diff --git a/spec/archive_spec.lua b/spec/archive_spec.lua
index a71eee8..df1a912 100644
--- a/spec/archive_spec.lua
+++ b/spec/archive_spec.lua
@@ -128,4 +128,13 @@ describe('archive', function()
     assert.is_true(descs['Keep pending'])
     assert.is_true(descs['Keep recent done'])
   end)
+
+  it('persists archived tasks to disk after unload/reload', function()
+    local t = store.add({ description = 'Archived task' })
+    store.update(t.id, { status = 'done', ['end'] = '2020-01-01T00:00:00Z' })
+    pending.archive()
+    store.unload()
+    store.load()
+    assert.are.equal(0, #store.active_tasks())
+  end)
 end)
diff --git a/spec/diff_spec.lua b/spec/diff_spec.lua
index 7a73c5d..3073879 100644
--- a/spec/diff_spec.lua
+++ b/spec/diff_spec.lua
@@ -57,6 +57,28 @@ describe('diff', function()
       assert.is_nil(result[2].id)
       assert.are.equal('New task here', result[2].description)
     end)
+
+    it('inline cat: token overrides header category', function()
+      local lines = {
+        'Inbox',
+        '/1/  Buy milk cat:Work',
+      }
+      local result = diff.parse_buffer(lines)
+      assert.are.equal(2, #result)
+      assert.are.equal('task', result[2].type)
+      assert.are.equal('Work', result[2].category)
+    end)
+
+    it('inline due: token is parsed', function()
+      local lines = {
+        'Inbox',
+        '/1/  Buy milk due:2026-03-15',
+      }
+      local result = diff.parse_buffer(lines)
+      assert.are.equal(2, #result)
+      assert.are.equal('task', result[2].type)
+      assert.are.equal('2026-03-15', result[2].due)
+    end)
   end)
 
   describe('apply', function()
@@ -107,6 +129,22 @@ describe('diff', function()
       assert.are.equal('Renamed', task.description)
     end)
 
+    it('updates modified when description is renamed', function()
+      local t = store.add({ description = 'Original', category = 'Inbox' })
+      t.modified = '2020-01-01T00:00:00Z'
+      store.save()
+      local lines = {
+        'Inbox',
+        '/1/  Renamed',
+      }
+      diff.apply(lines)
+      store.unload()
+      store.load()
+      local task = store.get(1)
+      assert.are.equal('Renamed', task.description)
+      assert.is_not.equal('2020-01-01T00:00:00Z', task.modified)
+    end)
+
     it('handles duplicate ids as copies', function()
       store.add({ description = 'Original' })
       store.save()
diff --git a/spec/store_spec.lua b/spec/store_spec.lua
index 930fbc0..25b8b7c 100644
--- a/spec/store_spec.lua
+++ b/spec/store_spec.lua
@@ -121,6 +121,27 @@ describe('store', function()
       local updated = store.get(t.id)
       assert.is_not_nil(updated['end'])
     end)
+
+    it('does not overwrite id or entry', function()
+      store.load()
+      local t = store.add({ description = 'Immutable fields' })
+      local original_id = t.id
+      local original_entry = t.entry
+      store.update(t.id, { id = 999, entry = 'x' })
+      local updated = store.get(original_id)
+      assert.are.equal(original_id, updated.id)
+      assert.are.equal(original_entry, updated.entry)
+    end)
+
+    it('does not overwrite end on second completion', function()
+      store.load()
+      local t = store.add({ description = 'Complete twice' })
+      store.update(t.id, { status = 'done', ['end'] = '2026-01-15T10:00:00Z' })
+      local first_end = store.get(t.id)['end']
+      store.update(t.id, { status = 'done' })
+      local task = store.get(t.id)
+      assert.are.equal(first_end, task['end'])
+    end)
   end)
 
   describe('delete', function()