Agent cursor: a violet pointer labelled Agent acts out control-channel and MCP commands. It glides to the command's toolbar button (or its panel) and clicks with a ripple, then to each pick (faces, edges and points projected to the screen, sketch points, a new sketch's plane, the profiles an extrude takes), then the command runs; the reply waits for it and later requests queue behind. Speed instant/normal/slow; follow camera turns to a new sketch and back on finish. View settings on the navigation bar (Show Agent Cursor, speed, follow camera; remembered, off by default); ui.agent_cursor {show, speed, follow_camera}; "animate": false per call. Tests: pick to screen mapping; scenario with the cursor on (replies wait for the animation) matching the cursor-off result

Fixes #35

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/ui-egui/src/agent_cursor.rs

@@ -0,0 +1,339 @@
+//! The agent cursor (#35): a second, clearly marked pointer that acts out what an agent does
+//! over the control channel or MCP. Before an `engine.execute` runs, the pointer glides to the
+//! command's toolbar button (or its panel when the button sits in a drop-down) and clicks it,
+//! then glides to each pick in the parameters (faces, edges and points projected to the screen,
+//! sketch points, the plane of a new sketch), and only then does the command run. The reply
+//! waits for the animation, so an agent's timing stays honest. With "follow camera" on, a new
+//! sketch turns the view to face it and finishing the sketch turns back.
+//!
+//! The pointer is drawn by the app, so screen recordings capture it. It is off by default (View
+//! settings on the navigation bar, or `ui.agent_cursor {show, speed, follow_camera}`); a call
+//! with `"animate": false` skips it.
+
+use std::collections::VecDeque;
+use std::sync::mpsc::Sender;
+
+use egui::{Color32, FontId, Pos2, Shape, Stroke, pos2, vec2};
+use serde::{Deserialize, Serialize};
+use serde_json::{Value, json};
+use solvecraft_engine::geom::{Vec2, Vec3};
+
+use crate::SolveApp;
+use crate::control::ControlResponse;
+
+/// How fast the pointer moves.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum Speed {
+    /// No animation: the command runs at once.
+    Instant,
+    #[default]
+    Normal,
+    Slow,
+}
+
+impl Speed {
+    pub const ALL: [Speed; 3] = [Speed::Instant, Speed::Normal, Speed::Slow];
+    pub fn label(self) -> &'static str {
+        match self {
+            Speed::Instant => "Instant",
+            Speed::Normal => "Normal",
+            Speed::Slow => "Slow",
+        }
+    }
+    /// Seconds to glide to a stop, and to click there.
+    fn times(self) -> (f64, f64) {
+        match self {
+            Speed::Instant => (0.0, 0.0),
+            Speed::Normal => (0.45, 0.25),
+            Speed::Slow => (0.9, 0.45),
+        }
+    }
+}
+
+/// The settings (kept with the other view settings).
+#[derive(Clone, Copy, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Settings {
+    pub show: bool,
+    pub speed: Speed,
+    pub follow_camera: bool,
+}
+
+/// A request held back while the pointer acts it out.
+pub struct Job {
+    method: String,
+    params: Value,
+    reply: Sender<ControlResponse>,
+    stops: VecDeque<Pos2>,
+    /// The leg under way: where it started and when.
+    from: Pos2,
+    started: f64,
+    /// Clicked at the current stop (waiting out the click).
+    clicked: bool,
+}
+
+/// The pointer's state.
+#[derive(Default)]
+pub struct AgentCursor {
+    pub pos: Option<Pos2>,
+    job: Option<Job>,
+    /// Click ripples: where and when.
+    ripples: Vec<(Pos2, f64)>,
+    /// The view before a followed sketch (restored when it finishes).
