browser.visibility hides and shows sketches, bodies, construction geometry and origin items (items: ids or names, or a whole folder; visible: bool), so agents can hide helper sketches over MCP. What is hidden moved from the egui UI state into the engine session (view state: not saved, not an undo step); the desktop eye toggles and menus use it, headless renders and fit leave hidden items out, and document.inspect, sketch.inspect and ui.inspect report visibility. ui.set still accepts hiddenBodies, hiddenOrigin, hiddenSketches and shownSketches. Tests: helper sketches hide and show in the engine (hostile input changes nothing) and through MCP only

crates/ui-egui/src/lib.rs

@@ -101,9 +101,6 @@ pub struct UiState {
     pub show_grid: bool,
     pub show_origin: bool,
     pub perspective: bool,
-    pub hidden_bodies: Vec<String>,
-    /// Origin items (O, X, Y, Z, XY, XZ, YZ) and construction planes hidden one by one.
-    pub hidden_origin: Vec<String>,
     pub show_sketches: bool,
     pub palette_open: bool,
     /// Dark theme (the default); a preference kept between runs.
@@ -118,9 +115,6 @@ pub struct UiState {
     pub ground_shadow: bool,
     /// The world's up axis (Z or Y; #3): the camera, view cube, home view and ground follow it.
     pub up_axis: solvecraft_engine::render::UpAxis,
-    /// Sketches hidden one by one, and finished sketches shown although a feature uses them.
-    pub hidden_sketches: Vec<u64>,
-    pub shown_sketches: Vec<u64>,
     /// Sketches whose closed profiles are not shaded.
     pub hidden_profiles: Vec<u64>,
     /// Finished sketches whose dimensions are shown.
@@ -140,8 +134,6 @@ impl Default for UiState {
             show_grid: true,
             show_origin: true,
             perspective: false,
-            hidden_bodies: Vec::new(),
-            hidden_origin: Vec::new(),
             show_sketches: true,
             palette_open: false,
             dark: true,
@@ -150,8 +142,6 @@ impl Default for UiState {
             visual_style: 0,
             ground_shadow: true,
             up_axis: Default::default(),
-            hidden_sketches: Vec::new(),
-            shown_sketches: Vec::new(),
             hidden_profiles: Vec::new(),
             shown_dims: Vec::new(),
             locked_bodies: Vec::new(),
@@ -594,7 +584,7 @@ impl SolveApp {
     pub fn origin_visible(&self) -> bool {
         self.ui.show_origin
             || (self.dialog.as_ref().is_some_and(|d| matches!(d.kind, dialogs::Kind::Sketch))
-                && !self.session.world_state().bodies.iter().any(|b| !self.ui.hidden_bodies.contains(&b.name)))
+                && !self.session.world_state().bodies.iter().any(|b| !self.session.visibility.hidden_bodies.contains(&b.name)))
     }
 
     pub fn set_status(&mut self, s: impl Into<String>, error: bool) {