diff --git a/src/ai_typewriter/config.py b/src/ai_typewriter/config.py
index fbe283b..026c30d 100644
--- a/src/ai_typewriter/config.py
+++ b/src/ai_typewriter/config.py
@@ -19,7 +19,7 @@ class AppConfig:
     request_timeout_seconds: float | None = 300.0
     copy_wait_seconds: float = 1.0
     type_delay_seconds: float = 0.0
-    math_text_format: MathTextFormat = "word_equation"
+    math_text_format: MathTextFormat = "plain"
     restore_clipboard: bool = True
     system_prompt: str = (
         "Réponds directement et de manière ultra-concise. "
@@ -43,7 +43,7 @@ def _coerce_timeout(value: Any) -> float | None:
 
 
 def _coerce_math_text_format(value: Any) -> MathTextFormat:
-    mode = str(value or "word_equation").lower().strip()
+    mode = str(value or "plain").lower().strip()
     if mode not in {"plain", "unicode", "unicode_math", "word_equation"}:
         raise ValueError("config.math_text_format doit être 'plain', 'unicode' ou 'word_equation'")
     return mode  # type: ignore[return-value]
@@ -65,7 +65,7 @@ def load_config(path: str | Path = "config.json") -> AppConfig:
         request_timeout_seconds=_coerce_timeout(data.get("request_timeout_seconds", 300)),
         copy_wait_seconds=float(data.get("copy_wait_seconds", 1)),
         type_delay_seconds=float(data.get("type_delay_seconds", 0)),
-        math_text_format=_coerce_math_text_format(data.get("math_text_format", "word_equation")),
+        math_text_format=_coerce_math_text_format(data.get("math_text_format", "plain")),
         restore_clipboard=bool(data.get("restore_clipboard", True)),
         system_prompt=str(data.get("system_prompt", AppConfig.system_prompt)),
     )