diff --git a/desktop/frontend/package.json b/desktop/frontend/package.json
index 8c975b947..a970acf74 100644
--- a/desktop/frontend/package.json
+++ b/desktop/frontend/package.json
@@ -10,9 +10,9 @@
     "check:css": "node scripts/check-css-syntax.mjs src/styles.css && node scripts/check-z-index-tokens.mjs src/styles.css",
     "test:todo-visibility": "node scripts/test-todo-visibility.mjs",
     "typecheck": "tsc --noEmit",
-    "test": "tsx src/__tests__/math-golden.test.ts && tsx src/__tests__/text-size.test.ts",
+    "test": "tsx src/__tests__/math-golden.test.ts && tsx src/__tests__/text-size.test.ts && tsx src/__tests__/provider-model-refresh.test.ts",
     "test:typecheck": "tsc --noEmit -p tsconfig.test.json",
-    "test:all": "tsc --noEmit -p tsconfig.test.json && tsx src/__tests__/math-golden.test.ts && tsx src/__tests__/text-size.test.ts"
+    "test:all": "tsc --noEmit -p tsconfig.test.json && tsx src/__tests__/math-golden.test.ts && tsx src/__tests__/text-size.test.ts && tsx src/__tests__/provider-model-refresh.test.ts"
   },
   "dependencies": {
     "@tanstack/react-virtual": "^3.14.2",
diff --git a/desktop/frontend/src/__tests__/provider-model-refresh.test.ts b/desktop/frontend/src/__tests__/provider-model-refresh.test.ts
new file mode 100644
index 000000000..120b8a1fa
--- /dev/null
+++ b/desktop/frontend/src/__tests__/provider-model-refresh.test.ts
@@ -0,0 +1,57 @@
+// Run: tsx src/__tests__/provider-model-refresh.test.ts
+
+import { mergedFetchedProviderModels, providerDefaultModel } from "../lib/providerModels";
+
+let passed = 0;
+let failed = 0;
+
+function eq(a: unknown, b: unknown, label: string) {
+  if (JSON.stringify(a) === JSON.stringify(b)) {
+    process.stdout.write(`  PASS  ${label}\n`);
+    passed += 1;
+  } else {
+    process.stdout.write(`  FAIL  ${label}: expected ${JSON.stringify(b)}, got ${JSON.stringify(a)}\n`);
+    failed += 1;
+  }
+}
+
+console.log("\nprovider model refresh");
+
+eq(
+  mergedFetchedProviderModels(["coding-pro"], ["coding-pro", "chat", "vision"]),
+  ["coding-pro", "chat", "vision"],
+  "appends discovered models without removing curated ones",
+);
+
+eq(
+  mergedFetchedProviderModels(["coding-pro"], ["coding-pro", "chat", "vision"], { preserveCurated: true }),
+  ["coding-pro"],
+  "background refresh preserves manually curated model list",
+);
+
+eq(
+  mergedFetchedProviderModels(["coding-pro"], ["chat", "vision"], { preserveCurated: true }),
+  ["coding-pro"],
+  "background refresh does not re-add deleted models",
+);
+
+eq(
+  mergedFetchedProviderModels([], ["coding-pro", "chat"], { preserveCurated: true }),
+  ["coding-pro", "chat"],
+  "background refresh can populate an empty model list",
+);
+
+eq(
+  providerDefaultModel("coding-pro", ["coding-pro", "chat"]),
+  "coding-pro",
+  "preserves current default when it remains available",
+);
+
+eq(
+  providerDefaultModel("deleted", ["coding-pro", "chat"]),
+  "coding-pro",
+  "falls back to first saved model when default is unavailable",
+);
+
+console.log(`\n${passed} passed, ${failed} failed, ${passed + failed} total`);
+if (failed > 0) process.exit(1);
diff --git a/desktop/frontend/src/components/SettingsPanel.tsx b/desktop/frontend/src/components/SettingsPanel.tsx
index 429759194..620155751 100644
--- a/desktop/frontend/src/components/SettingsPanel.tsx
+++ b/desktop/frontend/src/components/SettingsPanel.tsx
@@ -3,6 +3,7 @@ import { Check, ChevronDown } from "lucide-react";
 import { asArray } from "../lib/array";
 import { app } from "../lib/bridge";
 import { normalizeLangPref, useI18n, useT, type DictKey, type LangPref } from "../lib/i18n";
+import { mergedFetchedProviderModels, providerDefaultModel } from "../lib/providerModels";
 import { useUpdater } from "../lib/useUpdater";
 import {
   THEME_STYLES,
@@ -761,9 +762,10 @@ function ModelsSection({ s, busy, apply, backgroundApply }: ModelsSectionProps)
