diff --git a/include/ghostty.h b/include/ghostty.h
index cd91368e4..518af3ff2 100644
--- a/include/ghostty.h
+++ b/include/ghostty.h
@@ -75,6 +75,7 @@ typedef enum {
 typedef enum {
   GHOSTTY_CLIPBOARD_STANDARD,
   GHOSTTY_CLIPBOARD_SELECTION,
+  GHOSTTY_CLIPBOARD_PRIMARY,
 } ghostty_clipboard_e;
 
 // One representation of clipboard contents. The data is binary-safe with
diff --git a/macos/Sources/Helpers/Extensions/NSPasteboard+Extension.swift b/macos/Sources/Helpers/Extensions/NSPasteboard+Extension.swift
index 5952cdb55..9dd016e74 100644
--- a/macos/Sources/Helpers/Extensions/NSPasteboard+Extension.swift
+++ b/macos/Sources/Helpers/Extensions/NSPasteboard+Extension.swift
@@ -132,7 +132,8 @@ extension NSPasteboard {
         return result
     }
 
-    /// The pasteboard for the Ghostty enum type.
+    /// The pasteboard for the Ghostty enum type. Returns nil for locations
+    /// macOS can't serve; callers report those as unsupported.
     static func ghostty(_ clipboard: ghostty_clipboard_e) -> NSPasteboard? {
         switch clipboard {
         case GHOSTTY_CLIPBOARD_STANDARD:
@@ -141,6 +142,10 @@ extension NSPasteboard {
         case GHOSTTY_CLIPBOARD_SELECTION:
             return Self.ghosttySelection
 
+        case GHOSTTY_CLIPBOARD_PRIMARY:
+            // macOS has no primary selection.
+            return nil
+
         default:
             return nil
         }
diff --git a/src/apprt/embedded.zig b/src/apprt/embedded.zig
index 7bab01257..525bc856d 100644
--- a/src/apprt/embedded.zig
+++ b/src/apprt/embedded.zig
@@ -702,7 +702,13 @@ pub const Surface = struct {
     ) bool {
         return switch (clipboard_type) {
             .standard => true,
-            .selection, .primary => self.app.opts.supports_selection_clipboard,
+            .selection => self.app.opts.supports_selection_clipboard,
+
+            // No embedder can serve the primary selection: the embedding
+            // API has no option to declare support for it, and macOS (the
+            // only GUI embedder) has no primary selection. The selection
+            // flag above covers a distinct custom pasteboard, not this.
+            .primary => false,
         };
     }
 
@@ -717,6 +723,14 @@ pub const Surface = struct {
         // completion that requires confirmation diverts into the
         // apprt confirmation flow just like a read.
         if (state == .kitty_write) {
+            // A write to a location the embedder can't serve is
+            // rejected before the transaction completes so the caller
+            // answers ENOSYS without a permission prompt, matching
+            // reads, where the embedder reports an unsupported
+            // location from the read callback. The write callback only
+            // fires after any prompt, so it is too late to reject.
+            if (!self.supportsClipboard(clipboard_type)) return .unsupported;
+
             const alloc = self.app.core_app.alloc;
             const state_ptr = try alloc.create(apprt.ClipboardRequest);
             errdefer alloc.destroy(state_ptr);
diff --git a/src/terminal/stream_terminal.zig b/src/terminal/stream_terminal.zig
index 2fe4b3043..5630570c5 100644
--- a/src/terminal/stream_terminal.zig
+++ b/src/terminal/stream_terminal.zig
@@ -3776,6 +3776,18 @@ test "kitty clipboard write result maps to response status" {
         "\x1B]5522;type=write:status=DONE\x07",
         S.responseSlice(),
     );
+
+    // A system without a primary selection answers a loc=primary write
+    // with ENOSYS, echoing the id.
+    S.reset();
+    S.write_result = .unsupported;
+    s.nextSlice("\x1B]5522;type=write:loc=primary:id=p1\x1B\\");
+    s.nextSlice("\x1B]5522;type=wdata\x1B\\");
+    try testing.expectEqual(clipboard.Location.primary, S.last_location);
+    try testing.expectEqualStrings(
+        "\x1B]5522;type=write:status=ENOSYS:id=p1\x1B\\",
+        S.responseSlice(),
+    );
 }
 
 test "kitty clipboard write without clipboard effect responds ENOSYS" {