diff --git a/apps/web/src/app/onboarding/layout.tsx b/apps/web/src/app/onboarding/layout.tsx
new file mode 100644
index 0000000..f094fce
--- /dev/null
+++ b/apps/web/src/app/onboarding/layout.tsx
@@ -0,0 +1,9 @@
+import type { ReactNode } from "react";
+
+export default function OnboardingLayout({ children }: { children: ReactNode }): React.JSX.Element {
+  return (
+    <main className="flex min-h-screen items-center justify-center bg-gradient-to-b from-slate-50 to-white p-4 sm:p-6">
+      <div className="w-full max-w-3xl">{children}</div>
+    </main>
+  );
+}
diff --git a/apps/web/src/app/onboarding/page.tsx b/apps/web/src/app/onboarding/page.tsx
new file mode 100644
index 0000000..2afbdd9
--- /dev/null
+++ b/apps/web/src/app/onboarding/page.tsx
@@ -0,0 +1,36 @@
+import { redirect } from "next/navigation";
+import { OnboardingWizard } from "@/components/onboarding/OnboardingWizard";
+import { API_BASE_URL } from "@/lib/config";
+
+export const dynamic = "force-dynamic";
+
+interface OnboardingStatusResponse {
+  completed: boolean;
+}
+
+async function getOnboardingStatus(): Promise<OnboardingStatusResponse> {
+  try {
+    const response = await fetch(`${API_BASE_URL}/api/onboarding/status`, {
+      method: "GET",
+      cache: "no-store",
+    });
+
+    if (!response.ok) {
+      return { completed: false };
+    }
+
+    return (await response.json()) as OnboardingStatusResponse;
+  } catch {
+    return { completed: false };
+  }
+}
+
+export default async function OnboardingPage(): Promise<React.JSX.Element> {
+  const status = await getOnboardingStatus();
+
+  if (status.completed) {
+    redirect("/");
+  }
+
+  return <OnboardingWizard />;
+}
diff --git a/apps/web/src/components/onboarding/OnboardingWizard.test.tsx b/apps/web/src/components/onboarding/OnboardingWizard.test.tsx
new file mode 100644
index 0000000..e36124d
--- /dev/null
+++ b/apps/web/src/components/onboarding/OnboardingWizard.test.tsx
@@ -0,0 +1,106 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { render, screen, waitFor } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { OnboardingWizard } from "./OnboardingWizard";
+
+const mockPush = vi.fn();
+const mockGetStatus = vi.fn();
+const mockCreateBreakglass = vi.fn();
+const mockConfigureOidc = vi.fn();
+const mockTestProvider = vi.fn();
+const mockAddProvider = vi.fn();
+const mockCompleteOnboarding = vi.fn();
+
+vi.mock("next/navigation", () => ({
+  useRouter: (): { push: typeof mockPush } => ({
+    push: mockPush,
+  }),
+}));
+
+vi.mock("@/lib/api/onboarding", () => ({
+  fetchOnboardingStatus: (): ReturnType<typeof mockGetStatus> => mockGetStatus(),
+  createBreakglassAdmin: (...args: unknown[]): ReturnType<typeof mockCreateBreakglass> =>
+    mockCreateBreakglass(...args),
+  configureOidcProvider: (...args: unknown[]): ReturnType<typeof mockConfigureOidc> =>
+    mockConfigureOidc(...args),
+  testOnboardingProvider: (...args: unknown[]): ReturnType<typeof mockTestProvider> =>
+    mockTestProvider(...args),
+  addOnboardingProvider: (...args: unknown[]): ReturnType<typeof mockAddProvider> =>
+    mockAddProvider(...args),
+  completeOnboarding: (): ReturnType<typeof mockCompleteOnboarding> => mockCompleteOnboarding(),
+}));
+
+describe("OnboardingWizard", () => {
+  beforeEach(() => {
+    mockPush.mockReset();
+    mockGetStatus.mockReset();
+    mockCreateBreakglass.mockReset();
+    mockConfigureOidc.mockReset();
+    mockTestProvider.mockReset();
+    mockAddProvider.mockReset();
+    mockCompleteOnboarding.mockReset();
+
+    mockGetStatus.mockResolvedValue({ completed: false });
+    mockCreateBreakglass.mockResolvedValue({ id: "bg-1", username: "admin" });
+    mockConfigureOidc.mockResolvedValue(undefined);
+    mockTestProvider.mockResolvedValue({ success: true });
+    mockAddProvider.mockResolvedValue({ id: "provider-1" });
+    mockCompleteOnboarding.mockResolvedValue(undefined);
+  });
+
+  it("renders the first step with admin setup fields", async () => {
+    render(<OnboardingWizard />);
+
+    expect(
+      await screen.findByText("Welcome to Mosaic Stack. Let's get you set up.")
