diff --git a/tests/test_mcp_tool_processes.py b/tests/test_mcp_tool_processes.py
index 189b31b..658ca9a 100644
--- a/tests/test_mcp_tool_processes.py
+++ b/tests/test_mcp_tool_processes.py
@@ -89,14 +89,34 @@ async def test_get_process_not_found_raises():
 
 @pytest.mark.asyncio
 async def test_update_process_rejects_non_process_note():
+    # Resolves share-aware now, so the patch target is get_note_for_user, which
+    # returns (note, permission).
     plain = _fake_note(id=3, note_type="note")
-    with patch("scribe.services.notes.get_note",
-               AsyncMock(return_value=plain)):
+    plain.deleted_at = None
+    with patch("scribe.services.notes.get_note_for_user",
+               AsyncMock(return_value=(plain, "owner"))):
         from scribe.mcp.tools.processes import update_process
         with pytest.raises(ValueError):
             await update_process(process_id=3, title="x")
 
 
+@pytest.mark.asyncio
+async def test_update_process_refuses_a_read_only_share_with_the_reason():
+    """An editor grant lets the holder edit someone else's process; a viewer
+    grant must be refused, and saying "not found" about a process the caller can
+    open would just send them looking for a missing id."""
+    theirs = _fake_note(id=5, user_id=9)
+    theirs.deleted_at = None
+    with patch("scribe.services.notes.get_note_for_user",
+               AsyncMock(return_value=(theirs, "viewer"))), \
+         patch("scribe.services.access.can_write_note", AsyncMock(return_value=False)), \
+         patch("scribe.services.notes.update_note", AsyncMock()) as mock_update:
+        from scribe.mcp.tools.processes import update_process
+        with pytest.raises(ValueError, match="read-only"):
+            await update_process(process_id=5, title="x")
+    mock_update.assert_not_awaited()
+
+
 def test_register_attaches_four_tools():
     from scribe.mcp.tools import processes
     names: list[str] = []