diff --git a/assets/shaders/fxaa.frag.glsl b/assets/shaders/fxaa.frag.glsl
index df35aaa0..158f2f98 100644
--- a/assets/shaders/fxaa.frag.glsl
+++ b/assets/shaders/fxaa.frag.glsl
@@ -2,7 +2,7 @@
 
 // FXAA 3.11 — Fast Approximate Anti-Aliasing post-process pass.
 // Reads the resolved scene color and outputs a smoothed result.
-// Push constant: rcpFrame = vec2(1/width, 1/height).
+// Push constant: rcpFrame = vec2(1/width, 1/height), sharpness (0=off, 2=max), unused.
 
 layout(set = 0, binding = 0) uniform sampler2D uScene;
 
@@ -10,7 +10,9 @@ layout(location = 0) in vec2 TexCoord;
 layout(location = 0) out vec4 outColor;
 
 layout(push_constant) uniform PC {
-    vec2 rcpFrame;
+    vec2  rcpFrame;
+    float sharpness;  // 0 = no sharpen, 2 = max (matches FSR2 RCAS range)
+    float _pad;
 } pc;
 
 // Quality tuning
@@ -128,5 +130,20 @@ void main() {
     if ( horzSpan) finalUV.y += pixelOffsetFinal * lengthSign;
     if (!horzSpan) finalUV.x += pixelOffsetFinal * lengthSign;
 
-    outColor = vec4(texture(uScene, finalUV).rgb, 1.0);
+    vec3 fxaaResult = texture(uScene, finalUV).rgb;
+
+    // Post-FXAA contrast-adaptive sharpening (unsharp mask).
+    // Counteracts FXAA's sub-pixel blur when sharpness > 0.
+    if (pc.sharpness > 0.0) {
+        vec2 r = pc.rcpFrame;
+        vec3 blur = (texture(uScene, uv + vec2(-r.x, 0)).rgb
+                   + texture(uScene, uv + vec2( r.x, 0)).rgb
+                   + texture(uScene, uv + vec2(0, -r.y)).rgb
+                   + texture(uScene, uv + vec2(0,  r.y)).rgb) * 0.25;
+        // scale sharpness from [0,2] to a modest [0, 0.3] boost factor
+        float s = pc.sharpness * 0.15;
+        fxaaResult = clamp(fxaaResult + s * (fxaaResult - blur), 0.0, 1.0);
+    }
+
+    outColor = vec4(fxaaResult, 1.0);
 }
diff --git a/assets/shaders/fxaa.frag.spv b/assets/shaders/fxaa.frag.spv
new file mode 100644
index 00000000..7803f3e2
Binary files /dev/null and b/assets/shaders/fxaa.frag.spv differ
diff --git a/src/rendering/renderer.cpp b/src/rendering/renderer.cpp
index f9ce69cd..8dcf724c 100644
--- a/src/rendering/renderer.cpp
+++ b/src/rendering/renderer.cpp
@@ -4968,11 +4968,11 @@ bool Renderer::initFXAAResources() {
     write.pImageInfo = &imgInfo;
     vkUpdateDescriptorSets(device, 1, &write, 0, nullptr);
 
-    // Pipeline layout — push constant holds vec2 rcpFrame
+    // Pipeline layout — push constant holds vec4(rcpFrame.xy, sharpness, pad)
     VkPushConstantRange pc{};
     pc.stageFlags = VK_SHADER_STAGE_FRAGMENT_BIT;
     pc.offset = 0;
-    pc.size = 8;  // vec2
+    pc.size = 16;  // vec4
     VkPipelineLayoutCreateInfo plCI{};
     plCI.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
     plCI.setLayoutCount = 1;
@@ -5044,19 +5044,31 @@ void Renderer::renderFXAAPass() {
     vkCmdBindDescriptorSets(currentCmd, VK_PIPELINE_BIND_POINT_GRAPHICS,
                             fxaa_.pipelineLayout, 0, 1, &fxaa_.descSet, 0, nullptr);
 
-    // Push rcpFrame = vec2(1/width, 1/height)
-    float rcpFrame[2] = {
+    // Pass rcpFrame + sharpness (vec4, 16 bytes).
+    // When FSR2/FSR3 is active alongside FXAA, forward FSR2's sharpness so the
+    // post-FXAA unsharp-mask step restores the crispness that FXAA's blur removes.
+    float sharpness = fsr2_.enabled ? fsr2_.sharpness : 0.0f;
+    float pc[4] = {
         1.0f / static_cast<float>(ext.width),
-        1.0f / static_cast<float>(ext.height)
+        1.0f / static_cast<float>(ext.height),
+        sharpness,
+        0.0f
     };
     vkCmdPushConstants(currentCmd, fxaa_.pipelineLayout,
-                       VK_SHADER_STAGE_FRAGMENT_BIT, 0, 8, rcpFrame);
+                       VK_SHADER_STAGE_FRAGMENT_BIT, 0, 16, pc);
 
     vkCmdDraw(currentCmd, 3, 1, 0, 0);  // fullscreen triangle
 }
 
 void Renderer::setFXAAEnabled(bool enabled) {
     if (fxaa_.enabled == enabled) return;
+    // FXAA is a post-process AA pass intended to supplement FSR temporal output.
+    // It conflicts with MSAA (which resolves AA during the scene render pass), so
+    // refuse to enable FXAA when hardware MSAA is active.
+    if (enabled && vkCtx && vkCtx->getMsaaSamples() > VK_SAMPLE_COUNT_1_BIT) {
+        LOG_INFO("FXAA: blocked while MSAA is active — disable MSAA first");
+        return;
+    }
     fxaa_.enabled = enabled;
     if (!enabled) {
         fxaa_.needsRecreate = true;  // defer destruction to next beginFrame()