+    ).toBeInTheDocument();
+    expect(screen.getByLabelText("Username")).toBeInTheDocument();
+    expect(screen.getByLabelText("Password")).toBeInTheDocument();
+    expect(screen.getByLabelText("Confirm Password")).toBeInTheDocument();
+    expect(screen.getByText("1. Admin")).toBeInTheDocument();
+  });
+
+  it("validates admin form fields before submit", async () => {
+    const user = userEvent.setup();
+    render(<OnboardingWizard />);
+
+    await screen.findByText("Welcome to Mosaic Stack. Let's get you set up.");
+    await user.click(screen.getByRole("button", { name: "Create Admin" }));
+
+    expect(screen.getByText("Username must be at least 3 characters.")).toBeInTheDocument();
+    expect(mockCreateBreakglass).not.toHaveBeenCalled();
+  });
+
+  it("supports happy path with OIDC skipped", async () => {
+    const user = userEvent.setup();
+    render(<OnboardingWizard />);
+
+    await screen.findByText("Welcome to Mosaic Stack. Let's get you set up.");
+
+    await user.type(screen.getByLabelText("Username"), "admin");
+    await user.type(screen.getByLabelText("Password"), "verysecurepassword");
+    await user.type(screen.getByLabelText("Confirm Password"), "verysecurepassword");
+    await user.click(screen.getByRole("button", { name: "Create Admin" }));
+
+    await screen.findByText("Configure OIDC Provider (Optional)");
+    await user.click(screen.getByRole("button", { name: "Skip" }));
+
+    await screen.findByText("Add Your First LLM Provider");
+    await user.type(screen.getByLabelText("Display Name"), "My OpenAI");
+    await user.type(screen.getByLabelText("API Key"), "sk-test-key");
+
+    await user.click(screen.getByRole("button", { name: "Test Connection" }));
+    await screen.findByText("Connection successful.");
+
+    const addProviderButton = screen.getByRole("button", { name: "Add Provider" });
+    expect(addProviderButton).toBeEnabled();
+    await user.click(addProviderButton);
+
+    await screen.findByText("You're all set");
+    await user.click(screen.getByRole("button", { name: "Launch Mosaic Stack" }));
+
+    await waitFor(() => {
+      expect(mockPush).toHaveBeenCalledWith("/");
+    });
+  });
+});
diff --git a/apps/web/src/components/onboarding/OnboardingWizard.tsx b/apps/web/src/components/onboarding/OnboardingWizard.tsx
new file mode 100644
index 0000000..764ef8d
--- /dev/null
+++ b/apps/web/src/components/onboarding/OnboardingWizard.tsx
@@ -0,0 +1,791 @@
+"use client";
+
+import { useEffect, useMemo, useState } from "react";
+import { Check, Loader2 } from "lucide-react";
+import { useRouter } from "next/navigation";
+import { Button } from "@/components/ui/button";
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
+import { Input } from "@/components/ui/input";
+import { Label } from "@/components/ui/label";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
+import {
+  addOnboardingProvider,
+  completeOnboarding,
+  configureOidcProvider,
+  createBreakglassAdmin,
+  fetchOnboardingStatus,
+  testOnboardingProvider,
+} from "@/lib/api/onboarding";
+
+type WizardStep = 1 | 2 | 3 | 4;
+type ProviderType = "openai" | "anthropic" | "zai" | "ollama" | "custom";
+
+interface StepDefinition {
+  id: WizardStep;
+  label: string;
+}
+
+interface ProviderOption {
+  value: ProviderType;
+  label: string;
+}
+
+const STEPS: StepDefinition[] = [
+  { id: 1, label: "1. Admin" },
+  { id: 2, label: "2. Auth" },
+  { id: 3, label: "3. Provider" },
+  { id: 4, label: "4. Launch" },
+];
+
+const PROVIDER_OPTIONS: ProviderOption[] = [
+  { value: "openai", label: "OpenAI" },
+  { value: "anthropic", label: "Anthropic" },
+  { value: "zai", label: "Z.ai" },
+  { value: "ollama", label: "Ollama" },
+  { value: "custom", label: "Custom" },
+];
+
+const CLOUD_PROVIDER_TYPES = new Set<ProviderType>(["openai", "anthropic", "zai"]);
+const BASE_URL_PROVIDER_TYPES = new Set<ProviderType>(["ollama", "custom"]);
