diff --git a/src/agents/models-config.providers.ts b/src/agents/models-config.providers.ts
index 0cd034c82..fee1ad4e3 100644
--- a/src/agents/models-config.providers.ts
+++ b/src/agents/models-config.providers.ts
@@ -13,6 +13,7 @@ import {
   SYNTHETIC_MODEL_CATALOG,
 } from "./synthetic-models.js";
 import { discoverVeniceModels, VENICE_BASE_URL } from "./venice-models.js";
+import { discoverXaiModels, XAI_BASE_URL } from "./xai-models.js";
 
 type ModelsConfig = NonNullable<OpenClawConfig["models"]>;
 export type ProviderConfig = NonNullable<ModelsConfig["providers"]>[string];
@@ -379,6 +380,15 @@ async function buildVeniceProvider(): Promise<ProviderConfig> {
   };
 }
 
+async function buildXaiProvider(apiKey: string): Promise<ProviderConfig> {
+  const models = await discoverXaiModels(apiKey);
+  return {
+    baseUrl: XAI_BASE_URL,
+    api: "openai-completions",
+    models,
+  };
+}
+
 async function buildOllamaProvider(): Promise<ProviderConfig> {
   const models = await discoverOllamaModels();
   return {
@@ -431,6 +441,13 @@ export async function resolveImplicitProviders(params: {
     providers.venice = { ...(await buildVeniceProvider()), apiKey: veniceKey };
   }
 
+  const xaiKey =
+    resolveEnvApiKeyVarName("xai") ??
+    resolveApiKeyFromProfiles({ provider: "xai", store: authStore });
+  if (xaiKey) {
+    providers.xai = { ...(await buildXaiProvider(xaiKey)), apiKey: xaiKey };
+  }
+
   const qwenProfiles = listProfilesForProvider(authStore, "qwen-portal");
   if (qwenProfiles.length > 0) {
     providers["qwen-portal"] = {
diff --git a/src/agents/xai-models.test.ts b/src/agents/xai-models.test.ts
new file mode 100644
index 000000000..acc966407
--- /dev/null
+++ b/src/agents/xai-models.test.ts
@@ -0,0 +1,135 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  buildXaiModelDefinition,
+  discoverXaiModels,
+  XAI_BASE_URL,
+  XAI_DEFAULT_COST,
+  XAI_DEFAULT_MODEL_ID,
+  XAI_MODEL_CATALOG,
+} from "./xai-models.js";
+
+describe("XAI_MODEL_CATALOG", () => {
+  it("contains expected model series", () => {
+    const ids = XAI_MODEL_CATALOG.map((m) => m.id);
+
+    // Grok 4.1 series
+    expect(ids).toContain("grok-4-1-fast-reasoning");
+    expect(ids).toContain("grok-4-1-fast-non-reasoning");
+
+    // Grok 4 series
+    expect(ids).toContain("grok-4-07-09");
+    expect(ids).toContain("grok-4-fast-reasoning");
+    expect(ids).toContain("grok-4-fast-non-reasoning");
+
+    // Grok 3 series
+    expect(ids).toContain("grok-3-beta");
+    expect(ids).toContain("grok-3-mini-beta");
+
+    // Grok 2 series
+    expect(ids).toContain("grok-2-1212");
+    expect(ids).toContain("grok-2-vision-1212");
+
+    // Specialized
+    expect(ids).toContain("grok-code-fast-1");
+  });
+
+  it("marks reasoning models correctly", () => {
+    const reasoningModels = XAI_MODEL_CATALOG.filter((m) => m.reasoning);
+    const reasoningIds = reasoningModels.map((m) => m.id);
+
+    expect(reasoningIds).toContain("grok-4-1-fast-reasoning");
+    expect(reasoningIds).toContain("grok-4-fast-reasoning");
+    expect(reasoningIds).toContain("grok-code-fast-1");
+
+    // Non-reasoning models should not be in this list
+    expect(reasoningIds).not.toContain("grok-4-1-fast-non-reasoning");
+    expect(reasoningIds).not.toContain("grok-3-beta");
+  });
+
+  it("marks vision models with image input", () => {
+    const visionModels = XAI_MODEL_CATALOG.filter((m) => m.input.includes("image"));
+    const visionIds = visionModels.map((m) => m.id);
+
+    expect(visionIds).toContain("grok-4-1-fast-reasoning");
+    expect(visionIds).toContain("grok-4-1-fast-non-reasoning");
