diff --git a/.changeset/fn-7714-grok-user-settings-apikey.md b/.changeset/fn-7714-grok-user-settings-apikey.md
new file mode 100644
index 0000000000..0955caf601
--- /dev/null
+++ b/.changeset/fn-7714-grok-user-settings-apikey.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Grok now uses the key from ~/.grok/user-settings.json when GROK_API_KEY is not set.
+category: fix
+dev: registerBuiltInGrokProvider (packages/core/src/grok-provider.ts) now hydrates process.env.GROK_API_KEY from ~/.grok/user-settings.json { apiKey } when the env var is unset/empty, so the provider's $GROK_API_KEY reference resolves. Env var always wins; missing/malformed/empty file is fail-soft (no throw, no env mutation). Mirrors the grok-runtime probe's fallback.
diff --git a/docs/settings-reference.md b/docs/settings-reference.md
index df498ca96f..072a06d621 100644
--- a/docs/settings-reference.md
+++ b/docs/settings-reference.md
@@ -966,7 +966,7 @@ Fusion resolves task models through workflow-backed lane values first, then glob
 
 Z.ai's built-in provider uses the existing `zai` auth entry / `ZAI_API_KEY` environment variable and includes `zai/glm-5.2` as a selectable model in the same dropdowns and workflow lane controls as the other built-in GLM models. If a pi extension also registers the `zai` provider, Fusion preserves the extension's models and re-adds any missing built-in Z.ai models so built-in GLM choices remain available.
 
-Grok (`grok-cli`) is likewise seeded as a built-in provider — xAI's OpenAI-compatible endpoint (`https://api.x.ai/v1`, api type `openai-completions`), API key `GROK_API_KEY` — into every model registry Fusion seeds (task execution, dashboard `/api/models`, and CLI `serve`/`daemon`/`dashboard`), mirroring the Z.ai pattern above. This makes `grok-cli/<model>` selections (e.g. `grok-cli/grok-4.5`) resolvable for execution even before the `grok` CLI binary is discovered or the picker surfaces additional Grok models (see the CLI-discovery paragraph below); a missing `GROK_API_KEY` surfaces only as a normal auth error at stream time, not a model-resolution failure.
+Grok (`grok-cli`) is likewise seeded as a built-in provider — xAI's OpenAI-compatible endpoint (`https://api.x.ai/v1`, api type `openai-completions`), API key `GROK_API_KEY` — into every model registry Fusion seeds (task execution, dashboard `/api/models`, and CLI `serve`/`daemon`/`dashboard`), mirroring the Z.ai pattern above. This makes `grok-cli/<model>` selections (e.g. `grok-cli/grok-4.5`) resolvable for execution even before the `grok` CLI binary is discovered or the picker surfaces additional Grok models (see the CLI-discovery paragraph below); a missing `GROK_API_KEY` surfaces only as a normal auth error at stream time, not a model-resolution failure. If `GROK_API_KEY` is not set in the environment, provider registration falls back to `~/.grok/user-settings.json`'s `apiKey` field (the same file the `grok` CLI itself writes on login) and hydrates `process.env.GROK_API_KEY` from it, so an operator who authenticated via the `grok` CLI but never exported the env var still resolves a key; an already-set env var always wins, and a missing/malformed/empty settings file is fail-soft (no error, no env mutation).
 
 When the Hermes Runtime plugin (`fusion-plugin-hermes-runtime`) is installed and the local `hermes` CLI has configured profiles (`hermes profile list`), those profiles are surfaced additively in `/api/models` under the `hermes` provider — one row per profile, id/name derived from the profile name and its configured model. This surfacing is read-only (Fusion does not create or edit Hermes profiles) and is fetched through a short-TTL, single-flight cache so the model picker never spawns the `hermes` CLI on every request; a missing/failed `hermes` binary simply yields zero Hermes rows without affecting other providers.
 