+    saved_view: Option<solvecraft_engine::render::Camera>,
+}
+
+impl AgentCursor {
+    /// A request is being acted out (later requests wait behind it).
+    pub fn busy(&self) -> bool {
+        self.job.is_some()
+    }
+}
+
+/// Keys whose [x, y, z] values are directions or amounts, not places to point at.
+const NOT_PLACES: [&str; 14] =
+    ["translate", "dir1", "dir2", "axis", "direction", "normal", "pull", "color", "x_dir", "y_dir", "scale", "values", "limits", "size"];
+
+/// Where the pointer goes for a command: its toolbar button (or its panel), then each pick.
+pub fn stops(app: &SolveApp, command: &str, params: &Value) -> Vec<Pos2> {
+    let mut out = Vec::new();
+    if let Some(spec) = solvecraft_engine::find_command(command) {
+        let button = crate::scenario::handle_at(&format!("toolbar:{}", spec.id))
+            .or_else(|| crate::scenario::handle_at(&format!("panel:{}:{}", spec.tab, spec.panel)));
+        out.extend(button);
+    }
+    let Some(rect) = app.viewport.rect else { return out };
+    let proj = crate::viewport::projection(app, rect);
+    for w in picks(app, command, params) {
+        if let Some(p) = proj.to_screen(w).filter(|p| rect.contains(*p)) {
+            out.push(p);
+        }
+    }
+    out
+}
+
+/// The places a command's parameters pick, in the world: [x, y, z] points (faces, edges,
+/// vertices, positions), active-sketch [x, y] points, and a new sketch's plane.
+pub fn picks(app: &SolveApp, command: &str, params: &Value) -> Vec<Vec3> {
+    let id = solvecraft_engine::find_command(command).map_or(command, |c| c.id);
+    let mut out = Vec::new();
+    if id == "sketch.create"
+        && let Some(n) = params.get("plane").and_then(Value::as_str)
+        && let Some((_, _, q)) = crate::viewport::origin_planes(app).into_iter().find(|(name, _, _)| *name == n)
+    {
+        out.push((q[0] + q[1] + q[2] + q[3]) / 4.0);
+    }
+    let st = app.session.world_state();
+    let sketch = app.session.active_sketch.and_then(|s| st.sketch(s)).map(|ss| ss.plane);
+    walk(params, None, &mut |key, v| {
+        let num = |i: usize| v.get(i).and_then(Value::as_f64).filter(|x| x.is_finite());
+        let place = !key.is_some_and(|k| NOT_PLACES.contains(&k));
+        match (v.as_array().map(Vec::len), num(0), num(1), num(2)) {
+            (Some(3), Some(x), Some(y), Some(z)) if place => out.push(Vec3::new(x, y, z)),
+            (Some(2), Some(x), Some(y), None) if place => {
+                if let Some(pl) = &sketch {
+                    out.push(pl.to_world(Vec2::new(x, y)));
+                }
+            }
+            _ => {}
+        }
+    });
+    // A profile feature without picks takes the profiles of the active (else the last) sketch:
+    // point at them.
+    if out.is_empty() && matches!(id, "solid.extrude" | "solid.revolve") {
+        let ss = app.session.active_sketch.and_then(|s| st.sketch(s)).or_else(|| st.sketches.iter().rev().find(|s| !s.profiles.is_empty()));
+        if let Some(ss) = ss {
+            out.extend(ss.profiles.iter().take(4).map(|p| ss.plane.to_world(p.region.interior_point())));
+        }
+    }
+    out
+}
+
+/// Visit every value with the key it sits under (array items inherit their array's key).
+fn walk<'a>(v: &'a Value, key: Option<&'a str>, f: &mut dyn FnMut(Option<&'a str>, &'a Value)) {
+    match v {
+        Value::Object(m) => {
+            for (k, x) in m {
+                walk(x, Some(k.as_str()), f);
+            }
+        }
+        Value::Array(a) => {
+            // A point is a leaf; a list of points or other values is walked.
