diff --git a/src/calibre/ai/__init__.py b/src/calibre/ai/__init__.py
index 597b93cd10..f574354e42 100644
--- a/src/calibre/ai/__init__.py
+++ b/src/calibre/ai/__init__.py
@@ -35,6 +35,7 @@ class ChatMessage(NamedTuple):
 
 class ChatResponse(NamedTuple):
     content: str = ''
+    reasoning: str = ''
     cost: float = 0
     currency: str = 'USD'
     exception: Exception | None = None
diff --git a/src/calibre/ai/open_router/backend.py b/src/calibre/ai/open_router/backend.py
index 5dda6c6727..71fe8b3f85 100644
--- a/src/calibre/ai/open_router/backend.py
+++ b/src/calibre/ai/open_router/backend.py
@@ -228,6 +228,10 @@ def free_model_choice_for_text(allow_paid: bool = False) -> tuple[Model, ...]:
 
 
 def model_choice_for_text() -> Iterator[Model, ...]:
+    model_id, model_name = pref('text_model', ('', ''))
+    if m := get_available_models().get(model_id):
+        yield m
+        return
     match pref('model_choice_strategy', 'free'):
         case 'free-or-paid':
             yield from free_model_choice_for_text(allow_paid=True)
@@ -245,6 +249,21 @@ def text_chat(messages: Sequence[ChatMessage]) -> Iterator[ChatResponse]:
         yield ChatResponse(exception=e, traceback=traceback.format_exc())
     if not models:
         models = (get_available_models()['openrouter/auto'],)
+    data = {
+        'model': models[0].id,
+        'messages': [m.for_assistant() for m in messages],
+        'usage': {'include': True},
+        'stream': True,
+        'reasoning': {'enabled': True},
+    }
+    if len(models) > 1:
+        data['models'] = [m.id for m in models[1:]]
+    s = pref('reasoning_strategy')
+    match s:
+        case 'low' | 'medium' | 'high':
+            data['reasoning']['effort'] = s
+        case _:
+            data['reasoning']['enabled'] = False
 
 
 if __name__ == '__main__':
diff --git a/src/calibre/ai/open_router/config.py b/src/calibre/ai/open_router/config.py
index 4ebd19ec17..038e020a99 100644
--- a/src/calibre/ai/open_router/config.py
+++ b/src/calibre/ai/open_router/config.py
@@ -71,6 +71,10 @@ class Model(QWidget):
         l.addWidget(la), l.addWidget(b)
         b.clicked.connect(self._select_model)
 
+    def set(self, model_id: str, model_name: str) -> None:
+        self.model_id, self.model_name = model_id, model_name
+        self.la.setText(self.model_name)
+
     def _select_model(self):
         self.select_model.emit(self.model_id, self.for_text)
 
@@ -380,8 +384,9 @@ class ConfigWidget(QWidget):
         l.addRow(_('API &key:'), a)
         if key := pref('api_key'):
             a.setText(from_hex_unicode(key))
+
         self.model_strategy = ms = QComboBox(self)
-        l.addRow(_('Model choice strategy:'), ms)
+        l.addRow(_('Model &choice strategy:'), ms)
         ms.addItem(_('Free only'), 'free-only')
         ms.addItem(_('Free or paid'), 'free-or-paid')
         ms.addItem(_('High quality'), 'native')
@@ -398,6 +403,18 @@ class ConfigWidget(QWidget):
             " results, regardless of cost. Uses OpenRouter's own automatic model selection."
         ))
 
+        self.reasoning_strat = rs = QComboBox(self)
+        l.addRow(_('&Reasoning effort:'), rs)
+        rs.addItem(_('Medium'), 'medium')
+        rs.addItem(_('High'), 'high')
+        rs.addItem(_('Low'), 'low')
+        rs.addItem(_('No reasoning'), 'none')
+        if strat := pref('reasoning_strategy'):
+            rs.setCurrentIndex(max(0, rs.findData(strat)))
+        rs.setToolTip('<p>'+_(
+            'Select how much "reasoning" AI does when aswering queries. More reasoning leads to'
+            ' better quality responses at the cost of increased cost and reduced speed.'))
+
         self.text_model = tm = Model(parent=self)
         tm.select_model.connect(self.select_model)
         l.addRow(_('Model for &text tasks:'), tm)
@@ -417,9 +434,17 @@ class ConfigWidget(QWidget):
     def model_choice_strategy(self) -> str:
         return self.model_strategy.currentData()
 
+    @property
+    def reasoning_strategy(self) -> str:
+        return self.reasoning_strat.currentData()
+
     @property
     def settings(self) -> dict[str, Any]:
-        return {'api_key': as_hex_unicode(self.api_key), 'model_choice_strategy': self.model_choice_strategy}
+        ans = {'api_key': as_hex_unicode(self.api_key), 'model_choice_strategy': self.model_choice_strategy,
+               'reasoning_strategy': self.reasoning_strategy}
+        if self.text_model.model_id:
+            ans['text_model'] = (self.text_model.model_id, self.text_model.model_name)
+        return ans
 
     @property
     def is_ready_for_use(self) -> bool: