diff --git a/editor/CMakeLists.txt b/editor/CMakeLists.txt
index 1722bf4..a1e0bdd 100644
--- a/editor/CMakeLists.txt
+++ b/editor/CMakeLists.txt
@@ -190,6 +190,9 @@ target_include_directories(step65_test PRIVATE src)
 add_executable(step66_test tests/step66_test.cpp)
 target_include_directories(step66_test PRIVATE src)
 
+add_executable(step67_test tests/step67_test.cpp)
+target_include_directories(step67_test PRIVATE src)
+
 add_executable(whetstone_editor src/main.cpp)
 target_include_directories(whetstone_editor PRIVATE src)
 # find_package(SDL2 REQUIRED)  # Commented out for now to avoid build issues
diff --git a/editor/tests/step67_test.cpp b/editor/tests/step67_test.cpp
new file mode 100644
index 0000000..899222d
--- /dev/null
+++ b/editor/tests/step67_test.cpp
@@ -0,0 +1,203 @@
+// Step 67 TDD Test: Optimization annotations
+//
+// Tests optimization annotation classes and their C++ code generation:
+// 1. @Hot → C++ __attribute__((hot))
+// 2. @Cold → C++ __attribute__((cold))
+// 3. @Inline(Always) → C++ [[gnu::always_inline]]
+// 4. @Pure → C++ [[nodiscard]]
+// 5. @ConstExpr → C++ constexpr
+// 6. All optimization annotation classes exist and inherit from Annotation
+//
+// Will fail until optimization annotation classes are created and
+// CppGenerator handles them.
+
+#include <iostream>
+#include <string>
+#include <cassert>
+#include "ast/Generator.h"
+
+static bool contains(const std::string& haystack, const std::string& needle) {
+    return haystack.find(needle) != std::string::npos;
+}
+
+int main() {
+    int passed = 0;
+    int failed = 0;
+
+    // --- Test 1: HotColdAnnotation exists ---
+    {
+        HotColdAnnotation anno;
+        anno.hint = "Hot";
+        Annotation* base = &anno;
+        (void)base;
+        assert(anno.hint == "Hot" && "Should store hint");
+
+        std::cout << "Test 1 PASS: HotColdAnnotation exists" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 2: InlineAnnotation exists ---
+    {
+        InlineAnnotation anno;
+        anno.mode = "Always";
+        Annotation* base = &anno;
+        (void)base;
+        assert(anno.mode == "Always" && "Should store mode");
+
+        std::cout << "Test 2 PASS: InlineAnnotation exists" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 3: PureAnnotation exists ---
+    {
+        PureAnnotation anno;
+        Annotation* base = &anno;
+        (void)base;
+
+        std::cout << "Test 3 PASS: PureAnnotation exists" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 4: ConstExprAnnotation exists ---
+    {
+        ConstExprAnnotation anno;
+        Annotation* base = &anno;
+        (void)base;
+
+        std::cout << "Test 4 PASS: ConstExprAnnotation exists" << std::endl;
+        ++passed;
+    }
+
+    // --- Test 5: @Hot function → C++ __attribute__((hot)) ---
+    {
+        Module mod("m1", "Perf", "cpp");
+        Function* fn = new Function("f1", "hotPath");
+        PrimitiveType* retType = new PrimitiveType("t1", "void");
+        fn->setChild("returnType", retType);
+
+        HotColdAnnotation* anno = new HotColdAnnotation();
+        anno->hint = "Hot";
+        fn->addChild("annotations", anno);
+        mod.addChild("functions", fn);
+
+        CppGenerator gen;
+        std::string output = gen.generate(&mod);
+
+        assert((contains(output, "__attribute__((hot))") || contains(output, "[[likely]]")) &&
+               "@Hot should produce __attribute__((hot)) or [[likely]]");
+
+        std::cout << "Test 5 PASS: @Hot → C++ hot attribute" << std::endl;
+        ++passed;
+
+        delete anno;
+        delete retType;
+        delete fn;