+            if a.len() >= 2 && a.len() <= 3 && a.iter().all(Value::is_number) {
+                f(key, v);
+            } else {
+                for x in a {
+                    walk(x, key, f);
+                }
+            }
+        }
+        _ => {}
+    }
+}
+
+/// Take over a control request when the pointer should act it out first: returns the request
+/// back when it should simply run.
+pub fn intercept(app: &mut SolveApp, method: &str, params: &Value, reply: &Sender<ControlResponse>) -> bool {
+    let s = app.ui.agent_cursor;
+    if !s.show || s.speed == Speed::Instant || !matches!(method, "engine.execute" | "command") {
+        return false;
+    }
+    if params.get("animate").and_then(Value::as_bool) == Some(false) {
+        return false;
+    }
+    let Some(cmd) = params.get("command").or(params.get("id")).and_then(Value::as_str) else { return false };
+    let inner = params.get("params").cloned().unwrap_or(json!({}));
+    let stops: VecDeque<Pos2> = stops(app, cmd, &inner).into();
+    if stops.is_empty() {
+        return false;
+    }
+    let from = app.cursor_start();
+    app.agent.job =
+        Some(Job { method: method.to_string(), params: params.clone(), reply: reply.clone(), stops, from, started: app.now, clicked: false });
+    true
+}
+
+impl SolveApp {
+    /// Where the agent pointer starts: where it was, else the middle of the viewport.
+    fn cursor_start(&self) -> Pos2 {
+        self.agent.pos.or_else(|| self.viewport.rect.map(|r| r.center())).unwrap_or(pos2(600.0, 400.0))
+    }
+}
+
+fn ease(t: f64) -> f64 {
+    let t = t.clamp(0.0, 1.0);
+    t * t * (3.0 - 2.0 * t)
+}
+
+/// Move the pointer along; when the last stop is clicked, run the held request and reply.
+pub fn step(app: &mut SolveApp, ctx: &egui::Context) {
+    let now = app.now;
+    app.agent.ripples.retain(|(_, t)| now - t < 0.6);
+    if !app.agent.ripples.is_empty() {
+        ctx.request_repaint();
+    }
+    let (glide, click) = app.ui.agent_cursor.speed.times();
+    let Some(job) = app.agent.job.as_mut() else { return };
+    ctx.request_repaint();
+    let Some(&to) = job.stops.front() else {
+        finish(app, ctx);
+        return;
+    };
+    let t = if glide > 0.0 { (now - job.started) / glide } else { 1.0 };
+    if !job.clicked {
+        let e = ease(t) as f32;
+        app.agent.pos = Some(job.from + (to - job.from) * e);
+        if t >= 1.0 {
+            job.clicked = true;
+            job.started = now;
+            app.agent.ripples.push((to, now));
+        }
+        return;
+    }
+    if now - job.started >= click {
+        job.stops.pop_front();
+        job.from = to;
+        job.started = now;
+        job.clicked = false;
+        if job.stops.is_empty() {
+            finish(app, ctx);
+        }
+    }
+}
+
+/// Run the held request now (as a call without animation) and send its reply.
+fn finish(app: &mut SolveApp, ctx: &egui::Context) {
+    let Some(job) = app.agent.job.take() else { return };
+    let mut params = job.params;
+    params["animate"] = json!(false);
+    let cmd = params.get("command").or(params.get("id")).and_then(Value::as_str).unwrap_or_default().to_string();
+    let id = solvecraft_engine::find_command(&cmd).map_or(cmd.clone(), |c| c.id.to_string());
+    let follow = app.ui.agent_cursor.follow_camera;
+    if follow && id == "sketch.create" {
+        app.agent.saved_view = Some(app.cam);
+    }
+    let (req, _rx) = crate::control::ControlRequest::new(job.method, params);
+    let out = match crate::control::handle(app, ctx, &req) {
+        crate::control::Outcome::Done(v) => v,
+        crate::control::Outcome::Screenshot { .. } => json!({"ok": false, "error": "not a command"}),
