diff --git a/crates/engine/src/cmd/structure.rs b/crates/engine/src/cmd/structure.rs
index 5643c058f..f5dd3e0df 100644
--- a/crates/engine/src/cmd/structure.rs
+++ b/crates/engine/src/cmd/structure.rs
@@ -610,6 +610,10 @@ fn offset_path(s: &mut Session, p: &Value) -> Result<Value> {
     for i in req_targets("vector.offset", s, p)? {
         let doc = s.doc_mut()?;
         let n = doc.get(i)?.clone();
+        // A vector can't hold children: leave containers (frames, groups, instances) alone.
+        if !n.children.is_empty() {
+            continue;
+        }
         let Some((path, _)) = figcraft_render::node_outline(doc, &n) else { continue };
         let props = StrokeProps { weight: d.abs() * 2.0, join: StrokeJoin::Round, align: StrokeAlign::Center, ..Default::default() };
         let ring = figcraft_pathops::stroke_center(&path, d.abs() * 2.0, &props);
diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index 2937c201c..c692daa10 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -1732,6 +1732,8 @@ mod vector_behaviour_tests;
 #[cfg(test)]
 mod vector_multi_behaviour_tests;
 #[cfg(test)]
+mod vector_offset_tests;
+#[cfg(test)]
 mod version_preview_tests;
 #[cfg(test)]
 mod version_tests;
diff --git a/crates/engine/src/vector_offset_tests.rs b/crates/engine/src/vector_offset_tests.rs
new file mode 100644
index 000000000..e47158f29
--- /dev/null
+++ b/crates/engine/src/vector_offset_tests.rs
@@ -0,0 +1,49 @@
+//! `vector.offset` on layers with children: containers are left alone.
+
+use serde_json::{Value, json};
+
+use crate::Session;
+use crate::params::id_of;
+use figcraft_doc::{NodeId, NodeKind};
+
+fn id(v: &Value) -> NodeId {
+    id_of(&v["id"]).unwrap()
+}
+
+/// No node that holds children may be a non-container.
+fn assert_children_only_in_containers(s: &Session, ids: &[NodeId]) {
+    let doc = s.doc().unwrap();
+    for &i in ids {
+        let n = doc.node(i).unwrap();
+        assert!(n.kind.is_container() || n.kind.is_frame_like() || n.children.is_empty(), "a non-container layer now holds children");
+    }
+}
+
+#[test]
+fn offset_path_leaves_containers_with_children_alone() {
+    let mut s = Session::new();
+    let f = id(&s.execute("frame.create", &json!({"x": 0, "y": 0, "width": 100, "height": 100})).unwrap());
+    let inner = id(&s.execute("shape.rectangle", &json!({"x": 10, "y": 10, "width": 10, "height": 10, "parent": f})).unwrap());
+    let a = id(&s.execute("shape.rectangle", &json!({"x": 200, "y": 0, "width": 10, "height": 10})).unwrap());
+    let b = id(&s.execute("shape.rectangle", &json!({"x": 220, "y": 0, "width": 10, "height": 10})).unwrap());
+    let g = id(&s.execute("object.group", &json!({"ids": [a, b]})).unwrap());
+    for target in [f, g] {
+        s.execute("vector.offset", &json!({"ids": [target], "offset": 5})).unwrap();
+        assert_children_only_in_containers(&s, &[f, g, inner, a, b]);
+    }
+    let doc = s.doc().unwrap();
+    assert!(doc.node(f).unwrap().kind.is_container());
+    assert_eq!(doc.node(f).unwrap().children, vec![inner]);
+    assert!(doc.node(g).unwrap().kind.is_container());
+    assert_eq!(doc.node(g).unwrap().children.len(), 2);
+}
+
+#[test]
+fn offset_path_still_converts_a_plain_rectangle() {
+    let mut s = Session::new();
+    let r = id(&s.execute("shape.rectangle", &json!({"x": 0, "y": 0, "width": 10, "height": 10})).unwrap());
+    s.execute("vector.offset", &json!({"ids": [r], "offset": 5})).unwrap();
+    let n = s.doc().unwrap().node(r).unwrap().clone();
+    assert!(matches!(n.kind, NodeKind::Vector { .. }));
+    assert!(n.width > 10.0);
+}