diff --git a/changelog.d/features/13318-gemini-3.8-flash.md b/changelog.d/features/13318-gemini-3.8-flash.md
new file mode 100644
index 0000000000..8a0d95531a
--- /dev/null
+++ b/changelog.d/features/13318-gemini-3.8-flash.md
@@ -0,0 +1 @@
+- **feat(models):** add Gemini 3.8 Flash tiers to Antigravity and AGY catalogs ([#13318](https://github.com/diegosouzapw/OmniRoute/pull/13318)) — thanks @tuandinh0801, with credit to #12499 (@Abhishekchhetri020)
diff --git a/open-sse/services/antigravityVersion.ts b/open-sse/services/antigravityVersion.ts
index 6a8e5c7cc8..7914674109 100644
--- a/open-sse/services/antigravityVersion.ts
+++ b/open-sse/services/antigravityVersion.ts
@@ -5,8 +5,8 @@ const ANTIGRAVITY_CLI_RELEASE_URL =
 
 export const ANTIGRAVITY_VERSION_CACHE_TTL_MS = 6 * 60 * 60 * 1000;
 export const ANTIGRAVITY_VERSION_FETCH_TIMEOUT_MS = 5_000;
-export const ANTIGRAVITY_IDE_FALLBACK_VERSION = "2.1.1";
-export const ANTIGRAVITY_CLI_FALLBACK_VERSION = "1.1.5";
+export const ANTIGRAVITY_IDE_FALLBACK_VERSION = "2.5.5";
+export const ANTIGRAVITY_CLI_FALLBACK_VERSION = "1.1.24";
 
 type VersionCache = {
   fetchedAt: number;
diff --git a/src/shared/constants/cliTools.ts b/src/shared/constants/cliTools.ts
index 01401ea986..87ea13ce2c 100644
--- a/src/shared/constants/cliTools.ts
+++ b/src/shared/constants/cliTools.ts
@@ -242,6 +242,9 @@ export const CLI_TOOLS: Record<string, CliCatalogEntry> = {
     acpSpawnable: false,
     baseUrlSupport: "none",
     modelAliases: [
+      "gemini-3.8-flash-high",
+      "gemini-3.8-flash-medium",
+      "gemini-3.8-flash-low",
       "gemini-3.7-flash-high",
       "gemini-3.7-flash-medium",
       "gemini-3.7-flash-low",
@@ -252,6 +255,9 @@ export const CLI_TOOLS: Record<string, CliCatalogEntry> = {
       "gpt-oss-120b-medium",
     ],
     defaultModels: [
+      createCliModel("gemini-3.8-flash-high", "Gemini 3.8 Flash High"),
+      createCliModel("gemini-3.8-flash-medium", "Gemini 3.8 Flash Medium"),
+      createCliModel("gemini-3.8-flash-low", "Gemini 3.8 Flash Low"),
       createCliModel("gemini-3.7-flash-high", "Gemini 3.7 Flash High"),
       createCliModel("gemini-3.7-flash-medium", "Gemini 3.7 Flash Medium"),
       createCliModel("gemini-3.7-flash-low", "Gemini 3.7 Flash Low"),
diff --git a/src/shared/constants/pricing/oauth-subscriptions.ts b/src/shared/constants/pricing/oauth-subscriptions.ts
index a6e68896ba..678ec95dc9 100644
--- a/src/shared/constants/pricing/oauth-subscriptions.ts
+++ b/src/shared/constants/pricing/oauth-subscriptions.ts
@@ -15,6 +15,9 @@ import {
 } from "./shared-tiers";
 