+    };
+    let ran = out.get("ok").and_then(Value::as_bool).unwrap_or(false);
+    if follow && ran {
+        if id == "sketch.create" {
+            crate::dialogs::look_at_sketch(app);
+        } else if id == "sketch.finish"
+            && let Some(cam) = app.agent.saved_view.take()
+        {
+            app.animate_to(cam);
+        }
+    }
+    let _ = job.reply.send(out);
+}
+
+/// The pointer's colour: a violet no part of the UI uses.
+const AGENT: Color32 = Color32::from_rgb(168, 85, 247);
+
+/// Draw the pointer, its "Agent" tag and the click ripples over everything.
+pub fn paint(app: &SolveApp, ctx: &egui::Context) {
+    if !app.ui.agent_cursor.show {
+        return;
+    }
+    let Some(p) = app.agent.pos else { return };
+    let painter = ctx.layer_painter(egui::LayerId::new(egui::Order::Debug, egui::Id::new("sc_agent_cursor")));
+    for (at, t0) in &app.agent.ripples {
+        let k = ((app.now - t0) / 0.6).clamp(0.0, 1.0) as f32;
+        painter.circle_stroke(*at, 6.0 + 22.0 * k, Stroke::new(3.0 * (1.0 - k) + 0.5, AGENT.gamma_multiply(1.0 - k)));
+    }
+    // An arrow pointer, tip at `p`.
+    let pts: Vec<Pos2> =
+        [(0.0, 0.0), (0.0, 17.0), (4.5, 13.0), (7.5, 20.0), (10.5, 18.8), (7.5, 12.0), (13.0, 12.0)].iter().map(|(x, y)| p + vec2(*x, *y)).collect();
+    painter.add(Shape::convex_polygon(pts.clone(), AGENT, Stroke::NONE));
+    painter.add(Shape::closed_line(pts, Stroke::new(1.5, Color32::WHITE)));
+    let label = painter.layout_no_wrap("Agent".into(), FontId::proportional(11.0), Color32::WHITE);
+    let r = egui::Rect::from_min_size(p + vec2(15.0, 18.0), label.size() + vec2(10.0, 4.0));
+    painter.rect_filled(r, 4.0, AGENT);
+    painter.galley(r.min + vec2(5.0, 2.0), label, Color32::WHITE);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::Services;
+    use solvecraft_engine::Session;
+
+    fn app() -> SolveApp {
+        let mut s = Session::default();
+        s.execute("solid.box", &json!({"length": 40, "width": 30, "height": 20})).unwrap();
+        let mut a = SolveApp::new(s, Services::default());
+        a.viewport.rect = Some(egui::Rect::from_min_size(pos2(250.0, 120.0), vec2(1100.0, 760.0)));
+        a.fit_view();
+        a
+    }
+
+    #[test]
+    fn picks_are_the_places_in_the_parameters() {
+        let a = app();
+        // Points and lists of points, not directions or colours.
+        let p = json!({"edges": [[20, 0, 20], [40, 15, 20]], "position": [5, 5, 20], "translate": [1, 2, 3], "color": [255, 0, 0], "radius": 2});
+        let w = picks(&a, "solid.fillet", &p);
+        assert_eq!(w.len(), 3, "{w:?}");
+        assert!(w.contains(&Vec3::new(20.0, 0.0, 20.0)) && w.contains(&Vec3::new(5.0, 5.0, 20.0)));
+        // A new sketch's origin plane is a place too (the middle of its square).
+        assert_eq!(picks(&a, "sketch.create", &json!({"plane": "XY"})).len(), 1);
+    }
+
+    #[test]
+    fn picks_land_where_the_viewport_draws_them() {
+        let a = app();
+        let rect = a.viewport.rect.unwrap();
+        let proj = crate::viewport::projection(&a, rect);
+        let at = Vec3::new(20.0, 15.0, 20.0);
+        let s = stops(&a, "solid.hole", &json!({"position": [20, 15, 20], "diameter": 5}));
+        let want = proj.to_screen(at).unwrap();
+        assert!(s.iter().any(|p| p.distance(want) < 0.01), "{s:?} vs {want:?}");
+        assert!(rect.contains(want));
+        // Off-screen places are skipped rather than pointed at outside the view.
+        assert!(stops(&a, "solid.hole", &json!({"position": [1e6, 0, 0]})).iter().all(|p| rect.contains(*p)));
+    }
+}

