diff --git a/crates/engine/src/al_behaviour_tests.rs b/crates/engine/src/al_behaviour_tests.rs
index a7a4d1d7..d36b35b8 100644
--- a/crates/engine/src/al_behaviour_tests.rs
+++ b/crates/engine/src/al_behaviour_tests.rs
@@ -6,7 +6,7 @@ use serde_json::{Value, json};
 
 use crate::Session;
 use crate::params::id_of;
-use figcraft_doc::{CellAlign, MainAlign, NodeId, Sizing};
+use figcraft_doc::{CellAlign, CrossAlign, LayoutMode, MainAlign, NodeId, Sizing};
 
 fn id(v: Value) -> NodeId {
     id_of(&v["id"]).unwrap()
@@ -233,3 +233,46 @@ fn a_size_given_with_a_new_path_fixes_that_axis() {
     assert_eq!(sizing(&s, v).0, Sizing::Fixed);
     assert!((size(&s, v).0 - 30.0).abs() < 1e-6, "{:?}", size(&s, v));
 }
+
+/// What one call's auto layout keys give, whichever way they are spelled: the mode (a string, or
+/// an object that replaces the whole auto layout) applies first and the other keys tune it.
+#[test]
+fn auto_layout_keys_in_one_call_tune_the_mode_given_beside_them() {
+    for (key, mode) in ["layout", "layoutMode"].into_iter().flat_map(|k| [(k, json!("vertical")), (k, json!({"mode": "vertical"}))]) {
+        let mut props = json!({"gap": 8, "padding": 4, "crossAlign": "center"});
+        props[key] = mode;
+        let mut s = Session::new();
+        let created = id(s.execute("node.create", &json!({"type": "frame", "props": props})).unwrap());
+        let set_on = id(s.execute("frame.create", &json!({"x": 0, "y": 0, "width": 100, "height": 100})).unwrap());
+        set(&mut s, set_on, props.clone());
+        for f in [created, set_on] {
+            let l = s.doc().unwrap().node(f).unwrap().layout.clone().unwrap();
+            assert_eq!((l.mode, l.gap, l.padding, l.cross_align), (LayoutMode::Vertical, 8.0, [4.0; 4], CrossAlign::Center), "{props}");
+        }
+    }
+}
+
+/// Auto layout keys beside a `layout` that turns auto layout off would turn it back on: the call
+/// is refused and the layer stays as it was.
+#[test]
+fn auto_layout_keys_beside_no_auto_layout_are_refused() {
+    let mut s = Session::new();
+    let f = id(s.execute("frame.create", &json!({"x": 0, "y": 0, "width": 100, "height": 100})).unwrap());
+    for props in
+        [json!({"layout": null, "padding": 4}), json!({"layout": "none", "gap": 8, "padding": 4}), json!({"layoutMode": "NONE", "wrap": true})]
+    {
+        let e = s.execute("node.set", &json!({"id": f, "props": props})).unwrap_err().to_string();
+        assert!(e.contains("turns auto layout off"), "{props}: {e}");
+        assert!(s.doc().unwrap().node(f).unwrap().layout.is_none(), "{props}");
+        let e = s.execute("node.create", &json!({"type": "frame", "props": props})).unwrap_err().to_string();
+        assert!(e.contains("turns auto layout off"), "{props}: {e}");
+    }
+    let e = s.execute("node.set", &json!({"id": f, "props": {"layout": null, "gap": 8, "padding": 4}})).unwrap_err().to_string();
+    assert!(e.contains("`gap`, `padding` are auto layout properties, and `layout` in the same call"), "{e}");
+    let e = s.execute("node.set", &json!({"id": f, "props": {"layoutMode": "NONE", "wrap": true}})).unwrap_err().to_string();
+    assert!(e.contains("`wrap` is an auto layout property, and `layoutMode` in the same call"), "{e}");
+    // Without other auto layout keys, `layout: null` still removes it.
+    set(&mut s, f, json!({"layout": "vertical", "gap": 8}));
+    set(&mut s, f, json!({"layout": null, "name": "Plain"}));
+    assert!(s.doc().unwrap().node(f).unwrap().layout.is_none());
+}
diff --git a/crates/engine/src/cmd/props.rs b/crates/engine/src/cmd/props.rs
index c8aeef30..30f3761b 100644
--- a/crates/engine/src/cmd/props.rs
+++ b/crates/engine/src/cmd/props.rs
@@ -387,20 +387,34 @@ fn paint_none(v: &Value) -> bool {
     v.is_null() || v.as_str().is_some_and(|s| s.eq_ignore_ascii_case("none"))
 }
 
