diff --git a/cli/src/commands/util/gc.rs b/cli/src/commands/util/gc.rs
index eef16ce00ab..9cf5d8aaea0 100644
--- a/cli/src/commands/util/gc.rs
+++ b/cli/src/commands/util/gc.rs
@@ -27,6 +27,9 @@ use crate::ui::Ui;
 ///
 /// To garbage-collect old operations and the commits/objects referenced by
 /// then, run `jj op abandon ..<some old operation>` before `jj util gc`.
+///
+/// Note that previous versions of a change that are reachable via the evolution
+/// log are not currently garbage-collected.
 #[derive(clap::Args, Clone, Debug)]
 pub struct UtilGcArgs {
     /// Time threshold
diff --git a/cli/tests/cli-reference@.md.snap b/cli/tests/cli-reference@.md.snap
index d89f4337287..ba7c5e74118 100644
--- a/cli/tests/cli-reference@.md.snap
+++ b/cli/tests/cli-reference@.md.snap
@@ -2268,6 +2268,8 @@ Run backend-dependent garbage collection.
 
 To garbage-collect old operations and the commits/objects referenced by then, run `jj op abandon ..<some old operation>` before `jj util gc`.
 
+At present, jj's garbage collection is not comprehensive. If a commit is preserved by the garbage collection, objects reachable from its evolution log cannot be garbage collected.
+
 **Usage:** `jj util gc [OPTIONS]`
 
 ###### **Options:**