Preserve model defaults after discovery

Signed-off-by: Salman Mohammed <smohammed@squareup.com>

desktop/src/features/agents/ui/AgentConfigFields.tsx

@@ -425,7 +425,8 @@ export function AgentConfigFields({
       autoSelectedModelScopeRef.current = null;
       return;
     }
-    if ((config.model ?? "").trim().length > 0) return;
+    // Discovery fills an unset model; it must not replace an inherited default.
+    if ((config.model ?? "").trim() || fallbackModel?.trim()) return;
     if (modelDiscoveryLoading || discoveredModelOptions === null) return;
     const selectionScope = `${selectedRuntimeId}:${trimmedProvider}`;
     if (autoSelectedModelScopeRef.current === selectionScope) return;
@@ -441,6 +442,7 @@ export function AgentConfigFields({
   }, [
     config,
     discoveredModelOptions,
+    fallbackModel,
     isCustomProvider,
     modelDiscoveryLoading,
     onConfigChange,

desktop/tests/e2e/onboarding-agent-defaults.spec.ts

@@ -1234,7 +1234,7 @@ test("baked build config keeps Finish enabled without manual provider setup", as
   await expect(page.getByTestId("onboarding-finish")).toBeEnabled();
 });
 
-test("bundled Goose displays its own provider and model defaults", async ({
+test("bundled Goose preserves its defaults after model discovery", async ({
   page,
 }) => {
   await installMockBridge(
@@ -1263,6 +1263,10 @@ test("bundled Goose displays its own provider and model defaults", async ({
       bakedBuildEnv: [
         { key: "BUZZ_AGENT_PROVIDER", masked: false, value: "anthropic" },
       ],
+      discoverAgentModels: {
+        models: [{ id: "discovered-model", name: "Discovered Model" }],
+        supportsSwitching: true,
+      },
       globalAgentConfig: {
         env_vars: {},
         provider: null,
@@ -1279,6 +1283,13 @@ test("bundled Goose displays its own provider and model defaults", async ({
   await expect(page.getByTestId("global-agent-provider")).toContainText(
     "Databricks",
   );
+  // Wait for the competing catalog entry to render so this assertion cannot
+  // pass before the discovery effect has had a chance to replace the default.
+  await page.getByTestId("global-agent-model").click();
+  await expect(
+    page.getByTestId("global-agent-model-option-discovered-model"),
+  ).toBeVisible();
+  await page.keyboard.press("Escape");
   await expect(page.getByTestId("global-agent-model")).toContainText(
     "bundled-pilot-model",
   );