crates/ui-egui/src/control.rs

@@ -27,6 +27,9 @@
 //! - `ui.prefs {...}`: the preferences (default_units, nav, zoom_reverse, orbit_cursor, msaa,
 //!   length_decimals, angle_decimals); returns them all
 //! - `ui.capture {action?: capture|revert|cancel}`: the Capture Position question
+//! - `ui.agent_cursor {show?, speed?: instant|normal|slow, follow_camera?}`: the agent cursor
+//!   (#35); while it is shown, `engine.execute` first glides to the command's button and picks
+//!   and replies once the command has run (`"animate": false` skips that one call)
 //! - `ui.resize {width, height}`, `app.quit`
 
 use std::sync::mpsc::Sender;
@@ -95,6 +98,22 @@ pub fn handle(app: &mut SolveApp, ctx: &egui::Context, req: &ControlRequest) ->
             }
             wrap(r)
         }
+        "ui.agent_cursor" => {
+            let s = &mut app.ui.agent_cursor;
+            if let Some(v) = p.get("show").and_then(Value::as_bool) {
+                s.show = v;
+            }
+            if let Some(v) = p.get("follow_camera").and_then(Value::as_bool) {
+                s.follow_camera = v;
+            }
+            if let Some(v) = p.get("speed") {
+                match serde_json::from_value(v.clone()) {
+                    Ok(sp) => s.speed = sp,
+                    Err(_) => return err("speed must be instant, normal or slow"),
+                }
+            }
+            ok(json!(app.ui.agent_cursor))
+        }
         "engine.script" => wrap(app.session.run_script(p).map(|v| json!(v)).map_err(|e| e.to_string())),
         "engine.commands" => wrap(app.session.execute("engine.commands", &json!({})).map_err(|e| e.to_string())),
         "document.inspect" => wrap(app.session.execute("document.inspect", p).map_err(|e| e.to_string())),

crates/ui-egui/src/lib.rs

@@ -9,6 +9,7 @@
 #![forbid(unsafe_code)]
 
 pub mod access;
+pub mod agent_cursor;
 pub mod browser;
 pub mod canvas;
 pub mod context_menu;
@@ -104,6 +105,8 @@ pub struct UiState {
     pub shown_dims: Vec<u64>,
     /// Bodies locked in the browser (no move or delete).
     pub locked_bodies: Vec<String>,
+    /// The agent cursor: shown, speed, follow camera (#35).
+    pub agent_cursor: agent_cursor::Settings,
 }
 
 impl Default for UiState {
@@ -129,6 +132,7 @@ impl Default for UiState {
             hidden_profiles: Vec::new(),
             shown_dims: Vec::new(),
             locked_bodies: Vec::new(),
+            agent_cursor: Default::default(),
         }
     }
 }
@@ -199,6 +203,8 @@ pub struct SolveApp {
     /// The modifiers of the synthetic press in progress (a Ctrl-drag keeps Ctrl while it moves).
     pub synthetic_mods: egui::Modifiers,
     control_rx: Option<Receiver<ControlRequest>>,
+    /// The agent cursor acting out control requests.
+    pub agent: agent_cursor::AgentCursor,
     pending_shots: Vec<(u64, Option<String>, std::sync::mpsc::Sender<Value>, f64)>,
     queued_shots: Vec<(u64, f64, u32)>,
     shot_token: u64,
@@ -248,6 +254,7 @@ impl SolveApp {
             synthetic: Vec::new(),
             synthetic_mods: egui::Modifiers::default(),
             control_rx: None,
+            agent: Default::default(),
             pending_shots: Vec::new(),
             queued_shots: Vec::new(),
             shot_token: 0,
@@ -653,6 +660,7 @@ impl SolveApp {
         self.now = ctx.input(|i| i.time);
         self.step_view_animation(ctx);
         self.drain_control(ctx);
+        agent_cursor::step(self, ctx);
         if !self.synthetic.is_empty() {
             ctx.request_repaint();
         }
@@ -732,13 +740,20 @@ impl SolveApp {
         shortcut_box::show(self, ui.ctx());
         keymap::show(self, ui.ctx());
         prefs::show(self, ui.ctx());
+        agent_cursor::paint(self, ui.ctx());
         self.frame_ms = now_ms() - t0;
     }
 