diff --git a/packages/core/src/__tests__/grok-provider-user-settings.test.ts b/packages/core/src/__tests__/grok-provider-user-settings.test.ts
new file mode 100644
index 0000000000..fe27eca3ed
--- /dev/null
+++ b/packages/core/src/__tests__/grok-provider-user-settings.test.ts
@@ -0,0 +1,156 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("node:fs", () => ({ readFileSync: vi.fn() }));
+
+import { readFileSync } from "node:fs";
+import {
+  GROK_CLI_PROVIDER_ID,
+  GROK_PROVIDER_REGISTRATION,
+  hydrateGrokApiKeyFromUserSettings,
+  registerBuiltInGrokProvider,
+} from "../grok-provider.js";
+
+const ORIGINAL_ENV = { ...process.env };
+
+function makeFakeRegistry() {
+  const registeredProviders = new Map<string, unknown>();
+  return {
+    registeredProviders,
+    registerProvider(providerName: string, config: unknown) {
+      registeredProviders.set(providerName, config);
+    },
+  };
+}
+
+/*
+FNXC:ProviderAuth 2026-07-09-00:00:
+FN-7714 regression coverage for hydrateGrokApiKeyFromUserSettings / registerBuiltInGrokProvider:
+mirrors probe.test.ts's fallback/precedence/fail-soft matrix so the $GROK_API_KEY env
+reference resolves from ~/.grok/user-settings.json when the env var is unset, without ever
+overwriting an operator-provided env value or throwing on a missing/malformed file.
+*/
+describe("hydrateGrokApiKeyFromUserSettings", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    process.env = { ...ORIGINAL_ENV };
+    delete process.env.GROK_API_KEY;
+  });
+
+  it("reproduces then resolves the original unresolved-key symptom: env unset + file has apiKey", () => {
+    // Original symptom: GROK_API_KEY unset means $GROK_API_KEY resolves to nothing.
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "xai-from-file" }));
+
+    hydrateGrokApiKeyFromUserSettings();
+
+    // Assertion it is gone: process.env.GROK_API_KEY is now populated so $GROK_API_KEY resolves.
+    expect(process.env.GROK_API_KEY).toBe("xai-from-file");
+  });
+
+  it("env set (non-empty) always wins and the file is never read", () => {
+    process.env.GROK_API_KEY = "xai-from-env";
+    hydrateGrokApiKeyFromUserSettings();
+
+    expect(process.env.GROK_API_KEY).toBe("xai-from-env");
+    expect(readFileSync).not.toHaveBeenCalled();
+  });
+
+  it("env set to empty/whitespace is treated as unset, so file fallback applies", () => {
+    process.env.GROK_API_KEY = "   ";
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "xai-from-file" }));
+
+    hydrateGrokApiKeyFromUserSettings();
+
+    expect(process.env.GROK_API_KEY).toBe("xai-from-file");
+  });
+
+  it("file missing (ENOENT) is fail-soft: no throw, env stays unset", () => {
+    const enoent = Object.assign(new Error("ENOENT"), { code: "ENOENT" });
+    vi.mocked(readFileSync).mockImplementationOnce(() => {
+      throw enoent;
+    });
+
+    expect(() => hydrateGrokApiKeyFromUserSettings()).not.toThrow();
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+  });
+
+  it("malformed JSON is fail-soft: no throw, env stays unset", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce("not json at all");
+
+    expect(() => hydrateGrokApiKeyFromUserSettings()).not.toThrow();
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+  });
+
+  it("apiKey absent is fail-soft: no throw, env stays unset", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({}));
+
+    expect(() => hydrateGrokApiKeyFromUserSettings()).not.toThrow();
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+  });
+
+  it("apiKey empty string is fail-soft: no throw, env stays unset", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "   " }));
+
+    expect(() => hydrateGrokApiKeyFromUserSettings()).not.toThrow();
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+  });
+
+  it("apiKey non-string is fail-soft: no throw, env stays unset", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: 12345 }));
+
+    expect(() => hydrateGrokApiKeyFromUserSettings()).not.toThrow();
+    expect(process.env.GROK_API_KEY).toBeUndefined();
+  });
+});
+
+describe("registerBuiltInGrokProvider — hydration wiring", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    process.env = { ...ORIGINAL_ENV };
+    delete process.env.GROK_API_KEY;
+  });
+
+  it("hydrates process.env.GROK_API_KEY from the settings file before registering", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "xai-from-file" }));
+    const registry = makeFakeRegistry();
+
+    registerBuiltInGrokProvider(registry);
+
+    expect(process.env.GROK_API_KEY).toBe("xai-from-file");
+    const registered = registry.registeredProviders.get(GROK_CLI_PROVIDER_ID) as typeof GROK_PROVIDER_REGISTRATION;
+    // No displacement: still registers grok-cli with the unchanged $GROK_API_KEY reference.
+    expect(registered.apiKey).toBe("$GROK_API_KEY");
+    expect(registered).toMatchObject({
+      name: "Grok",
+      baseUrl: "https://api.x.ai/v1",
+      api: "openai-completions",
+    });
+  });
+
+  it("is idempotent: a second call does not re-read or overwrite an already-hydrated env value", () => {
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "xai-from-file" }));
+    const registry = makeFakeRegistry();
+
+    registerBuiltInGrokProvider(registry);
+    expect(process.env.GROK_API_KEY).toBe("xai-from-file");
+    expect(readFileSync).toHaveBeenCalledTimes(1);
+
+    // Second call: env is now set, so the file must not be read again, and the value must
+    // not be clobbered even if the (mocked) file would return something else.
+    vi.mocked(readFileSync).mockReturnValueOnce(JSON.stringify({ apiKey: "xai-should-not-be-used" }));
+    registerBuiltInGrokProvider(registry);
+
+    expect(process.env.GROK_API_KEY).toBe("xai-from-file");
+    expect(readFileSync).toHaveBeenCalledTimes(1);
+  });
+
+  it("leaves an operator-provided GROK_API_KEY untouched", () => {
+    process.env.GROK_API_KEY = "xai-operator-provided";
+    const registry = makeFakeRegistry();
+
+    registerBuiltInGrokProvider(registry);
+
+    expect(process.env.GROK_API_KEY).toBe("xai-operator-provided");
+    expect(readFileSync).not.toHaveBeenCalled();
+  });
+});
diff --git a/packages/core/src/grok-provider.ts b/packages/core/src/grok-provider.ts
index 22902854b3..4de4d59a90 100644
--- a/packages/core/src/grok-provider.ts
+++ b/packages/core/src/grok-provider.ts
@@ -20,6 +20,10 @@
  * provider's model list wholesale rather than merging).
  */
 
