fix(model-switch): prevent stale Ollama credentials after provider switch

cli.py

@@ -5804,12 +5804,15 @@ def _apply_model_switch_result(self, result, persist_global: bool) -> None:
         self.model = result.new_model
         self.provider = result.target_provider
         self.requested_provider = result.target_provider
+        # Always overwrite explicit overrides so stale credentials from the
+        # previous provider (e.g. Ollama api_key/base_url) don't leak into
+        # the new provider's credential resolution on the next turn.
+        self._explicit_api_key = result.api_key
+        self._explicit_base_url = result.base_url
         if result.api_key:
             self.api_key = result.api_key
-            self._explicit_api_key = result.api_key
         if result.base_url:
             self.base_url = result.base_url
-            self._explicit_base_url = result.base_url
         if result.api_mode:
             self.api_mode = result.api_mode
 
@@ -6027,12 +6030,15 @@ def _handle_model_switch(self, cmd_original: str):
         self.model = result.new_model
         self.provider = result.target_provider
         self.requested_provider = result.target_provider
+        # Always overwrite explicit overrides so stale credentials from the
+        # previous provider (e.g. Ollama api_key/base_url) don't leak into
+        # the new provider's credential resolution on the next turn.
+        self._explicit_api_key = result.api_key
+        self._explicit_base_url = result.base_url
         if result.api_key:
             self.api_key = result.api_key
-            self._explicit_api_key = result.api_key
         if result.base_url:
             self.base_url = result.base_url
-            self._explicit_base_url = result.base_url
         if result.api_mode:
             self.api_mode = result.api_mode
 
@@ -10443,7 +10449,11 @@ def handle_enter(event):
 
             # --- /model picker modal ---
             if self._model_picker_state:
-                self._handle_model_picker_selection()
+                try:
+                    self._handle_model_picker_selection()
+                except Exception as _exc:
+                    _cprint(f"  ✗ Model selection failed: {_exc}")
+                    self._close_model_picker()
                 event.app.current_buffer.reset()
                 event.app.invalidate()
                 return

run_agent.py

@@ -2386,7 +2386,13 @@ def switch_model(self, new_model, new_provider, api_key='', base_url='', api_mod
         # ── Swap core runtime fields ──
         self.model = new_model
         self.provider = new_provider
-        self.base_url = base_url or self.base_url
+        # Use new base_url when provided; only fall back to current when the
+        # new provider genuinely has no endpoint (e.g. native SDK providers).
+        # Without this guard the old provider's URL (e.g. Ollama's localhost
+        # address) would persist silently after switching to a cloud provider
+        # that returns an empty base_url string.
+        if base_url:
+            self.base_url = base_url
         self.api_mode = api_mode
         # Invalidate transport cache — new api_mode may need a different transport
         if hasattr(self, "_transport_cache"):