     fn drain_control(&mut self, ctx: &egui::Context) {
         let Some(rx) = self.control_rx.take() else { return };
-        while let Ok(req) = rx.try_recv() {
+        // While the agent cursor acts out a request, later ones wait their turn.
+        while !self.agent.busy() {
+            let Ok(req) = rx.try_recv() else { break };
             let reply = req.reply.clone();
+            if agent_cursor::intercept(self, &req.method, &req.params, &reply) {
+                ctx.request_repaint();
+                continue;
+            }
             match control::handle(self, ctx, &req) {
                 control::Outcome::Done(v) => {
                     let _ = reply.send(v);

crates/ui-egui/src/scenario.rs

@@ -9,6 +9,9 @@
 //! - `{"click": AT, "double"?, "shift"?, "ctrl"?, "button"?}`, `{"move": AT}`,
 //!   `{"drag": [AT, AT], "shift"?, "ctrl"?, "steps"?}` where AT is `[x, y]` (screen), `{"world": [x,y,z]}`
 //!   or `{"sketch": [x,y]}` (the sketch being edited)
+//! - `{"queued": "engine.execute", "params": {…}, "min_frames"?: n}`: a request sent the way an
+//!   agent's arrive (through the app's request queue, answered between frames, so the agent
+//!   cursor can act it out first); fails if the answer came in fewer than `min_frames` frames
 //! - `{"call": "ui.view", "params": {…}}`: any other control request (`fail: true` expects an
 //!   error)
 //! - `{"make_image": "pic.png"}`: a picture in the scenario's folder
@@ -112,6 +115,8 @@ pub struct Harness {
     pub dir: PathBuf,
     /// The file the next Open picker returns (a `choose_file` step).
     next_file: Rc<RefCell<Option<String>>>,
+    /// The app's request queue, opened by the first queued request.
+    queue: Option<std::sync::mpsc::Sender<ControlRequest>>,
     time: f64,
     size: egui::Vec2,
 }
@@ -139,6 +144,7 @@ impl Harness {
             output: Default::default(),
             dir: scratch_dir(),
             next_file: Rc::new(RefCell::new(None)),
+            queue: None,
             time: 0.0,
             size: egui::vec2(1600.0, 1000.0),
         };
@@ -201,6 +207,28 @@ impl Harness {
     }
 
     /// One control request, then frames until its input has been handled.
+    /// Send a request through the app's queue, as the control channel does, and run frames
+    /// until it is answered: (the reply, frames it took).
+    pub fn call_queued(&mut self, method: &str, params: Value) -> (Value, usize) {
+        let tx = self.queue.get_or_insert_with(|| {
+            let (tx, rx) = std::sync::mpsc::channel();
+            self.app.control_rx = Some(rx);
+            tx
+        });
+        let (req, rx) = ControlRequest::new(method, params);
+        if tx.send(req).is_err() {
+            return (json!({"ok": false, "error": "the request queue is closed"}), 0);
+        }
+        for n in 1..=3000 {
+            self.frame();
+            if let Ok(v) = rx.try_recv() {
+                self.settle();
+                return (v, n);
+            }
+        }
+        (json!({"ok": false, "error": "no answer in 3000 frames"}), 3000)
+    }
+
     pub fn call(&mut self, method: &str, params: Value) -> Value {
         let (req, _rx) = ControlRequest::new(method, params);
         let out = match handle(&mut self.app, &self.ctx, &req) {
@@ -328,6 +356,13 @@ impl Harness {
                 let [x1, y1] = self.at(d.get(1).unwrap_or(&Value::Null))?;
                 let steps = s.get("steps").cloned().unwrap_or(json!(8));
                 self.call("ui.drag", json!({"x0": x0, "y0": y0, "x1": x1, "y1": y1, "steps": steps, "shift": flag("shift"), "ctrl": flag("ctrl")}))
+            } else if let Some(m) = s.get("queued").and_then(Value::as_str) {
+                let (v, frames) = self.call_queued(m, s.get("params").cloned().unwrap_or(json!({})));
+                let min = s.get("min_frames").and_then(Value::as_u64).unwrap_or(0);
+                if (frames as u64) < min {
+                    return Err(format!("{m} was answered after {frames} frames: the agent cursor did not act it out ({min})"));
+                }
+                v
             } else if let Some(m) = s.get("call").and_then(Value::as_str) {
                 self.call(m, s.get("params").cloned().unwrap_or(json!({})))
             } else if s.get("note").is_some() || s.get("pending").is_some() {

