diff --git a/crates/engine/src/analysis/frames_key.rs b/crates/engine/src/analysis/frames_key.rs
index 44eb93d57..248b3b4f5 100644
--- a/crates/engine/src/analysis/frames_key.rs
+++ b/crates/engine/src/analysis/frames_key.rs
@@ -9,7 +9,7 @@
 //! doesn't change keys. Of the layer and of a precomp, only the fields named in `layer_frames` are
 //! read (a precomp's contents are #3535). The
 //! text leaves out observations (whether footage is available) and data that never changes pixels
-//! (names, labels, UI hints, markers), so they never drop saved analyses (#3534, #3536).
+//! (colour labels, UI hints, markers), so they never drop saved analyses (#3534, #3536).
 //!
 //! Keys saved by 0.22–0.24 hashed derived `Debug` text instead. [`legacy`] still recognises
 //! them, and a matching saved key is kept rather than rewritten: frozen Roto Brush mattes and
@@ -348,13 +348,15 @@ impl Text {
     }
 
     fn group(&mut self, g: &PropGroup, depth: usize) {
-        // The uid, name and colour label identify and label the group; they never change pixels.
-        let PropGroup { uid: _, match_id, name: _, kind, enabled, label: _, children } = g;
+        // Expressions find effects and groups by name (`effect("Blur")`, `propertyGroup(1).name`).
+        // The uid and colour label never change pixels.
+        let PropGroup { uid: _, match_id, name, kind, enabled, label: _, children } = g;
         if depth >= MAX_DEPTH {
             self.word("tooDeep");
             return;
         }
         self.str("group", match_id);
+        self.str("name", name);
         self.group_kind(kind);
         self.field("enabled", enabled);
         for c in children {
@@ -415,24 +417,16 @@ impl Text {
     }
 
     fn property(&mut self, pr: &Property) {
-        // The uid, name and UI hints identify and show the property; the 2D/3D-only and
-        // hold-only flags say where and how it can be edited, not what it evaluates to.
-        let Property {
-            uid: _,
-            match_id,
-            name: _,
-            value,
-            keys,
-            expr,
-            ui: _,
-            spatial,
-            hold_only: _,
-            three_d_only: _,
-            two_d_only: _,
-            shown_dims: _,
-            static_only: _,
-        } = pr;
+        // Expressions read the name (`thisProperty.name`) and seed `random`/`wiggle` with the
+        // uid: the uid is written for a property with an expression. UI hints and the 2D/3D-only
+        // and hold-only flags say where and how it can be edited, not what it evaluates to.
+        let Property { uid, match_id, name, value, keys, expr, ui: _, spatial, hold_only: _, three_d_only: _, two_d_only: _, shown_dims: _, static_only: _ } =
+            pr;
         self.str("prop", match_id);
+        self.str("name", name);
+        if expr.is_some() {
+            self.field("uid", uid);
+        }
         self.value(value);
         self.field("spatial", spatial);
         for k in keys {
diff --git a/crates/engine/src/tests/analysis_signature.rs b/crates/engine/src/tests/analysis_signature.rs
index 96323e6be..b73c79edd 100644
--- a/crates/engine/src/tests/analysis_signature.rs
+++ b/crates/engine/src/tests/analysis_signature.rs
@@ -100,7 +100,7 @@ fn analyses_saved_by_0_24_survive_edits_that_keep_their_frames() {
 fn signature_text_is_pinned() {
     let s = open(ANALYSED_0_24);
     let layer = s.project.comp(COMP).unwrap().layer(CLIP).unwrap();
-    let key = r#"frames/1;footage=1;footage;path="/tmp/effectcraft-3456-shake.mp4";kind=video;w=160;h=120;par=1.0;rate=12/1;nativeRate=none;duration=254016000000;video=true;audio=false;alpha=ignore;matte=[0.0, 0.0, 0.0];loop=1;codec="H.264 (High)";frames=0;profile{rec709;};layer=none;fields=off;invertAlpha=false;linearLight=false;preserveRgb=false;cineon;log=false;points=[0.0, 1023.0, 95.0, 685.0, 1.7, 20.0];units=10bit;data=none;page=0;alphabetical=false;startTimecode=none;fileTimecode=none;placedPage=false;in=0;out=254016000000;start=0;stretch=100.0;timeRemap{prop="timeRemap";scalar=0.0;spatial=false;key=0;scalar=0.2;interp=linear/linear;continuous=false;autoBezier=false;spatialIn=[0.0, 0.0, 0.0];spatialOut=[0.0, 0.0, 0.0];spatialAuto=true;spatialContinuous=false;roving=false;muted=false;key=254016000000;scalar=1.0;interp=linear/linear;continuous=false;autoBezier=false;spatialIn=[0.0, 0.0, 0.0];spatialOut=[0.0, 0.0, 0.0];spatialAuto=true;spatialContinuous=false;roving=false;muted=false;expr=none;};compRate{rate=12/1;};"#;
+    let key = r#"frames/1;footage=1;footage;path="/tmp/effectcraft-3456-shake.mp4";kind=video;w=160;h=120;par=1.0;rate=12/1;nativeRate=none;duration=254016000000;video=true;audio=false;alpha=ignore;matte=[0.0, 0.0, 0.0];loop=1;codec="H.264 (High)";frames=0;profile{rec709;};layer=none;fields=off;invertAlpha=false;linearLight=false;preserveRgb=false;cineon;log=false;points=[0.0, 1023.0, 95.0, 685.0, 1.7, 20.0];units=10bit;data=none;page=0;alphabetical=false;startTimecode=none;fileTimecode=none;placedPage=false;in=0;out=254016000000;start=0;stretch=100.0;timeRemap{prop="timeRemap";name="Time Remap";scalar=0.0;spatial=false;key=0;scalar=0.2;interp=linear/linear;continuous=false;autoBezier=false;spatialIn=[0.0, 0.0, 0.0];spatialOut=[0.0, 0.0, 0.0];spatialAuto=true;spatialContinuous=false;roving=false;muted=false;key=254016000000;scalar=1.0;interp=linear/linear;continuous=false;autoBezier=false;spatialIn=[0.0, 0.0, 0.0];spatialOut=[0.0, 0.0, 0.0];spatialAuto=true;spatialContinuous=false;roving=false;muted=false;expr=none;};compRate{rate=12/1;};"#;
     assert_eq!(crate::analysis::frames_key::signature_text(&s.project, COMP, layer), key);
 }
 