         try {
           const fetched = await app.FetchProviderModels(provider);
           if (fetched.length === 0) continue;
-          const currentDefault = provider.default && fetched.includes(provider.default) ? provider.default : fetched[0];
-          if (sameStringList(provider.models, fetched) && provider.default === currentDefault) continue;
-          await app.SaveProvider({ ...provider, models: fetched, default: currentDefault });
+          const models = mergedFetchedProviderModels(provider.models, fetched, { preserveCurated: true });
+          const currentDefault = providerDefaultModel(provider.default, models);
+          if (sameStringList(provider.models, models) && provider.default === currentDefault) continue;
+          await app.SaveProvider({ ...provider, models, default: currentDefault });
         } catch {
           // Background discovery is opportunistic; manual refresh shows errors.
         }
@@ -1143,11 +1145,12 @@ function ProvidersSection({ s, busy, apply }: SectionProps) {
           });
           return;
         }
-        const currentDefault = p.default && fetched.includes(p.default) ? p.default : fetched[0];
-        await app.SaveProvider({ ...p, models: fetched, default: currentDefault });
+        const models = mergedFetchedProviderModels(p.models, fetched);
+        const currentDefault = providerDefaultModel(p.default, models);
+        await app.SaveProvider({ ...p, models, default: currentDefault });
         setGroupFetchResult(group.id, {
           kind: "ok",
-          text: t("settings.fetchModelsUpdatedForProvider", { provider: group.label, n: fetched.length }),
+          text: t("settings.fetchModelsUpdatedForProvider", { provider: group.label, n: models.length }),
         });
       });
     } finally {
@@ -1172,11 +1175,12 @@ function ProvidersSection({ s, busy, apply }: SectionProps) {
         try {
           const fetched = await app.FetchProviderModels({ ...probe, apiKeyEnv });
           if (fetched.length > 0) {
-            const currentDefault = probe.default && fetched.includes(probe.default) ? probe.default : fetched[0];
-            await app.SaveProvider({ ...probe, apiKeyEnv, models: fetched, default: currentDefault });
+            const models = mergedFetchedProviderModels(probe.models, fetched, { preserveCurated: true });
+            const currentDefault = providerDefaultModel(probe.default, models);
+            await app.SaveProvider({ ...probe, apiKeyEnv, models, default: currentDefault });
             setGroupFetchResult(group.id, {
               kind: "ok",
-              text: t("settings.fetchModelsUpdatedForProvider", { provider: group.label, n: fetched.length }),
+              text: t("settings.fetchModelsUpdatedForProvider", { provider: group.label, n: models.length }),
             });
             return;
           }
diff --git a/desktop/frontend/src/lib/providerModels.ts b/desktop/frontend/src/lib/providerModels.ts
new file mode 100644
index 000000000..ca331f989
--- /dev/null
+++ b/desktop/frontend/src/lib/providerModels.ts
@@ -0,0 +1,21 @@
+export function mergedFetchedProviderModels(current: string[], fetched: string[], options: { preserveCurated?: boolean } = {}): string[] {
+  const saved = uniqueStrings(current);
+  if (options.preserveCurated && saved.length > 0) return saved;
+  return uniqueStrings([...saved, ...fetched]);
+}
+
+export function providerDefaultModel(currentDefault: string, models: string[]): string {
+  return currentDefault && models.includes(currentDefault) ? currentDefault : models[0] ?? "";
+}
+
+function uniqueStrings(values: string[]): string[] {
+  const seen = new Set<string>();
+  const out: string[] = [];
+  for (const value of values) {
+    const model = value.trim();
+    if (!model || seen.has(model)) continue;
+    seen.add(model);
+    out.push(model);
+  }
+  return out;
+}