+    expect(visionIds).toContain("grok-2-vision-1212");
+
+    // Text-only models should not have image input
+    expect(visionIds).not.toContain("grok-3-beta");
+    expect(visionIds).not.toContain("grok-4-07-09");
+  });
+});
+
+describe("buildXaiModelDefinition", () => {
+  it("builds a valid ModelDefinitionConfig from catalog entry", () => {
+    const entry = XAI_MODEL_CATALOG.find((m) => m.id === "grok-3-beta")!;
+    const config = buildXaiModelDefinition(entry);
+
+    expect(config.id).toBe("grok-3-beta");
+    expect(config.name).toBe("Grok 3");
+    expect(config.reasoning).toBe(false);
+    expect(config.input).toEqual(["text"]);
+    expect(config.cost).toEqual(XAI_DEFAULT_COST);
+    expect(config.contextWindow).toBe(131072);
+    expect(config.maxTokens).toBe(8192);
+  });
+
+  it("preserves vision input for vision models", () => {
+    const entry = XAI_MODEL_CATALOG.find((m) => m.id === "grok-2-vision-1212")!;
+    const config = buildXaiModelDefinition(entry);
+
+    expect(config.input).toEqual(["text", "image"]);
+  });
+
+  it("preserves reasoning flag for reasoning models", () => {
+    const entry = XAI_MODEL_CATALOG.find((m) => m.id === "grok-4-fast-reasoning")!;
+    const config = buildXaiModelDefinition(entry);
+
+    expect(config.reasoning).toBe(true);
+  });
+});
+
+describe("discoverXaiModels", () => {
+  it("returns static catalog in test environment", async () => {
+    // The function checks for test environment and returns static catalog
+    const models = await discoverXaiModels("test-api-key");
+
+    expect(models.length).toBe(XAI_MODEL_CATALOG.length);
+    expect(models.map((m) => m.id)).toContain("grok-3-beta");
+    expect(models.map((m) => m.id)).toContain("grok-4-1-fast-reasoning");
+  });
+
+  it("returns valid ModelDefinitionConfig objects", async () => {
+    const models = await discoverXaiModels("test-api-key");
+
+    for (const model of models) {
+      expect(model.id).toBeDefined();
+      expect(model.name).toBeDefined();
+      expect(typeof model.reasoning).toBe("boolean");
+      expect(Array.isArray(model.input)).toBe(true);
+      expect(model.cost).toBeDefined();
+      expect(typeof model.contextWindow).toBe("number");
+      expect(typeof model.maxTokens).toBe("number");
+    }
+  });
+});
+
+describe("XAI constants", () => {
+  it("has correct base URL", () => {
+    expect(XAI_BASE_URL).toBe("https://api.x.ai/v1");
+  });
+
+  it("has correct default model ID", () => {
+    expect(XAI_DEFAULT_MODEL_ID).toBe("grok-3-beta");
+  });
+
+  it("has zero costs (credit-based)", () => {
+    expect(XAI_DEFAULT_COST).toEqual({
+      input: 0,
+      output: 0,
+      cacheRead: 0,
+      cacheWrite: 0,
+    });
+  });
+});
diff --git a/src/agents/xai-models.ts b/src/agents/xai-models.ts
new file mode 100644
index 000000000..df3dba9fe
--- /dev/null
+++ b/src/agents/xai-models.ts
@@ -0,0 +1,213 @@
+import type { ModelDefinitionConfig } from "../config/types.js";
+
+export const XAI_BASE_URL = "https://api.x.ai/v1";
+export const XAI_DEFAULT_MODEL_ID = "grok-3-beta";
+export const XAI_DEFAULT_MODEL_REF = `xai/${XAI_DEFAULT_MODEL_ID}`;
+
+// xAI pricing varies by model; set to 0 as placeholder
+export const XAI_DEFAULT_COST = {
+  input: 0,
+  output: 0,
+  cacheRead: 0,
+  cacheWrite: 0,
+};
+
+/**
+ * Complete catalog of xAI (Grok) models.
+ *
+ * This catalog serves as a fallback when the xAI API is unreachable
+ * or when no API key is configured. xAI's /v1/models endpoint requires
+ * authentication, unlike some other providers.
+ *
+ * Models organized by series, newest first.