crates/ui-egui/src/viewport.rs

@@ -1971,8 +1971,10 @@ fn nav_bar(app: &mut SolveApp, ui: &mut egui::Ui, rect: Rect) {
         ("home", "Home view"),
         ("perspective", "Perspective / orthographic"),
         ("style", "Visual style: shaded with edges, shaded, wireframe, shaded with hidden edges"),
-        ("settings", "Grid on/off"),
+        ("settings", "View settings: grid, ground shadow, agent cursor"),
     ];
+    let menu_id = ui.id().with("nav_view_menu");
+    let mut menu_open = ui.data(|d| d.get_temp::<bool>(menu_id)).unwrap_or(false);
     let w = items.len() as f32 * 30.0 + 10.0;
     let bar = Rect::from_center_size(pos2(rect.center().x, rect.bottom() - 22.0), vec2(w, 30.0));
     let painter = ui.painter_at(rect);
@@ -1985,7 +1987,7 @@ fn nav_bar(app: &mut SolveApp, ui: &mut egui::Ui, rect: Rect) {
             "pan" => app.viewport.nav == Some(NavMode::Pan),
             "zoom" => app.viewport.nav == Some(NavMode::Zoom),
             "perspective" => app.ui.perspective,
-            "settings" => app.ui.show_grid,
+            "settings" => menu_open,
             "spin" => app.viewport.spin,
             _ => false,
         };
@@ -2008,10 +2010,50 @@ fn nav_bar(app: &mut SolveApp, ui: &mut egui::Ui, rect: Rect) {
                 "lookat" => look_at_selection(app),
                 "style" => app.ui.visual_style = (app.ui.visual_style + 1) % 4,
                 "perspective" => app.ui.perspective = !app.ui.perspective,
-                _ => app.ui.show_grid = !app.ui.show_grid,
+                _ => menu_open = !menu_open,
+            }
+        }
+        if *icon == "settings" {
+            crate::scenario::publish_handle("nav:view", br.center());
+            if menu_open {
+                menu_open = view_menu(app, ui, br);
             }
         }
     }
+    ui.data_mut(|d| d.insert_temp(menu_id, menu_open));
+}
+
+/// The View settings above the navigation bar's last button: grid, ground shadow and the agent
+/// cursor (#35). False once it should close (a click outside it).
+fn view_menu(app: &mut SolveApp, ui: &mut egui::Ui, button: Rect) -> bool {
+    let area = egui::Area::new(egui::Id::new("sc_view_menu"))
+        .order(egui::Order::Foreground)
+        .pivot(Align2::RIGHT_BOTTOM)
+        .fixed_pos(button.right_top() - vec2(0.0, 6.0));
+    let r = area.show(ui.ctx(), |ui| {
+        egui::Frame::popup(ui.style()).show(ui, |ui| {
+            ui.set_width(220.0);
+            ui.label(egui::RichText::new("VIEW").strong().size(11.5));
+            ui.checkbox(&mut app.ui.show_grid, "Grid");
+            ui.checkbox(&mut app.ui.ground_shadow, "Ground shadow");
+            ui.separator();
+            let s = &mut app.ui.agent_cursor;
+            let show = ui.checkbox(&mut s.show, "Show Agent Cursor");
+            crate::scenario::publish_handle("view:agent_cursor", show.rect.center());
+            ui.add_enabled_ui(s.show, |ui| {
+                ui.horizontal(|ui| {
+                    ui.label("Speed");
+                    for sp in crate::agent_cursor::Speed::ALL {
+                        ui.selectable_value(&mut s.speed, sp, sp.label());
+                    }
+                });
+                ui.checkbox(&mut s.follow_camera, "Follow camera (Look At sketches)");
+            });
+        });
+    });
+    let clicked_out = ui.input(|i| i.pointer.any_pressed())
+        && ui.input(|i| i.pointer.interact_pos()).is_some_and(|p| !r.response.rect.contains(p) && !button.contains(p));
+    !clicked_out
 }
 
