diff --git a/reme/components/prompt_handler.py b/reme/components/prompt_handler.py
index 5c1a3a94..8a74a652 100644
--- a/reme/components/prompt_handler.py
+++ b/reme/components/prompt_handler.py
@@ -116,8 +116,7 @@ class PromptHandler:
         flags = {k: v for k, v in kwargs.items() if isinstance(v, bool)}
         formats = {k: v for k, v in kwargs.items() if not isinstance(v, bool)}
 
-        if flags:
-            prompt = self._apply_flag_filter(prompt, flags)
+        prompt = self._apply_flag_filter(prompt, flags)
 
         return prompt.format(**formats).strip() if formats else prompt
 
diff --git a/tests/unit/test_prompt_handler.py b/tests/unit/test_prompt_handler.py
index 2678d7dc..a07cd2c6 100644
--- a/tests/unit/test_prompt_handler.py
+++ b/tests/unit/test_prompt_handler.py
@@ -182,13 +182,18 @@ def test_flag_filter_removes_non_matching():
 def test_flag_filter_default_false():
     ph = PromptHandler()
     ph.load_prompt_dict({"p": "[debug] debug info\nbase"})
-    # When no flags are passed at all, _apply_flag_filter is not called,
-    # so flagged lines are kept as-is (including the tag text after regex sub).
-    result = ph.prompt_format("p", debug=False)
+    result = ph.prompt_format("p")
     assert "debug info" not in result
     assert "base" in result
 
 
+def test_flag_filter_defaults_false_with_format_variables():
+    ph = PromptHandler()
+    ph.load_prompt_dict({"p": "[debug] debug {name}\nhello {name}"})
+    result = ph.prompt_format("p", name="Alice")
+    assert result == "hello Alice"
+
+
 def test_flag_filter_unflagged_lines_always_kept():
     ph = PromptHandler()
     ph.load_prompt_dict({"p": "line1\nline2\nline3"})