fix(onboard): align xAI default model to grok-4

src/commands/auth-choice.apply.xai.ts

@@ -36,7 +36,7 @@ export async function applyAuthChoiceXAI(
   let hasCredential = false;
   const optsKey = params.opts?.xaiApiKey?.trim();
   if (optsKey) {
-    await setXaiApiKey(normalizeApiKeyInput(optsKey), params.agentDir);
+    setXaiApiKey(normalizeApiKeyInput(optsKey), params.agentDir);
     hasCredential = true;
   }
 
@@ -48,7 +48,7 @@ export async function applyAuthChoiceXAI(
         initialValue: true,
       });
       if (useExisting) {
-        await setXaiApiKey(envKey.apiKey, params.agentDir);
+        setXaiApiKey(envKey.apiKey, params.agentDir);
         hasCredential = true;
       }
     }
@@ -59,7 +59,7 @@ export async function applyAuthChoiceXAI(
       message: "Enter xAI API key",
       validate: validateApiKeyInput,
     });
-    await setXaiApiKey(normalizeApiKeyInput(String(key)), params.agentDir);
+    setXaiApiKey(normalizeApiKeyInput(String(key)), params.agentDir);
   }
 
   nextConfig = applyAuthProfileConfig(nextConfig, {

src/commands/auth-choice.test.ts

@@ -237,7 +237,7 @@ describe("applyAuthChoice", () => {
       mode: "api_key",
     });
     expect(result.config.agents?.defaults?.model?.primary).toBe("openai/gpt-4o-mini");
-    expect(result.agentModelOverride).toBe("xai/grok-2-latest");
+    expect(result.agentModelOverride).toBe("xai/grok-4");
 
     const authProfilePath = authProfilePathFor(requireAgentDir());
     const raw = await fs.readFile(authProfilePath, "utf8");

src/commands/onboard-auth.credentials.ts

@@ -205,7 +205,7 @@ export async function setOpencodeZenApiKey(key: string, agentDir?: string) {
   });
 }
 
-export async function setXaiApiKey(key: string, agentDir?: string) {
+export function setXaiApiKey(key: string, agentDir?: string) {
   upsertAuthProfile({
     profileId: "xai:default",
     credential: {

src/commands/onboard-auth.models.ts

@@ -94,7 +94,7 @@ export function buildMoonshotModelDefinition(): ModelDefinitionConfig {
 }
 
 export const XAI_BASE_URL = "https://api.x.ai/v1";
-export const XAI_DEFAULT_MODEL_ID = "grok-2-latest";
+export const XAI_DEFAULT_MODEL_ID = "grok-4";
 export const XAI_DEFAULT_MODEL_REF = `xai/${XAI_DEFAULT_MODEL_ID}`;
 export const XAI_DEFAULT_CONTEXT_WINDOW = 131072;
 export const XAI_DEFAULT_MAX_TOKENS = 8192;
@@ -108,7 +108,7 @@ export const XAI_DEFAULT_COST = {
 export function buildXaiModelDefinition(): ModelDefinitionConfig {
   return {
     id: XAI_DEFAULT_MODEL_ID,
-    name: "Grok 2",
+    name: "Grok 4",
     reasoning: false,
     input: ["text"],
     cost: XAI_DEFAULT_COST,

src/commands/onboard-auth.test.ts

@@ -13,11 +13,14 @@ import {
   applyOpenrouterProviderConfig,
   applySyntheticConfig,
   applySyntheticProviderConfig,
+  applyXaiConfig,
+  applyXaiProviderConfig,
   applyXiaomiConfig,
   applyXiaomiProviderConfig,
   OPENROUTER_DEFAULT_MODEL_REF,
   SYNTHETIC_DEFAULT_MODEL_ID,
   SYNTHETIC_DEFAULT_MODEL_REF,
+  XAI_DEFAULT_MODEL_REF,
   setMinimaxApiKey,
   writeOAuthCredentials,
 } from "./onboard-auth.js";
@@ -389,6 +392,65 @@ describe("applyXiaomiConfig", () => {
   });
 });
 
+describe("applyXaiConfig", () => {
+  it("adds xAI provider with correct settings", () => {
+    const cfg = applyXaiConfig({});
+    expect(cfg.models?.providers?.xai).toMatchObject({
+      baseUrl: "https://api.x.ai/v1",
+      api: "openai-completions",
+    });
+    expect(cfg.agents?.defaults?.model?.primary).toBe(XAI_DEFAULT_MODEL_REF);
+  });
+
+  it("preserves existing model fallbacks", () => {
+    const cfg = applyXaiConfig({
+      agents: {
+        defaults: {
+          model: { fallbacks: ["anthropic/claude-opus-4-5"] },
+        },
+      },
+    });
+    expect(cfg.agents?.defaults?.model?.fallbacks).toEqual(["anthropic/claude-opus-4-5"]);
+  });
+});
+
+describe("applyXaiProviderConfig", () => {
+  it("adds model alias", () => {
+    const cfg = applyXaiProviderConfig({});
+    expect(cfg.agents?.defaults?.models?.[XAI_DEFAULT_MODEL_REF]?.alias).toBe("Grok");
+  });
+
+  it("merges xAI models and keeps existing provider overrides", () => {
+    const cfg = applyXaiProviderConfig({
+      models: {
+        providers: {
+          xai: {
+            baseUrl: "https://old.example.com",
+            apiKey: "old-key",
+            api: "anthropic-messages",
+            models: [
+              {
+                id: "custom-model",
+                name: "Custom",
+                reasoning: false,
+                input: ["text"],
+                cost: { input: 1, output: 2, cacheRead: 0, cacheWrite: 0 },
+                contextWindow: 1000,
+                maxTokens: 100,
+              },
+            ],
+          },
+        },
+      },
+    });
+
+    expect(cfg.models?.providers?.xai?.baseUrl).toBe("https://api.x.ai/v1");
+    expect(cfg.models?.providers?.xai?.api).toBe("openai-completions");
+    expect(cfg.models?.providers?.xai?.apiKey).toBe("old-key");
+    expect(cfg.models?.providers?.xai?.models.map((m) => m.id)).toEqual(["custom-model", "grok-4"]);
+  });
+});
+
 describe("applyOpencodeZenProviderConfig", () => {
   it("adds allowlist entry for the default model", () => {
     const cfg = applyOpencodeZenProviderConfig({});

src/commands/onboard-non-interactive.xai.test.ts

@@ -65,7 +65,7 @@ describe("onboard (non-interactive): xAI", () => {
 
       expect(cfg.auth?.profiles?.["xai:default"]?.provider).toBe("xai");
       expect(cfg.auth?.profiles?.["xai:default"]?.mode).toBe("api_key");
-      expect(cfg.agents?.defaults?.model?.primary).toBe("xai/grok-2-latest");
+      expect(cfg.agents?.defaults?.model?.primary).toBe("xai/grok-4");
 
       const { ensureAuthProfileStore } = await import("../agents/auth-profiles.js");
       const store = ensureAuthProfileStore();

src/commands/onboard-non-interactive/local/auth-choice.ts

@@ -233,7 +233,7 @@ export async function applyNonInteractiveAuthChoice(params: {
       return null;
     }
     if (resolved.source !== "profile") {
-      await setXaiApiKey(resolved.key);
+      setXaiApiKey(resolved.key);
     }
     nextConfig = applyAuthProfileConfig(nextConfig, {
       profileId: "xai:default",