 const ANTIGRAVITY_GEMINI_3_7_PRICING = {
+  "gemini-3.8-flash-low": GEMINI_3_7_FLASH_PROMO_PRICING,
+  "gemini-3.8-flash-medium": GEMINI_3_7_FLASH_PROMO_PRICING,
+  "gemini-3.8-flash-high": GEMINI_3_7_FLASH_PROMO_PRICING,
   "gemini-3.7-flash-low": GEMINI_3_7_FLASH_PROMO_PRICING,
   "gemini-3.7-flash-medium": GEMINI_3_7_FLASH_PROMO_PRICING,
   "gemini-3.7-flash-high": GEMINI_3_7_FLASH_PROMO_PRICING,
diff --git a/tests/unit/antigravity-version.test.ts b/tests/unit/antigravity-version.test.ts
index cf94ab6adf..174f947157 100644
--- a/tests/unit/antigravity-version.test.ts
+++ b/tests/unit/antigravity-version.test.ts
@@ -24,29 +24,29 @@ test.afterEach(() => {
 test("IDE and CLI start with independent captured fallback versions", () => {
   assert.equal(getCachedAntigravityIdeVersion(), ANTIGRAVITY_IDE_FALLBACK_VERSION);
   assert.equal(getCachedAntigravityCliVersion(), ANTIGRAVITY_CLI_FALLBACK_VERSION);
-  assert.equal(ANTIGRAVITY_IDE_FALLBACK_VERSION, "2.1.1");
-  assert.equal(ANTIGRAVITY_CLI_FALLBACK_VERSION, "1.1.5");
+  assert.equal(ANTIGRAVITY_IDE_FALLBACK_VERSION, "2.5.5");
+  assert.equal(ANTIGRAVITY_CLI_FALLBACK_VERSION, "1.1.24");
 });
 
 test("IDE resolver reads the official updater feed and caches only the IDE version", async () => {
   const urls: string[] = [];
   const fetchMock = async (url: string | URL | Request) => {
     urls.push(String(url));
-    return new Response(JSON.stringify([{ version: "2.2.0", execution_id: "ide-release" }]), {
+    return new Response(JSON.stringify([{ version: "2.6.0", execution_id: "ide-release" }]), {
       status: 200,
       headers: { "Content-Type": "application/json" },
     });
   };
 
-  assert.equal(await resolveAntigravityIdeVersion(fetchMock as typeof fetch), "2.2.0");
-  assert.equal(await resolveAntigravityIdeVersion(fetchMock as typeof fetch), "2.2.0");
+  assert.equal(await resolveAntigravityIdeVersion(fetchMock as typeof fetch), "2.6.0");
+  assert.equal(await resolveAntigravityIdeVersion(fetchMock as typeof fetch), "2.6.0");
   assert.equal(urls.length, 1);
   assert.equal(
     urls[0],
     "https://antigravity-auto-updater-974169037036.us-central1.run.app/releases"
   );
-  assert.equal(getCachedAntigravityIdeVersion(), "2.2.0");
-  assert.equal(getCachedAntigravityCliVersion(), "1.1.5");
+  assert.equal(getCachedAntigravityIdeVersion(), "2.6.0");
+  assert.equal(getCachedAntigravityCliVersion(), ANTIGRAVITY_CLI_FALLBACK_VERSION);
 });
 
 test("IDE resolver selects the newest feed entry and never falls below its version floor", async () => {
@@ -54,14 +54,14 @@ test("IDE resolver selects the newest feed entry and never falls below its versi
     new Response(
       JSON.stringify([
         { version: "2.0.0" },
-        { version: "2.4.0" },
-        { version: "2.2.0" },
+        { version: "2.6.0" },
+        { version: "2.6.0" },
         { version: "invalid" },
       ]),
       { status: 200, headers: { "Content-Type": "application/json" } }
     );
 
-  assert.equal(await resolveAntigravityIdeVersion(mixedFeedFetch as typeof fetch), "2.4.0");
+  assert.equal(await resolveAntigravityIdeVersion(mixedFeedFetch as typeof fetch), "2.6.0");
 
   clearAntigravityVersionCaches();
   const staleFeedFetch = async () =>
@@ -80,7 +80,7 @@ test("IDE resolver selects the newest feed entry and never falls below its versi
 test("IDE resolver keeps a newer cached version when a later feed response is older", async () => {
   let now = 1_000;
   Date.now = () => now;
-  seedAntigravityIdeVersionCache("2.5.0", now);
+  seedAntigravityIdeVersionCache("2.6.0", now);
   now += ANTIGRAVITY_VERSION_CACHE_TTL_MS + 1;
 
   const olderFeedFetch = async () =>
@@ -89,8 +89,8 @@ test("IDE resolver keeps a newer cached version when a later feed response is ol
       headers: { "Content-Type": "application/json" },
     });
 