+    }
+
+    // --- Test 6: @Cold function → C++ __attribute__((cold)) ---
+    {
+        Module mod("m1", "Perf", "cpp");
+        Function* fn = new Function("f1", "errorHandler");
+        PrimitiveType* retType = new PrimitiveType("t1", "void");
+        fn->setChild("returnType", retType);
+
+        HotColdAnnotation* anno = new HotColdAnnotation();
+        anno->hint = "Cold";
+        fn->addChild("annotations", anno);
+        mod.addChild("functions", fn);
+
+        CppGenerator gen;
+        std::string output = gen.generate(&mod);
+
+        assert((contains(output, "__attribute__((cold))") || contains(output, "[[unlikely]]")) &&
+               "@Cold should produce __attribute__((cold)) or [[unlikely]]");
+
+        std::cout << "Test 6 PASS: @Cold → C++ cold attribute" << std::endl;
+        ++passed;
+
+        delete anno;
+        delete retType;
+        delete fn;
+    }
+
+    // --- Test 7: @Inline(Always) → C++ always_inline ---
+    {
+        Module mod("m1", "Perf", "cpp");
+        Function* fn = new Function("f1", "fastMath");
+        PrimitiveType* retType = new PrimitiveType("t1", "int");
+        fn->setChild("returnType", retType);
+
+        InlineAnnotation* anno = new InlineAnnotation();
+        anno->mode = "Always";
+        fn->addChild("annotations", anno);
+        mod.addChild("functions", fn);
+
+        CppGenerator gen;
+        std::string output = gen.generate(&mod);
+
+        assert((contains(output, "always_inline") || contains(output, "inline")) &&
+               "@Inline(Always) should produce inline attribute");
+
+        std::cout << "Test 7 PASS: @Inline(Always) → C++ always_inline" << std::endl;
+        ++passed;
+
+        delete anno;
+        delete retType;
+        delete fn;
+    }
+
+    // --- Test 8: @Pure → C++ [[nodiscard]] ---
+    {
+        Module mod("m1", "Perf", "cpp");
+        Function* fn = new Function("f1", "pureCalc");
+        PrimitiveType* retType = new PrimitiveType("t1", "int");
+        fn->setChild("returnType", retType);
+
+        PureAnnotation* anno = new PureAnnotation();
+        fn->addChild("annotations", anno);
+        mod.addChild("functions", fn);
+
+        CppGenerator gen;
+        std::string output = gen.generate(&mod);
+
+        assert((contains(output, "[[nodiscard]]") || contains(output, "pure") ||
+                contains(output, "[[gnu::pure]]")) &&
+               "@Pure should produce [[nodiscard]] or [[gnu::pure]]");
+
+        std::cout << "Test 8 PASS: @Pure → C++ pure/nodiscard attribute" << std::endl;
+        ++passed;
+
+        delete anno;
+        delete retType;
+        delete fn;
+    }
+
+    // --- Test 9: @ConstExpr → C++ constexpr ---
+    {
+        Module mod("m1", "Perf", "cpp");
+        Function* fn = new Function("f1", "constCalc");
+        PrimitiveType* retType = new PrimitiveType("t1", "int");
+        fn->setChild("returnType", retType);
+
+        ConstExprAnnotation* anno = new ConstExprAnnotation();
+        fn->addChild("annotations", anno);
+        mod.addChild("functions", fn);
+
+        CppGenerator gen;
+        std::string output = gen.generate(&mod);
+
+        assert(contains(output, "constexpr") &&
+               "@ConstExpr should produce 'constexpr' keyword");
+
+        std::cout << "Test 9 PASS: @ConstExpr → C++ constexpr" << std::endl;
+        ++passed;
+
+        delete anno;
+        delete retType;
+        delete fn;
+    }
+
+    // --- Summary ---
+    std::cout << "\n=== Step 67 Results: " << passed << " passed, " << failed << " failed ===" << std::endl;
+    return failed > 0 ? 1 : 0;
+}