diff --git a/apps/web/src/appSettings.test.ts b/apps/web/src/appSettings.test.ts
index 40130ecb5a39c5d5086a357100326d62130dafbf..6c6cbac495f68b77cad8cf4b43189d606bc4dce1 100644
--- a/apps/web/src/appSettings.test.ts
+++ b/apps/web/src/appSettings.test.ts
@@ -1,6 +1,11 @@
 import { describe, expect, it } from "vitest";
 
-import { getAppModelOptions, getSlashModelOptions, normalizeCustomModelSlugs } from "./appSettings";
+import {
+  getAppModelOptions,
+  getSlashModelOptions,
+  normalizeCustomModelSlugs,
+  resolveAppModelSelection,
+} from "./appSettings";
 
 describe("normalizeCustomModelSlugs", () => {
   it("normalizes aliases, removes built-ins, and deduplicates values", () => {
@@ -42,6 +47,18 @@ describe("getAppModelOptions", () => {
   });
 });
 
+describe("resolveAppModelSelection", () => {
+  it("preserves saved custom model slugs instead of falling back to the default", () => {
+    expect(resolveAppModelSelection("codex", ["galapagos-alpha"], "galapagos-alpha")).toBe(
+      "galapagos-alpha",
+    );
+  });
+
+  it("falls back to the provider default when no model is selected", () => {
+    expect(resolveAppModelSelection("codex", [], "")).toBe("gpt-5.4");
+  });
+});
+
 describe("getSlashModelOptions", () => {
   it("includes saved custom model slugs for /model command suggestions", () => {
     const options = getSlashModelOptions(
diff --git a/apps/web/src/appSettings.ts b/apps/web/src/appSettings.ts
index 876153ce778bd867dc629851739665f080ae6518..5ed218fb254e751012d2bd5e5d00ca7e8e02469e 100644
--- a/apps/web/src/appSettings.ts
+++ b/apps/web/src/appSettings.ts
@@ -1,7 +1,7 @@
 import { useCallback, useSyncExternalStore } from "react";
 import { Option, Schema } from "effect";
 import { type ProviderKind } from "@t3tools/contracts";
-import { getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
+import { getDefaultModel, getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
 
 const APP_SETTINGS_STORAGE_KEY = "t3code:app-settings:v1";
 const MAX_CUSTOM_MODEL_COUNT = 32;
@@ -111,6 +111,38 @@ export function getAppModelOptions(
   return options;
 }
 
+export function resolveAppModelSelection(
+  provider: ProviderKind,
+  customModels: readonly string[],
+  selectedModel: string | null | undefined,
+): string {
+  const options = getAppModelOptions(provider, customModels, selectedModel);
+  const trimmedSelectedModel = selectedModel?.trim();
+  if (trimmedSelectedModel) {
+    const direct = options.find((option) => option.slug === trimmedSelectedModel);
+    if (direct) {
+      return direct.slug;
+    }
+
+    const byName = options.find(
+      (option) => option.name.toLowerCase() === trimmedSelectedModel.toLowerCase(),
+    );
+    if (byName) {
+      return byName.slug;
+    }
+  }
+
+  const normalizedSelectedModel = normalizeModelSlug(selectedModel, provider);
+  if (!normalizedSelectedModel) {
+    return getDefaultModel(provider);
+  }
+
+  return (
+    options.find((option) => option.slug === normalizedSelectedModel)?.slug ??
+    getDefaultModel(provider)
+  );
+}
+
 export function getSlashModelOptions(
   provider: ProviderKind,
   customModels: readonly string[],
diff --git a/apps/web/src/components/ChatView.tsx b/apps/web/src/components/ChatView.tsx
index 7c346c726c29dbb139c6cabd616b75a42f65520b..94d10ee5bc2ce3c2ced1cb6bc2d4fbe9197ca763 100644
--- a/apps/web/src/components/ChatView.tsx
+++ b/apps/web/src/components/ChatView.tsx
@@ -196,7 +196,7 @@ import { Toggle } from "./ui/toggle";
 import { SidebarTrigger } from "./ui/sidebar";
 import { newCommandId, newMessageId, newThreadId } from "~/lib/utils";
 import { readNativeApi } from "~/nativeApi";
-import { getAppModelOptions, useAppSettings } from "../appSettings";
+import { getAppModelOptions, resolveAppModelSelection, useAppSettings } from "../appSettings";
 import {
   type ComposerImageAttachment,
   type DraftThreadEnvMode,
@@ -762,30 +762,18 @@ export default function ChatView({ threadId }: ChatViewProps) {
     selectedProvider,
     activeThread?.model ?? activeProject?.model ?? getDefaultModel(selectedProvider),
   );
+  const customModelsForSelectedProvider = settings.customCodexModels;
   const selectedModel = useMemo(() => {
     const draftModel = composerDraft.model;
     if (!draftModel) {
       return baseThreadModel;
     }
-
-    const providerOptions = getCustomModelOptionsByProvider(settings)[selectedProvider];
-    const directMatch = providerOptions.find((option) => option.slug === draftModel);
-    if (directMatch) {
-      return directMatch.slug as ModelSlug;
-    }
-
-    const normalizedDraftModel = normalizeModelSlug(draftModel, selectedProvider);
-    if (normalizedDraftModel) {
-      const normalizedMatch = providerOptions.find(
-        (option) => option.slug === normalizedDraftModel,
-      );
-      if (normalizedMatch) {
-        return normalizedMatch.slug as ModelSlug;
-      }
-    }
-
-    return resolveModelSlugForProvider(selectedProvider, draftModel);
-  }, [baseThreadModel, composerDraft.model, selectedProvider, settings]);
+    return resolveAppModelSelection(
+      selectedProvider,
+      customModelsForSelectedProvider,
+      draftModel,
+    ) as ModelSlug;
+  }, [baseThreadModel, composerDraft.model, customModelsForSelectedProvider, selectedProvider]);
   const reasoningOptions = getReasoningEffortOptions(selectedProvider);
   const supportsReasoningEffort = reasoningOptions.length > 0;
   const selectedEffort = composerDraft.effort ?? getDefaultReasoningEffort(selectedProvider);
@@ -2979,9 +2967,11 @@ export default function ChatView({ threadId }: ChatViewProps) {
         scheduleComposerFocus();
         return;
       }
-      const resolvedModel = resolveModelSlugForProvider(provider, model);
       setComposerDraftProvider(activeThread.id, provider);
-      setComposerDraftModel(activeThread.id, resolvedModel);
+      setComposerDraftModel(
+        activeThread.id,
+        resolveAppModelSelection(provider, settings.customCodexModels, model),
+      );
       scheduleComposerFocus();
     },
     [
@@ -2990,6 +2980,7 @@ export default function ChatView({ threadId }: ChatViewProps) {
       scheduleComposerFocus,
       setComposerDraftModel,
       setComposerDraftProvider,
+      settings.customCodexModels,
     ],
   );
   const onEffortSelect = useCallback(