+ */
+export const XAI_MODEL_CATALOG = [
+  // Grok 4.1 Series (latest)
+  {
+    id: "grok-4-1-fast-reasoning",
+    name: "Grok 4.1 Fast Reasoning",
+    reasoning: true,
+    input: ["text", "image"] as const,
+    contextWindow: 2000000,
+    maxTokens: 16384,
+  },
+  {
+    id: "grok-4-1-fast-non-reasoning",
+    name: "Grok 4.1 Fast",
+    reasoning: false,
+    input: ["text", "image"] as const,
+    contextWindow: 2000000,
+    maxTokens: 16384,
+  },
+
+  // Grok 4 Series
+  {
+    id: "grok-4-07-09",
+    name: "Grok 4",
+    reasoning: false,
+    input: ["text"] as const,
+    contextWindow: 256000,
+    maxTokens: 16384,
+  },
+  {
+    id: "grok-4-fast-reasoning",
+    name: "Grok 4 Fast Reasoning",
+    reasoning: true,
+    input: ["text"] as const,
+    contextWindow: 2000000,
+    maxTokens: 16384,
+  },
+  {
+    id: "grok-4-fast-non-reasoning",
+    name: "Grok 4 Fast",
+    reasoning: false,
+    input: ["text"] as const,
+    contextWindow: 2000000,
+    maxTokens: 16384,
+  },
+
+  // Grok 3 Series
+  {
+    id: "grok-3-beta",
+    name: "Grok 3",
+    reasoning: false,
+    input: ["text"] as const,
+    contextWindow: 131072,
+    maxTokens: 8192,
+  },
+  {
+    id: "grok-3-mini-beta",
+    name: "Grok 3 Mini",
+    reasoning: false,
+    input: ["text"] as const,
+    contextWindow: 131072,
+    maxTokens: 8192,
+  },
+
+  // Grok 2 Series
+  {
+    id: "grok-2-1212",
+    name: "Grok 2",
+    reasoning: false,
+    input: ["text"] as const,
+    contextWindow: 32768,
+    maxTokens: 8192,
+  },
+  {
+    id: "grok-2-vision-1212",
+    name: "Grok 2 Vision",
+    reasoning: false,
+    input: ["text", "image"] as const,
+    contextWindow: 32768,
+    maxTokens: 8192,
+  },
+
+  // Specialized
+  {
+    id: "grok-code-fast-1",
+    name: "Grok Code Fast 1",
+    reasoning: true,
+    input: ["text"] as const,
+    contextWindow: 256000,
+    maxTokens: 16384,
+  },
+] as const;
+
+export type XaiCatalogEntry = (typeof XAI_MODEL_CATALOG)[number];
+
+/**
+ * Build a ModelDefinitionConfig from an xAI catalog entry.
+ */
+export function buildXaiModelDefinition(entry: XaiCatalogEntry): ModelDefinitionConfig {
+  return {
+    id: entry.id,
+    name: entry.name,
+    reasoning: entry.reasoning,
+    input: [...entry.input],
+    cost: XAI_DEFAULT_COST,
+    contextWindow: entry.contextWindow,
+    maxTokens: entry.maxTokens,
+  };
+}
+
+// xAI API response types (OpenAI-compatible format)
+interface XaiModel {
+  id: string;
+  object: "model";
+  created: number;
+  owned_by: string;
+}
+
+interface XaiModelsResponse {
+  object: "list";
+  data: XaiModel[];
+}
+
+/**
+ * Discover models from xAI API with fallback to static catalog.
+ *
+ * Unlike Venice, xAI's /v1/models endpoint requires authentication,
+ * so discovery only works when an API key is provided.
+ */
+export async function discoverXaiModels(apiKey: string): Promise<ModelDefinitionConfig[]> {
+  // Skip API discovery in test environment
+  if (process.env.NODE_ENV === "test" || process.env.VITEST) {
+    return XAI_MODEL_CATALOG.map(buildXaiModelDefinition);
+  }
+
+  try {
+    const response = await fetch(`${XAI_BASE_URL}/models`, {
+      headers: {
+        Authorization: `Bearer ${apiKey}`,
+      },
+      signal: AbortSignal.timeout(5000),
+    });
+
+    if (!response.ok) {
+      console.warn(
+        `[xai-models] Failed to discover models: HTTP ${response.status}, using static catalog`,
+      );
+      return XAI_MODEL_CATALOG.map(buildXaiModelDefinition);
+    }
+
+    const data = (await response.json()) as XaiModelsResponse;
+    if (!Array.isArray(data.data) || data.data.length === 0) {
+      console.warn("[xai-models] No models found from API, using static catalog");
+      return XAI_MODEL_CATALOG.map(buildXaiModelDefinition);
+    }
+
+    // Merge discovered models with catalog metadata
+    const catalogById = new Map<string, XaiCatalogEntry>(XAI_MODEL_CATALOG.map((m) => [m.id, m]));
+    const models: ModelDefinitionConfig[] = [];
+
+    for (const apiModel of data.data) {
+      const catalogEntry = catalogById.get(apiModel.id);
+      if (catalogEntry) {
+        // Use catalog metadata for known models
+        models.push(buildXaiModelDefinition(catalogEntry));
+      } else {
+        // Create definition for newly discovered models not in catalog
+        const idLower = apiModel.id.toLowerCase();
+        const isReasoning =
+          idLower.includes("reasoning") || idLower.includes("think") || idLower.includes("r1");
+
+        const hasVision = idLower.includes("vision");
+
+        models.push({
+          id: apiModel.id,
+          name: apiModel.id, // xAI API only returns id, not display names
+          reasoning: isReasoning,
+          input: hasVision ? ["text", "image"] : ["text"],
+          cost: XAI_DEFAULT_COST,
+          contextWindow: 131072, // Conservative default
+          maxTokens: 8192,
+        });
+      }
+    }
+
+    return models.length > 0 ? models : XAI_MODEL_CATALOG.map(buildXaiModelDefinition);
+  } catch (error) {
+    console.warn(`[xai-models] Discovery failed: ${String(error)}, using static catalog`);
+    return XAI_MODEL_CATALOG.map(buildXaiModelDefinition);
+  }
+}