-  assert.equal(await resolveAntigravityIdeVersion(olderFeedFetch as typeof fetch), "2.5.0");
-  assert.equal(getCachedAntigravityIdeVersion(), "2.5.0");
+  assert.equal(await resolveAntigravityIdeVersion(olderFeedFetch as typeof fetch), "2.6.0");
+  assert.equal(getCachedAntigravityIdeVersion(), "2.6.0");
 });
 
 test("CLI resolver reads the official Google GitHub release and caches only the CLI version", async () => {
@@ -111,7 +111,7 @@ test("CLI resolver reads the official Google GitHub release and caches only the
     "https://api.github.com/repos/google-antigravity/antigravity-cli/releases/latest"
   );
   assert.equal(getCachedAntigravityCliVersion(), "1.2.0");
-  assert.equal(getCachedAntigravityIdeVersion(), "2.1.1");
+  assert.equal(getCachedAntigravityIdeVersion(), ANTIGRAVITY_IDE_FALLBACK_VERSION);
 });
 
 test("IDE and CLI TTL refreshes are independent", async () => {
@@ -120,19 +120,19 @@ test("IDE and CLI TTL refreshes are independent", async () => {
   seedAntigravityCliVersionCache("1.1.5", now);
 
   const firstFetch = async () =>
-    new Response(JSON.stringify([{ version: "2.2.0" }]), {
+    new Response(JSON.stringify([{ version: "2.6.0" }]), {
       status: 200,
       headers: { "Content-Type": "application/json" },
     });
   const secondFetch = async () =>
-    new Response(JSON.stringify([{ version: "2.3.0" }]), {
+    new Response(JSON.stringify([{ version: "2.7.0" }]), {
       status: 200,
       headers: { "Content-Type": "application/json" },
     });
 
-  assert.equal(await resolveAntigravityIdeVersion(firstFetch as typeof fetch), "2.2.0");
+  assert.equal(await resolveAntigravityIdeVersion(firstFetch as typeof fetch), "2.6.0");
   now += ANTIGRAVITY_VERSION_CACHE_TTL_MS + 1;
-  assert.equal(await resolveAntigravityIdeVersion(secondFetch as typeof fetch), "2.3.0");
+  assert.equal(await resolveAntigravityIdeVersion(secondFetch as typeof fetch), "2.7.0");
   assert.equal(getCachedAntigravityCliVersion(), "1.1.5");
 });
 
@@ -150,9 +150,9 @@ test("each resolver falls back only to its own last known good version", async (
     ANTIGRAVITY_CLI_FALLBACK_VERSION
   );
 
-  seedAntigravityIdeVersionCache("2.4.0", 0);
+  seedAntigravityIdeVersionCache("2.6.0", 0);
   seedAntigravityCliVersionCache("1.3.0", 0);
-  assert.equal(await resolveAntigravityIdeVersion(failingFetch as typeof fetch), "2.4.0");
+  assert.equal(await resolveAntigravityIdeVersion(failingFetch as typeof fetch), "2.6.0");
   assert.equal(await resolveAntigravityCliVersion(failingFetch as typeof fetch), "1.3.0");
 });
 
@@ -171,7 +171,7 @@ test("concurrent requests coalesce within each product without crossing products
   const ideFetch = async () => {
     ideCalls += 1;
     await ideGate;
-    return new Response(JSON.stringify([{ version: "2.5.0" }]), { status: 200 });
+    return new Response(JSON.stringify([{ version: "2.6.0" }]), { status: 200 });
   };
   const cliFetch = async () => {
     cliCalls += 1;
@@ -186,7 +186,7 @@ test("concurrent requests coalesce within each product without crossing products
   releaseIde?.();
   releaseCli?.();
 
-  assert.deepEqual(await Promise.all([ideOne, ideTwo]), ["2.5.0", "2.5.0"]);
+  assert.deepEqual(await Promise.all([ideOne, ideTwo]), ["2.6.0", "2.6.0"]);
   assert.deepEqual(await Promise.all([cliOne, cliTwo]), ["1.4.0", "1.4.0"]);
   assert.equal(ideCalls, 1);
   assert.equal(cliCalls, 1);