diff --git a/kuri-mobile/src/ios/cli.zig b/kuri-mobile/src/ios/cli.zig
index 80ba31d..42d01ea 100644
--- a/kuri-mobile/src/ios/cli.zig
+++ b/kuri-mobile/src/ios/cli.zig
@@ -95,7 +95,13 @@ pub fn run(gpa: std.mem.Allocator, args: []const []const u8) !u8 {
         }
         const udid = udid_opt orelse try resolveBootedSim(gpa);
         defer if (udid_opt == null) gpa.free(udid);
-        try simctl.Sim.init(udid).screenshot(gpa, path);
+        simctl.Sim.init(udid).screenshot(gpa, path) catch |err| {
+            if (err == error.SimctlCommandFailed) {
+                io.writeStderr("screenshot failed: the target must be a booted iOS Simulator. Physical-device screenshots require XCUITest and are not supported in v1.\n");
+                return 3;
+            }
+            return err;
+        };
         return 0;
     }
     if (std.mem.eql(u8, sub, "list-apps")) {
@@ -323,7 +329,7 @@ fn printUsage() !void {
         \\  navigate  [--udid U] <url>         alias for openurl
         \\  launch    --udid U [--simulator|--device] <bundle-id>
         \\  terminate --udid U [--simulator|--device] <bundle-id>
-        \\  screenshot [--udid U] [path.png]   defaults to the booted sim if --udid omitted
+        \\  screenshot [--simulator] [--udid U] [path.png]   Simulator only; defaults to booted sim
         \\  list-apps  --udid U --simulator
         \\
         \\Simulator-only input (macOS, device-pixel coords matching screenshot):
diff --git a/kuri-mobile/src/ios/simctl.zig b/kuri-mobile/src/ios/simctl.zig
index 1dd23b1..a877c7b 100644
--- a/kuri-mobile/src/ios/simctl.zig
+++ b/kuri-mobile/src/ios/simctl.zig
@@ -12,21 +12,26 @@ pub const Sim = struct {
 
     pub fn screenshot(self: Sim, gpa: std.mem.Allocator, path: []const u8) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "io", self.udid, "screenshot", path }, 64 * 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 
     pub fn launch(self: Sim, gpa: std.mem.Allocator, bundle_id: []const u8) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "launch", self.udid, bundle_id }, 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 
     pub fn terminate(self: Sim, gpa: std.mem.Allocator, bundle_id: []const u8) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "terminate", self.udid, bundle_id }, 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 
     pub fn listApps(self: Sim, gpa: std.mem.Allocator) ![]u8 {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "listapps", self.udid }, 16 * 1024 * 1024);
+        errdefer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
         return r.stdout;
     }
 
@@ -35,20 +40,32 @@ pub const Sim = struct {
     /// you tell Safari to load a page without typing in the address bar.
     pub fn openUrl(self: Sim, gpa: std.mem.Allocator, url: []const u8) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "openurl", self.udid, url }, 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 
     pub fn boot(self: Sim, gpa: std.mem.Allocator) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "boot", self.udid }, 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 
     pub fn shutdown(self: Sim, gpa: std.mem.Allocator) !void {
         const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "shutdown", self.udid }, 1024 * 1024);
-        gpa.free(r.stdout);
+        defer gpa.free(r.stdout);
+        try ensureSuccess(r.term, r.stdout);
     }
 };
 
+fn ensureSuccess(term: i32, output: []const u8) !void {
+    if (term == 0) return;
+    if (output.len != 0) {
+        io.writeStderr(output);
+        if (output[output.len - 1] != '\n') io.writeStderr("\n");
+    }
+    return error.SimctlCommandFailed;
+}
+
 pub const SimDevice = struct {
     udid: []const u8,
     name: []const u8,
@@ -58,6 +75,7 @@ pub const SimDevice = struct {
 pub fn listDevices(gpa: std.mem.Allocator) ![]SimDevice {
     const r = try io.runCommand(gpa, &.{ "xcrun", "simctl", "list", "devices", "--json" }, 16 * 1024 * 1024);
     defer gpa.free(r.stdout);
+    try ensureSuccess(r.term, r.stdout);
 
     var parsed = try std.json.parseFromSlice(std.json.Value, gpa, r.stdout, .{});
     defer parsed.deinit();
@@ -90,6 +108,12 @@ pub fn listDevices(gpa: std.mem.Allocator) ![]SimDevice {
     return try list.toOwnedSlice(gpa);
 }
 
+test "simctl command status is not silently ignored" {
+    try ensureSuccess(0, "");
+    try std.testing.expectError(error.SimctlCommandFailed, ensureSuccess(256, "simctl failed"));
+    try std.testing.expectError(error.SimctlCommandFailed, ensureSuccess(9, "terminated"));
+}
+
 pub fn freeSimDevices(gpa: std.mem.Allocator, devs: []const SimDevice) void {
     for (devs) |d| {
         gpa.free(d.udid);