diff --git a/src/leader.zig b/src/leader.zig
index 34953ff..f9ac100 100644
--- a/src/leader.zig
+++ b/src/leader.zig
@@ -76,6 +76,10 @@ pub const Leader = struct {
         return self.mode != .idle or self.message != null;
     }
 
+    pub fn capturesInput(self: *const Leader) bool {
+        return self.mode != .idle;
+    }
+
     pub fn promptText(self: *const Leader) []const u8 {
         return self.open_prompt.items;
     }
diff --git a/src/main.zig b/src/main.zig
index 2ec91ae..dffce0b 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const input = @import("input.zig");
 const layout = @import("layout.zig");
 const leader = @import("leader.zig");
+const mobile_acceptance = @import("mobile_acceptance.zig");
 const protocol = @import("protocol.zig");
 const replay = @import("replay.zig");
 const session = @import("session.zig");
@@ -123,6 +124,7 @@ test {
     _ = input;
     _ = layout;
     _ = leader;
+    _ = mobile_acceptance;
     _ = protocol;
     _ = replay;
     _ = session;
diff --git a/src/mobile_acceptance.zig b/src/mobile_acceptance.zig
new file mode 100644
index 0000000..fae3642
--- /dev/null
+++ b/src/mobile_acceptance.zig
@@ -0,0 +1,141 @@
+const std = @import("std");
+const tui = @import("tui.zig");
+
+// Mobile ergonomic acceptance tasks guard against desktop-keyboard regressions.
+// req: input/001, input/002, input/003, input/004, input/005, testing/001, testing/002, testing/003, testing/004
+
+test {
+    _ = runMobileTask;
+}
+
+const AcceptanceError = error{
+    ForbiddenDesktopInput,
+    DirectTraceCommand,
+};
+
+fn runMobileTask(allocator: std.mem.Allocator, trace: []const u8, expected_saved: []const u8) !void {
+    try assertMobileOnlyTrace(trace);
+    const result = try tui.runTrace(allocator, .{ .width = 64, .height = 5 }, trace);
+    defer result.deinit(allocator);
+    try std.testing.expect(result.quit);
+    try std.testing.expectEqualStrings(expected_saved, result.saved_bytes.?);
+}
+
+fn assertMobileOnlyTrace(trace: []const u8) !void {
+    var lines = std.mem.splitScalar(u8, trace, '\n');
+    while (lines.next()) |line| {
+        if (line.len == 0) continue;
+        if (std.mem.startsWith(u8, line, "insert ") or
+            std.mem.eql(u8, line, "save") or
+            std.mem.eql(u8, line, "quit") or
+            std.mem.eql(u8, line, "left") or
+            std.mem.eql(u8, line, "right") or
+            std.mem.eql(u8, line, "backspace"))
+        {
+            return AcceptanceError.DirectTraceCommand;
+        }
+        if (containsForbiddenToken(line)) return AcceptanceError.ForbiddenDesktopInput;
+    }
+}
+
+fn containsForbiddenToken(line: []const u8) bool {
+    const forbidden = [_][]const u8{
+        "key escape",
+        "ctrl",
+        "control",
+        "alt",
+        "option",
+        "cmd",
+        "command-key",
+        "function",
+        "key f1",
+        "key f2",
+        "key f3",
+        "key f4",
+        "key f5",
+        "key f6",
+        "key f7",
+        "key f8",
+        "key f9",
+        "key f10",
+        "key f11",
+        "key f12",
+    };
+    for (forbidden) |token| {
+        if (std.mem.indexOf(u8, line, token) != null) return true;
+    }
+    return false;
+}
+
+test "regular: mobile trace performs code edit with leader save and quit" {
+    const trace =
+        \\open 
+        \\type call
+        \\key space
+        \\key p
+        \\key p
+        \\type arg
+        \\key right
+        \\key space
+        \\key p
+        \\key s
+        \\key space
+        \\key s
+        \\key space
+        \\key q
+        \\
+    ;
+    try runMobileTask(std.testing.allocator, trace, "call(arg)/");
+}
+
+test "regular: mobile trace edits UTF-8 and hard-to-reach braces" {
+    const trace =
+        \\open safe
+        \\type é
+        \\key backspace
+        \\key space
+        \\key p
+        \\key c
+        \\type x
+        \\key right
+        \\key space
+        \\key s
+        \\key space
+        \\key q
+        \\
+    ;
+    try runMobileTask(std.testing.allocator, trace, "{x}safe");
+}
+
+test "regular: mobile search entry is reachable and recoverable without desktop chords" {
+    const trace =
+        \\open abc
+        \\key space
+        \\key /
+        \\
+    ;
+    try assertMobileOnlyTrace(trace);
+    var client = try tui.Client.init(std.testing.allocator, .{ .width = 64, .height = 4 });
+    defer client.deinit();
+    var lines = std.mem.splitScalar(u8, trace, '\n');
+    while (lines.next()) |line| {
+        if (line.len != 0) try client.handleTraceLine(line);
+    }
+    const frame = try client.render(std.testing.allocator);
+    defer std.testing.allocator.free(frame);
+    try std.testing.expect(std.mem.indexOf(u8, frame, "search is not built") != null);
+    try std.testing.expect(!client.quit);
+    try std.testing.expectError(tui.Error.NothingSaved, client.saved());
+}
+
+test "adversarial: acceptance traces reject direct editor commands" {
+    try std.testing.expectError(AcceptanceError.DirectTraceCommand, assertMobileOnlyTrace("open abc\ninsert x\n"));
+    try std.testing.expectError(AcceptanceError.DirectTraceCommand, assertMobileOnlyTrace("open abc\nsave\n"));
+    try std.testing.expectError(AcceptanceError.DirectTraceCommand, assertMobileOnlyTrace("open abc\nquit\n"));
+}
+
+test "adversarial: acceptance traces reject forbidden desktop chords" {
+    try std.testing.expectError(AcceptanceError.ForbiddenDesktopInput, assertMobileOnlyTrace("open abc\nkey escape\n"));
+    try std.testing.expectError(AcceptanceError.ForbiddenDesktopInput, assertMobileOnlyTrace("open abc\nctrl-s\n"));
+    try std.testing.expectError(AcceptanceError.ForbiddenDesktopInput, assertMobileOnlyTrace("open abc\nkey f1\n"));
+}
diff --git a/src/tui.zig b/src/tui.zig
index 5ae7249..f6a1ba2 100644
--- a/src/tui.zig
+++ b/src/tui.zig
@@ -153,9 +153,16 @@ pub const Client = struct {
 
