diff --git a/plugins/_desktop/AGENTS.md b/plugins/_desktop/AGENTS.md
index 5fc6f449c..f3dc67d12 100644
--- a/plugins/_desktop/AGENTS.md
+++ b/plugins/_desktop/AGENTS.md
@@ -17,7 +17,7 @@
 - Keep desktop state injected into prompts accurate and bounded.
 - Do not expose desktop routes without the expected auth protections.
 - Keep Desktop host visibility tied to an attached modal or canvas host; modal cleanup may preserve the iframe in keepalive, but must not leave stale modal mode behind.
-- Keep Markdown and plain text file open-with handling routed to the Editor surface through the desktop intent bridge; Desktop owns the Xfce launcher/MIME setup, while Editor owns `.md` and `.txt` editing.
+- Keep LibreOffice Writer as the default handler for Markdown and plain text files; keep Agent Zero Editor available as a secondary Open With target through the desktop intent bridge.
 
 ## Work Guidance
 
diff --git a/plugins/_desktop/helpers/desktop_session.py b/plugins/_desktop/helpers/desktop_session.py
index efacb2c41..4acdab0cc 100644
--- a/plugins/_desktop/helpers/desktop_session.py
+++ b/plugins/_desktop/helpers/desktop_session.py
@@ -79,6 +79,7 @@ URL_INTENT_MAX_ITEMS = 50
 URL_INTENT_MAX_LENGTH = 8192
 URL_HANDLER_DESKTOP_ID = "agent-zero-browser.desktop"
 EDITOR_HANDLER_DESKTOP_ID = "agent-zero-editor.desktop"
+WRITER_HANDLER_DESKTOP_ID = "libreoffice-writer.desktop"
 SHUTDOWN_HANDLER_DESKTOP_ID = "agent-zero-shutdown.desktop"
 SHUTDOWN_PANEL_LAUNCHER_ID = SHUTDOWN_HANDLER_DESKTOP_ID
 SHUTDOWN_CONFIRM_SECONDS = 8
@@ -2197,15 +2198,19 @@ def _editor_text_handler_mime_types() -> tuple[str, ...]:
 
 def _write_mimeapps_defaults(path: Path, url_desktop_id: str, editor_desktop_id: str) -> None:
     url_associations = ";".join([url_desktop_id, ""])
-    editor_associations = ";".join([editor_desktop_id, ""])
+    # LibreOffice Writer stays the default so double-clicks keep the user (and
+    # agents) inside the Desktop; the Agent Zero Editor remains an "Open With"
+    # option. When Writer's desktop entry is missing, xdg falls back through
+    # the added associations to the editor.
+    text_associations = ";".join([WRITER_HANDLER_DESKTOP_ID, editor_desktop_id, ""])
     lines = [
         "[Default Applications]",
         *(f"{mime_type}={url_desktop_id}" for mime_type in _url_handler_mime_types()),
-        *(f"{mime_type}={editor_desktop_id}" for mime_type in _editor_text_handler_mime_types()),
+        *(f"{mime_type}={WRITER_HANDLER_DESKTOP_ID}" for mime_type in _editor_text_handler_mime_types()),
         "",
         "[Added Associations]",
         *(f"{mime_type}={url_associations}" for mime_type in _url_handler_mime_types()),
-        *(f"{mime_type}={editor_associations}" for mime_type in _editor_text_handler_mime_types()),
+        *(f"{mime_type}={text_associations}" for mime_type in _editor_text_handler_mime_types()),
         "",
     ]
     path.parent.mkdir(parents=True, exist_ok=True)
diff --git a/tests/test_office_canvas_setup.py b/tests/test_office_canvas_setup.py
index 404e09c5e..6d29c36d0 100644
--- a/tests/test_office_canvas_setup.py
+++ b/tests/test_office_canvas_setup.py
@@ -608,6 +608,12 @@ def test_desktop_text_open_with_routes_to_editor_surface():
     assert "handleEditorUrlIntent" in editor_store
     assert 'openLatestSurface("editor"' in editor_store
 
+    # Text files default to LibreOffice Writer inside the Desktop; the Agent
+    # Zero Editor stays available as a secondary "Open With" association.
+    assert 'WRITER_HANDLER_DESKTOP_ID = "libreoffice-writer.desktop"' in desktop_session
+    assert "{mime_type}={WRITER_HANDLER_DESKTOP_ID}" in desktop_session
+    assert "[WRITER_HANDLER_DESKTOP_ID, editor_desktop_id, " in desktop_session
+
     # The browser surface must not claim a0-editor: intents, otherwise the
     # editor "Open With" handler lands on an unloadable about:blank page.
     assert "function isWebUrlIntent" in browser_store