+import { readFileSync } from "node:fs";
+import { homedir } from "node:os";
+import { join } from "node:path";
+
 export const GROK_CLI_PROVIDER_ID = "grok-cli";
 
 type GrokModelInput = "text" | "image";
@@ -173,10 +177,53 @@ function cloneGrokProviderRegistration(config: GrokProviderRegistration): GrokPr
  * registry" hard-fail this task fixes. Always pass a cloned config because pi's
  * registerProvider() stores and mutates the config object during later upserts.
  */
+/**
+ * FNXC:ProviderAuth 2026-07-09-00:00:
+ * FN-7714 honors a Grok API key stored in `~/.grok/user-settings.json` (`{ "apiKey": ... }`)
+ * when `GROK_API_KEY` is not set in the environment. `GROK_PROVIDER_REGISTRATION.apiKey` is
+ * the static env reference `"$GROK_API_KEY"`, which pi resolves from `process.env.GROK_API_KEY`
+ * at request time — so the fix hydrates that env var (never the provider config, which would
+ * leak the raw key via `/api/models`-style reads and logs) from the settings file, only when
+ * the env var is currently unset/empty. An already-set `GROK_API_KEY` always wins and the file
+ * is never read in that case. A missing (ENOENT), malformed, or empty/absent-`apiKey` settings
+ * file is fail-soft: never throw, never mutate env. This exactly mirrors the precedence and
+ * fail-soft behavior of `probeGrokApiKeyPresence` in
+ * `plugins/fusion-plugin-grok-runtime/src/probe.ts` (env-first, `.trim().length > 0`, same
+ * `~/.grok/user-settings.json` path), kept synchronous here because
+ * `registerBuiltInGrokProvider` itself is synchronous.
+ */
+export function hydrateGrokApiKeyFromUserSettings(
+  logWarning: (message: string) => void = () => {},
+): void {
+  const envKey = process.env.GROK_API_KEY;
+  if (typeof envKey === "string" && envKey.trim().length > 0) {
+    // Env var always wins; never read or overwrite from the settings file.
+    return;
+  }
+
+  try {
+    const settingsPath = join(homedir(), ".grok", "user-settings.json");
+    const raw = readFileSync(settingsPath, "utf-8");
+    const parsed = JSON.parse(raw) as { apiKey?: unknown };
+    if (typeof parsed?.apiKey === "string" && parsed.apiKey.trim().length > 0) {
+      process.env.GROK_API_KEY = parsed.apiKey.trim();
+    }
+  } catch (error) {
+    // Fail-soft: a missing (ENOENT), malformed, or unreadable settings file must never throw
+    // or mutate process.env — only unexpected errors are worth a warning; ENOENT is routine.
+    const isEnoent = (error as NodeJS.ErrnoException | undefined)?.code === "ENOENT";
+    if (!isEnoent) {
+      const message = error instanceof Error ? error.message : String(error);
+      logWarning(`Failed to read ~/.grok/user-settings.json for GROK_API_KEY fallback: ${message}`);
+    }
+  }
+}
+
 export function registerBuiltInGrokProvider(
   modelRegistry: GrokModelRegistryLike,
   logWarning: (message: string) => void = () => {},
 ): void {
+  hydrateGrokApiKeyFromUserSettings(logWarning);
   try {
     modelRegistry.registerProvider(GROK_CLI_PROVIDER_ID, cloneGrokProviderRegistration(GROK_PROVIDER_REGISTRATION));
   } catch (error) {