-/// The order [`apply`] takes keys in: geometry first so rotation applies to the final size, style
-/// links after the values so a link wins over values its style sets, variable bindings last so
-/// paints set in the same call don't detach them.
+/// The order [`apply`] takes keys in: geometry first so rotation applies to the final size, the
+/// auto layout mode before the keys that tune it (an object `layout` replaces the whole auto
+/// layout), style links after the values so a link wins over values its style sets, variable
+/// bindings last so paints set in the same call don't detach them.
 fn apply_order(k: &str) -> u8 {
     match k {
         "path" | "width" | "height" | "w" | "h" => 0,
-        "rotation" => 2,
-        "x" | "y" => 3,
-        "fillStyle" | "strokeStyle" | "effectStyle" | "textStyle" | "gridStyle" => 4,
-        "boundVariables" => 5,
-        _ => 1,
+        "layout" | "layoutMode" => 1,
+        "rotation" => 3,
+        "x" | "y" => 4,
+        "fillStyle" | "strokeStyle" | "effectStyle" | "textStyle" | "gridStyle" => 5,
+        "boundVariables" => 6,
+        _ => 2,
     }
 }
 
+/// Auto layout keys given beside a `layout` (or `layoutMode`) that turns auto layout off: they
+/// would turn it back on (`layout_mut`), so the call is refused rather than one of them losing.
+fn layout_keys_beside_none(cmd: &str, props: &Map<String, Value>) -> Result<()> {
+    let off = ["layout", "layoutMode"]
+        .into_iter()
+        .find(|k| props.get(*k).is_some_and(|v| v.is_null() || v.as_str().is_some_and(|s| s.eq_ignore_ascii_case("none"))));
+    let tuning: Vec<String> = props.keys().filter(|k| LAYOUT_KEYS.contains(&k.as_str())).map(|k| format!("`{k}`")).collect();
+    let Some(off) = off.filter(|_| !tuning.is_empty()) else { return Ok(()) };
+    let (what, are) = if tuning.len() == 1 { ("an auto layout property", "is") } else { ("auto layout properties", "are") };
+    Err(bad(cmd, format!("{} {are} {what}, and `{off}` in the same call turns auto layout off", tuning.join(", "))))
+}
+
 /// An explicit width (`is_w`) or height makes hugging or filling on that axis fixed, like typing
 /// into W or H.
 fn fix_axis(doc: &mut Document, id: NodeId, is_w: bool) -> Result<()> {
@@ -995,6 +1009,7 @@ fn apply_shape(cmd: &str, doc: &mut Document, id: NodeId, k: &str, v: &Value) ->
 
 /// Apply a property map to one node. `x`/`y` are relative to the parent.
 pub fn apply(cmd: &str, doc: &mut Document, id: NodeId, props: &Map<String, Value>) -> Result<()> {
+    layout_keys_beside_none(cmd, props)?;
     let mut unknown = Vec::new();
     let mut keys: Vec<(&String, &Value)> = props.iter().collect();
     keys.sort_by_key(|(k, _)| apply_order(k));
diff --git a/docs/mcp.md b/docs/mcp.md
index b4b57db1..15119f9b 100644
--- a/docs/mcp.md
+++ b/docs/mcp.md
@@ -161,7 +161,9 @@ Or in a project's `.mcp.json`:
   ignored); a layer a mask hides can't be clicked there, and a mask group's box and exports are
   the mask's (plus any layers under the mask).
 - Children of an auto-layout frame are positioned by the layout: set `layout`, `gap`, `padding`,
-  `mainAlign`, `crossAlign`, `sizingH`/`sizingV` instead of x/y. More auto layout props:
+  `mainAlign`, `crossAlign`, `sizingH`/`sizingV` instead of x/y. In one call, `layout` applies
+  before the keys that tune it, so `{"layout": {"mode": "vertical"}, "gap": 8}` keeps the gap;
+  auto layout keys beside a `layout` of `null` or `"none"` are refused. More auto layout props:
   - `sizingH` / `sizingV`: `fixed`, `hug` (auto layout frames and text) or `fill` (children in an
     auto layout flow). A child can't fill an axis its parent hugs: setting `fill` turns the parent
     `fixed` on that axis, and a parent set to `hug` turns the children that filled it `fixed`. A