--- a/action.yml
+++ b/action.yml
@@ -59,8 +59,9 @@ inputs:
     default: true
   filter:
     description: >
-      Partially clone against a given filter.
-      Overrides sparse-checkout if set.
+      Partially clone against a given filter. Overrides sparse-checkout if set.
+      Note that when a filter is provided, fetch-depth is still respected; you
+      may want to specify `fetch-depth: 0` to ensure the full history is fetched.
     default: null
   sparse-checkout:
     description: >