 #[cfg(test)]

crates/ui-egui/tests/scenarios/agent_cursor.json

@@ -0,0 +1,17 @@
+[
+  {"note": "#35: with the agent cursor on, an agent's commands are acted out (the reply waits for the pointer) and give the same result as with it off"},
+  {"call": "ui.agent_cursor", "params": {"show": true, "speed": "normal", "follow_camera": true}},
+  {"queued": "engine.execute", "params": {"command": "sketch.create", "params": {"plane": "XY"}}, "min_frames": 30},
+  {"queued": "engine.execute", "params": {"command": "sketch.rectangle.two_point", "params": {"p0": [0, 0], "p1": [40, 25]}}, "min_frames": 45},
+  {"queued": "engine.execute", "params": {"command": "sketch.finish", "params": {}}, "min_frames": 30},
+  {"queued": "engine.execute", "params": {"command": "solid.extrude", "params": {"distance": 10, "operation": "new"}}, "min_frames": 30},
+  {"expect": {"errors": 0, "bodies": 1, "volume": [10000, 1e-6]}},
+  {"note": "A call with animate: false runs at once"},
+  {"queued": "engine.execute", "params": {"command": "sketch.create", "params": {"plane": "XY"}, "animate": false}},
+  {"call": "ui.agent_cursor", "params": {"show": false}},
+  {"note": "The same steps with the cursor off: a second, identical body"},
+  {"queued": "engine.execute", "params": {"command": "sketch.rectangle.two_point", "params": {"p0": [0, 0], "p1": [40, 25]}}},
+  {"queued": "engine.execute", "params": {"command": "sketch.finish", "params": {}}},
+  {"queued": "engine.execute", "params": {"command": "solid.extrude", "params": {"distance": 10, "operation": "new"}}},
+  {"expect": {"errors": 0, "bodies": 2, "volume": [20000, 1e-6]}}
+]

docs/control-protocol.md

@@ -52,6 +52,7 @@ Commands never open dialogs when run this way. `solvecraft-cli commands` prints
 | `ui.prefs` | any of `default_units`, `nav` (`fusion`, `solidworks`, `inventor`), `zoom_reverse`, `orbit_cursor`, `msaa`, `length_decimals`, `angle_decimals` | sets preferences (kept between runs), returns them all |
 | `ui.capture` | `action?`: `capture`, `revert`, `cancel` | answers the Capture Position question (asked when a command starts or the design is saved while components were moved without capturing); without `action`, what waits |
 | `ui.window` | `action`: minimize, maximize, restore, toggle, close | what the title bar's caption buttons do (on Windows and Linux the application bar is the title bar); close asks about unsaved designs first |
+| `ui.agent_cursor` | `show` (bool), `speed`: `instant`, `normal`, `slow`, `follow_camera` (bool); all optional | the settings. While the cursor is shown, `engine.execute` first glides to the command's toolbar button and to each pick, then runs and replies; later requests wait their turn. `"animate": false` on a call skips it |
 | `ui.resize` | `width`, `height` | |
 | `app.quit` | `force?` (quit without asking about unsaved designs) | `quitting` (the window closes), `asking` (a "save changes?" prompt is open) |