diff --git a/src/agent/Terminal.zig b/src/agent/Terminal.zig
index c3e11f15..fefeb323 100644
--- a/src/agent/Terminal.zig
+++ b/src/agent/Terminal.zig
@@ -5,7 +5,6 @@ const Config = lp.Config;
 const Command = lp.script.Command;
 const SlashCommand = @import("SlashCommand.zig");
 const Spinner = @import("Spinner.zig");
-const string = @import("../string.zig");
 const c = @cImport({
     @cInclude("isocline.h");
 });
@@ -428,7 +427,7 @@ fn highlighterCallback(henv: ?*c.ic_highlight_env_t, input: [*c]const u8, _: ?*a
         // ALL CAPS but unknown → typo (red); lowercase/mixed → natural language (unstyled).
         const style: ?[*:0]const u8 = if (isKnownCommand(cmd))
             style_cmd
-        else if (string.isAllUpper(cmd))
+        else if (looksLikeKeyword(cmd))
             style_err
         else
             null;
@@ -437,6 +436,14 @@ fn highlighterCallback(henv: ?*c.ic_highlight_env_t, input: [*c]const u8, _: ?*a
     }
 }
 
+fn looksLikeKeyword(s: []const u8) bool {
+    if (s.len == 0) return false;
+    for (s) |ch| {
+        if (!std.ascii.isUpper(ch) and !std.ascii.isDigit(ch) and ch != '_') return false;
+    }
+    return true;
+}
+
 fn isKnownCommand(name: []const u8) bool {
     for (Command.keywords) |kw| {
         if (std.mem.eql(u8, kw.name, name)) return true;
diff --git a/src/script/Command.zig b/src/script/Command.zig
index dca46572..34ba1aa1 100644
--- a/src/script/Command.zig
+++ b/src/script/Command.zig
@@ -599,6 +599,11 @@ fn getJsonI32(o: std.json.ObjectMap, key: []const u8, default: i32) i32 {
 
 // --- Tests ---
 
+fn testUpcase(ar: std.mem.Allocator, input: []const u8) []const u8 {
+    const out = ar.alloc(u8, input.len) catch return input;
+    return std.ascii.upperString(out, input);
+}
+
 test "parse GOTO" {
     const cmd = parse("GOTO https://example.com");
     try std.testing.expectEqualStrings("https://example.com", cmd.goto);
@@ -1188,15 +1193,7 @@ test "toToolCall: substitute callback applied to selector fields" {
     defer arena.deinit();
     const a = arena.allocator();
 
-    const upcase = struct {
-        fn f(ar: std.mem.Allocator, input: []const u8) []const u8 {
-            const out = ar.alloc(u8, input.len) catch return input;
-            for (input, 0..) |c, i| out[i] = std.ascii.toUpper(c);
-            return out;
-        }
-    }.f;
-
-    const tc = toToolCall(a, .{ .click = "abc" }, upcase).?;
+    const tc = toToolCall(a, .{ .click = "abc" }, testUpcase).?;
     try std.testing.expectEqualStrings("click", tc.name);
     try std.testing.expectEqualStrings("{\"selector\":\"ABC\"}", tc.args_json);
 }
@@ -1206,15 +1203,7 @@ test "toToolCall: type_cmd value is NOT substituted" {
     defer arena.deinit();
     const a = arena.allocator();
 
-    const upcase = struct {
-        fn f(ar: std.mem.Allocator, input: []const u8) []const u8 {
-            const out = ar.alloc(u8, input.len) catch return input;
-            for (input, 0..) |c, i| out[i] = std.ascii.toUpper(c);
-            return out;
-        }
-    }.f;
-
-    const tc = toToolCall(a, .{ .type_cmd = .{ .selector = "abc", .value = "$LP_PASSWORD" } }, upcase).?;
+    const tc = toToolCall(a, .{ .type_cmd = .{ .selector = "abc", .value = "$LP_PASSWORD" } }, testUpcase).?;
     try std.testing.expectEqualStrings("fill", tc.name);
     // selector substituted, value preserved as $LP_* reference
     try std.testing.expectEqualStrings("{\"selector\":\"ABC\",\"value\":\"$LP_PASSWORD\"}", tc.args_json);
diff --git a/src/string.zig b/src/string.zig
index 03c35bc9..c91b75d9 100644
--- a/src/string.zig
+++ b/src/string.zig
@@ -311,14 +311,6 @@ pub fn isAllWhitespace(text: []const u8) bool {
     } else true;
 }
 
-pub fn isAllUpper(s: []const u8) bool {
-    if (s.len == 0) return false;
-    for (s) |ch| {
-        if (!std.ascii.isUpper(ch) and !std.ascii.isDigit(ch) and ch != '_') return false;
-    }
-    return true;
-}
-
 // Discriminatory type that signals the bridge to use arena instead of call_arena
 // Use this for strings that need to persist beyond the current call
 // The caller can unwrap and store just the underlying .str field
@@ -341,17 +333,6 @@ fn asUint(comptime string: anytype) std.meta.Int(
 
 const testing = @import("testing.zig");
 
-test "isAllUpper" {
-    try testing.expectEqual(false, isAllUpper(""));
-    try testing.expectEqual(true, isAllUpper("GOTO"));
-    try testing.expectEqual(true, isAllUpper("ACCEPT_COOKIES"));
-    try testing.expectEqual(true, isAllUpper("X1"));
-    try testing.expectEqual(true, isAllUpper("_"));
-    try testing.expectEqual(false, isAllUpper("Goto"));
-    try testing.expectEqual(false, isAllUpper("goto"));
-    try testing.expectEqual(false, isAllUpper("GO TO"));
-}
-
 test "String" {
     const other_short = try String.init(undefined, "other_short", .{});
     const other_long = try String.init(testing.allocator, "other_long" ** 100, .{});