@@ -151,11 +151,10 @@ fn todays_keys_survive_edits_that_keep_their_frames() {
         add_to_render_queue(&mut s);
         assert_eq!(saved(&s), before);
     }
-    // Names and labels only show things.
-    s.execute_checked("layer.rename", json!({"layer": CLIP.0, "name": "Renamed"})).unwrap();
-    s.edit("rename", None, |p, _| {
+    // Colour labels and footage markers only show things.
+    s.edit("label", None, |p, _| {
         let l = p.comp_mut(COMP).unwrap().layer_mut(CLIP).unwrap();
-        l.props.find_group_mut(82).unwrap().name = "Soft".into();
+        l.props.find_group_mut(82).unwrap().label = Some(effectcraft_color::Label::Yellow);
         if let Some(effectcraft_project::ItemKind::Footage(f)) = p.item_mut(ItemId(1)).map(|i| &mut i.kind) {
             f.markers.push(effectcraft_project::Marker::default());
         }
@@ -163,6 +162,16 @@ fn todays_keys_survive_edits_that_keep_their_frames() {
     })
     .unwrap();
     assert_eq!(saved(&s), before);
+    // Expressions find effects by name: renaming the effect above the Roto Brush is a change for it.
+    s.edit("rename", None, |p, _| {
+        p.comp_mut(COMP).unwrap().layer_mut(CLIP).unwrap().props.find_group_mut(82).unwrap().name = "Soft".into();
+        Ok(())
+    })
+    .unwrap();
+    assert_eq!(saved(&s)[..2], before[..2]);
+    assert_eq!(saved(&s)[2].0, "");
+    s.execute_checked("edit.undo", json!({})).unwrap();
+    assert_eq!(saved(&s), before);
 
     // A real change still clears them.
     s.execute_checked("file.interpretFootage", json!({"items": [1], "invertAlpha": true})).unwrap();
@@ -234,3 +243,22 @@ fn keys_saved_by_0_24_while_offline_still_match() {
         assert_eq!(roto(&s), ("saved frozen".into(), ROTO_INPUT_0_24_OFFLINE.into()));
     }
 }
+
+/// Expressions seed `random` and `wiggle` with the property's uid: a Time Remap with an expression
+/// keys its uid (a duplicated layer gets new uids), one without doesn't.
+#[test]
+fn an_expression_keys_its_property_uid() {
+    let s = open(ANALYSED_0_24);
+    let layer = s.project.comp(COMP).unwrap().layer(CLIP).unwrap().clone();
+    let text = |l: &effectcraft_project::Layer| crate::analysis::frames_key::signature_text(&s.project, COMP, l);
+    let renumbered = |l: &effectcraft_project::Layer| {
+        let mut l = l.clone();
+        l.props.get_mut("timeRemap").unwrap().uid += 1000;
+        l
+    };
+    assert_eq!(text(&renumbered(&layer)), text(&layer));
+    let mut with_expr = layer.clone();
+    with_expr.props.get_mut("timeRemap").unwrap().expr =
+        Some(effectcraft_project::Expression { text: "seedRandom(0, true); random(0, 1)".into(), enabled: true });
+    assert_ne!(text(&renumbered(&with_expr)), text(&with_expr));
+}