     pub fn handleInput(self: *Client, raw: []const u8) !void {
         if (self.quit) return Error.ClientQuit;
-        const action = try self.leader.handleEvent(input.normalize(raw));
-        defer action.deinit(self.allocator);
-        try self.applyLeaderAction(action);
+        const event = input.normalize(raw);
+        if (self.leader.capturesInput() or isLeaderTrigger(event)) {
+            const action = try self.leader.handleEvent(event);
+            defer action.deinit(self.allocator);
+            try self.applyLeaderAction(action);
+            return;
+        }
+
+        _ = try self.leader.handleEvent(event);
+        try self.applyNormalInput(event);
     }
 
     pub fn saved(self: *const Client) ![]const u8 {
@@ -167,10 +174,36 @@ pub const Client = struct {
         if (std.mem.eql(u8, key_name, "enter")) return self.handleInput("\r");
         if (std.mem.eql(u8, key_name, "backspace")) return self.handleInput("\x7f");
         if (std.mem.eql(u8, key_name, "escape")) return self.handleInput("\x1b");
+        if (std.mem.eql(u8, key_name, "left")) return self.handleInput("\x1b[D");
+        if (std.mem.eql(u8, key_name, "right")) return self.handleInput("\x1b[C");
         if (key_name.len == 1) return self.handleInput(key_name);
         return Error.UnknownTraceEvent;
     }
 
+    fn isLeaderTrigger(event: input.Event) bool {
+        return switch (event) {
+            .key => |key| key == .space,
+            else => false,
+        };
+    }
+
+    fn applyNormalInput(self: *Client, event: input.Event) !void {
+        switch (event) {
+            .text => |text| {
+                const line = try std.fmt.allocPrint(self.allocator, "insert {s}", .{text});
+                defer self.allocator.free(line);
+                try self.applyProtocolCommand(line);
+            },
+            .key => |key| switch (key) {
+                .backspace => try self.applyProtocol("command delete_backward"),
+                .arrow_left => try self.applyProtocol("command move_left"),
+                .arrow_right => try self.applyProtocol("command move_right"),
+                else => {},
+            },
+            .unknown => {},
+        }
+    }
+
     fn applyLeaderAction(self: *Client, action: leader_mod.Action) !void {
         switch (action) {
             .none => {},