diff --git a/SPECGAPS.md b/SPECGAPS.md
index 5c8f921..8f5b902 100644
--- a/SPECGAPS.md
+++ b/SPECGAPS.md
@@ -131,7 +131,7 @@ All reconciled to follow code. Specs must be self-consistent and match code.
 | D1-14 | ~~ReplaceMediaFileSideEffects~~ | engine_side_effects.allium:128-134 | **Resolved:** 3 tests added in `media_test.exs` — `replace_media_file/2` copies the new image over the existing path, updates the row (checksum/size/width/height), and regenerates all thumbnails synchronously (present immediately after the call, no `.bak` backup left); identical-checksum replace is a no-op (`{:ok, nil}`); unknown media id returns `{:error, :not_found}` |
 | D1-15 | ~~Drag-and-drop image chain~~ | action_patterns.allium:84-103 | **Resolved:** the chain had no handler — added `BDS.Desktop.ShellLive.EditorImageDrop` (`import_and_link/3` runs steps 1-4: import media + synchronous thumbnails + link to post + return `![](bds-media://id)` markdown; `enrich/3` runs background steps 5-6: AI analysis auto-applied with no modal + auto-translate cascade when `do_not_translate == false`). `PostEditor.handle_event("editor_image_dropped", ...)` runs the synchronous chain (works offline since import isn't AI), pushes the cursor insert, and spawns `enrich` only when airplane mode is off. MonacoEditor JS hook captures image drops on the editor surface and pushes the file path (`phx-target={@myself}` routes the hook event to the component); i18n for de/fr/it/es. 3 tests added (module chain incl. thumbnails+link+markdown, non-image link form, full LiveView drop in airplane mode asserting import/link/insert with no AI metadata). |
 | D1-16 | ~~DebouncedPersistence (5s)~~ | embedding.allium:213-217 | **Resolved:** 3 tests added in `embeddings_test.exs` (DebouncedPersistence describe): `Index.put/3` schedules a per-project save `timer` with ~5s remaining (>4000ms, <=5000ms) instead of writing immediately (no `embeddings.usearch` on disk yet); rapid `put`s coalesce (each reschedules the single timer, the previous timer is cancelled so `Process.read_timer` returns false, and still no file after two writes); when the `{:save, project_id}` debounce message fires the index is persisted to disk and the pending `timer` cleared. The coalescing test exposed a real bug: `handle_call({:put, ...})` replaced the stored entry with `build_entry/2`'s fresh `timer: nil` entry before `schedule_save/2` ran, orphaning the previous debounce timer (left to fire a redundant save) instead of cancelling it; fixed via `cancel_pending_save/2` so bulk `put`s collapse to one deferred write |
-| D1-17 | Protected categories cannot be deleted | editor_settings.allium:81-84 | Write test: article/aside/page/picture deletion rejected |
+| D1-17 | ~~Protected categories cannot be deleted~~ | editor_settings.allium:81-84 | **Resolved:** 5 tests added in managed_categories_test.exs covering protected_category?/1 classification and remove_category/4 rejection for all 4 protected categories (article, aside, page, picture) plus non-protected deletion allowed |
 | D1-18 | HomeItemProtection (menu) | editor_misc.allium:206-209 | Write test: cannot move/reorder/delete Home |
 
 ### D2. No Test Coverage (MEDIUM priority — rules/behaviors)
diff --git a/test/bds/desktop/managed_categories_test.exs b/test/bds/desktop/managed_categories_test.exs
new file mode 100644
index 0000000..a8d1761
--- /dev/null
+++ b/test/bds/desktop/managed_categories_test.exs
@@ -0,0 +1,107 @@
+defmodule BDS.Desktop.ShellLive.SettingsEditor.ManagedCategoriesTest do
+  use ExUnit.Case, async: false
+
+  alias BDS.Desktop.ShellLive.SettingsEditor.ManagedCategories
+
+  describe "protected_category?/1" do
+    test "returns true for article, aside, page, picture" do
+      assert ManagedCategories.protected_category?("article")
+      assert ManagedCategories.protected_category?("aside")
+      assert ManagedCategories.protected_category?("page")
+      assert ManagedCategories.protected_category?("picture")
+    end
+
+    test "returns false for non-protected categories" do
+      refute ManagedCategories.protected_category?("news")
+      refute ManagedCategories.protected_category?("links")
+      refute ManagedCategories.protected_category?("random")
+    end
+  end
+
+  describe "remove_category/4" do
+    setup do
+      :ok = Ecto.Adapters.SQL.Sandbox.checkout(BDS.Repo)
+      temp_dir =
+        Path.join(System.tmp_dir!(), "bds-managed-categories-#{System.unique_integer([:positive])}")
+
+      File.mkdir_p!(temp_dir)
+
+      on_exit(fn -> File.rm_rf(temp_dir) end)
+
+      {:ok, project} =
+        BDS.Projects.create_project(%{name: "ProtectedCategories", data_path: temp_dir})
+
+      %{project: project, temp_dir: temp_dir}
+    end
+
+    test "rejects deletion of protected category with error output", %{project: project} do
+      socket = %{assigns: %{projects: %{active_project_id: project.id}, workbench: nil}}
+
+      append_output = fn _socket, _title, _msg, _nil, _kind ->
+        send(self(), :error_appended)
+        socket
+      end
+
+      ManagedCategories.remove_category(
+        socket,
+        "article",
+        fn s, _wb -> s end,
+        append_output
+      )
+
+      assert_received :error_appended
+    end
+
+    test "rejects deletion of all protected categories", %{project: project} do
+      socket = %{assigns: %{projects: %{active_project_id: project.id}, workbench: nil}}
+
+      for cat <- ["article", "aside", "page", "picture"] do
+        append_output = fn _socket, _title, _msg, _nil, _kind ->
+          send(self(), {:rejected, cat})
+          socket
+        end
+
+        ManagedCategories.remove_category(
+          socket,
+          cat,
+          fn s, _wb -> s end,
+          append_output
+        )
+
+        assert_received {:rejected, ^cat}
+      end
+    end
+
+    test "allows deletion of non-protected category via Metadata.remove_category", %{
+      project: project
+    } do
+      socket = %{
+        assigns: %{
+          projects: %{active_project_id: project.id},
+          workbench: nil
+        }
+      }
+
+      BDS.Metadata.add_category(project.id, "test-cat")
+      assert {:ok, meta} = BDS.Metadata.get_project_metadata(project.id)
+      assert "test-cat" in meta.categories
+
+      append_output = fn _socket, _title, _msg, _nil, _kind ->
+        send(self(), :error_called)
+        socket
+      end
+
+      ManagedCategories.remove_category(
+        socket,
+        "test-cat",
+        fn s, _wb -> s end,
+        append_output
+      )
+
+      refute_received :error_called
+
+      assert {:ok, meta} = BDS.Metadata.get_project_metadata(project.id)
+      refute "test-cat" in meta.categories
+    end
+  end
+end