fix(models): preserve keys after reverted connection edits (#6813)

frontend/src/components/workspace/settings/model-settings-page.tsx

@@ -212,7 +212,6 @@ function ModelEditor({
   const [draft, setDraft] = useState(() => modelDraft(model));
   const [key, setKey] = useState("");
   const [clearKey, setClearKey] = useState(false);
-  const [connectionChanged, setConnectionChanged] = useState(false);
   const [pending, setPending] = useState(false);
   const [result, setResult] = useState("");
   const active = useRef(true);
@@ -229,7 +228,7 @@ function ModelEditor({
     model?.provider === draft.provider &&
     (draft.provider !== "openai-compatible" ||
       model?.base_url === draft.base_url);
-  const canKeepKey = sameConnection && !connectionChanged && model?.has_api_key;
+  const canKeepKey = sameConnection && model?.has_api_key;
   const requiresKey =
     provider?.requires_api_key ?? draft.provider !== "openai-compatible";
   const missingKey = requiresKey && ((!key.trim() && !canKeepKey) || clearKey);
@@ -246,7 +245,6 @@ function ModelEditor({
       ...(value === "openai-compatible" ? { base_url: "" } : {}),
     });
     setKey("");
-    setConnectionChanged(true);
     setClearKey(false);
     setResult("");
     abort.current?.abort();
@@ -255,11 +253,7 @@ function ModelEditor({
     return {
       config: {
         ...draft,
-        ...(clearKey || (connectionChanged && !key)
-          ? { api_key: "" }
-          : key
-            ? { api_key: key }
-            : {}),
+        ...(clearKey ? { api_key: "" } : key ? { api_key: key } : {}),
       },
       expected_revision: model?.revision ?? null,
     };
@@ -345,14 +339,13 @@ function ModelEditor({
                     onChange={(e) => {
                       setDraft({ ...draft, base_url: e.target.value });
                       setKey("");
-                      setConnectionChanged(true);
                       setClearKey(false);
                       setResult("");
                     }}
                   />
                 </label>
               )}
-              {model && (connectionChanged || !sameConnection) && (
+              {model && !sameConnection && (
                 <p role="status">{text.providerChanged}</p>
               )}
               <label className="block space-y-1">

frontend/tests/unit/components/workspace/settings/model-settings-page.dom.test.tsx

@@ -264,6 +264,27 @@ test("switching providers clears test status and cannot reuse a saved key", asyn
   ).not.toHaveProperty("base_url");
 });
 
+test("reverting a provider switch preserves the saved key", async () => {
+  rs.mocked(loadManagedModels).mockResolvedValue({
+    models: [{ ...existing, provider: "openai", base_url: null }],
+  });
+  mount();
+  fireEvent.click(await screen.findByRole("button", { name: "Edit model" }));
+  await selectProvider("Anthropic");
+  await selectProvider("OpenAI");
+
+  expect(screen.queryByText(enUS.settings.models.providerChanged)).toBeNull();
+  expect(
+    screen.getByPlaceholderText(enUS.settings.models.keepKey),
+  ).toBeTruthy();
+
+  fireEvent.click(screen.getByRole("button", { name: "Save" }));
+  await waitFor(() => expect(saveManagedModel).toHaveBeenCalledTimes(1));
+  expect(
+    rs.mocked(saveManagedModel).mock.calls[0]![0].config,
+  ).not.toHaveProperty("api_key");
+});
+
 test("custom endpoint is separate and allows no authentication", async () => {
   mount();
   await waitFor(() =>
@@ -289,6 +310,29 @@ test("custom endpoint is separate and allows no authentication", async () => {
   });
 });
 
+test("reverting a custom endpoint edit preserves the saved key", async () => {
+  mount();
+  fireEvent.click(await screen.findByRole("button", { name: "Edit model" }));
+  const endpoint = screen.getByLabelText("Base URL");
+  fireEvent.change(endpoint, {
+    target: { value: "https://other.example.com/v1" },
+  });
+  fireEvent.change(endpoint, {
+    target: { value: existing.base_url },
+  });
+
+  expect(screen.queryByText(enUS.settings.models.providerChanged)).toBeNull();
+  expect(
+    screen.getByPlaceholderText(enUS.settings.models.keepKey),
+  ).toBeTruthy();
+
+  fireEvent.click(screen.getByRole("button", { name: "Save" }));
+  await waitFor(() => expect(saveManagedModel).toHaveBeenCalledTimes(1));
+  expect(
+    rs.mocked(saveManagedModel).mock.calls[0]![0].config,
+  ).not.toHaveProperty("api_key");
+});
+
 test("preset edits retain stable ID, leave key blank and preserve advanced overrides", async () => {
   rs.mocked(loadManagedModels).mockResolvedValue({
     models: [