+
+function getErrorMessage(error: unknown, fallback: string): string {
+  if (error instanceof Error && error.message.trim().length > 0) {
+    return error.message;
+  }
+
+  return fallback;
+}
+
+function isValidHttpUrl(value: string): boolean {
+  try {
+    const parsed = new URL(value);
+    return parsed.protocol === "http:" || parsed.protocol === "https:";
+  } catch {
+    return false;
+  }
+}
+
+function mapProviderTypeToApi(type: ProviderType): string {
+  switch (type) {
+    case "anthropic":
+      return "claude";
+    case "zai":
+      return "openai";
+    case "custom":
+      return "openai";
+    default:
+      return type;
+  }
+}
+
+function getProviderDefaultBaseUrl(type: ProviderType): string | undefined {
+  switch (type) {
+    case "ollama":
+      return "http://localhost:11434";
+    case "anthropic":
+      return "https://api.anthropic.com/v1";
+    case "zai":
+      return "https://api.z.ai/v1";
+    default:
+      return undefined;
+  }
+}
+
+function buildProviderName(displayName: string, type: ProviderType): string {
+  const slug = displayName
+    .trim()
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, "-")
+    .replace(/^-+/, "")
+    .replace(/-+$/, "");
+
+  if (slug.length > 0) {
+    return slug;
+  }
+
+  return `${type}-provider`;
+}
+
+function constantTimeEquals(left: string, right: string): boolean {
+  if (left.length !== right.length) {
+    return false;
+  }
+
+  let mismatch = 0;
+  for (let index = 0; index < left.length; index += 1) {
+    mismatch |= left.charCodeAt(index) ^ right.charCodeAt(index);
+  }
+
+  return mismatch === 0;
+}
+
+export function OnboardingWizard(): React.JSX.Element {
+  const router = useRouter();
+
+  const [currentStep, setCurrentStep] = useState<WizardStep>(1);
+  const [isCheckingStatus, setIsCheckingStatus] = useState(true);
+
+  const [username, setUsername] = useState("");
+  const [password, setPassword] = useState("");
+  const [confirmPassword, setConfirmPassword] = useState("");
+  const [isCreatingAdmin, setIsCreatingAdmin] = useState(false);
+  const [configuredUsername, setConfiguredUsername] = useState<string | null>(null);
+
+  const [issuerUrl, setIssuerUrl] = useState("");
+  const [clientId, setClientId] = useState("");
+  const [clientSecret, setClientSecret] = useState("");
+  const [isConfiguringOidc, setIsConfiguringOidc] = useState(false);
+  const [oidcConfigured, setOidcConfigured] = useState(false);
+
+  const [providerType, setProviderType] = useState<ProviderType>("openai");
+  const [displayName, setDisplayName] = useState("");
+  const [providerApiKey, setProviderApiKey] = useState("");
+  const [providerBaseUrl, setProviderBaseUrl] = useState("");
+  const [isTestingProvider, setIsTestingProvider] = useState(false);
+  const [isAddingProvider, setIsAddingProvider] = useState(false);
+  const [providerConfigured, setProviderConfigured] = useState<{
+    displayName: string;
+    type: ProviderType;
+  } | null>(null);
+  const [providerTestMessage, setProviderTestMessage] = useState<string | null>(null);
+  const [providerTestSucceeded, setProviderTestSucceeded] = useState(false);
+  const [testedProviderSignature, setTestedProviderSignature] = useState<string | null>(null);
+
+  const [isCompleting, setIsCompleting] = useState(false);
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
+
+  const requiresApiKey = CLOUD_PROVIDER_TYPES.has(providerType);
+  const requiresBaseUrl = BASE_URL_PROVIDER_TYPES.has(providerType);
+  const apiProviderType = mapProviderTypeToApi(providerType);
+  const resolvedProviderBaseUrl =
+    requiresBaseUrl && providerBaseUrl.trim().length > 0
+      ? providerBaseUrl.trim()
+      : getProviderDefaultBaseUrl(providerType);
+
+  const providerTestPayload = useMemo(() => {
+    const payload: { type: string; baseUrl?: string; apiKey?: string } = {
+      type: apiProviderType,
+    };
+
+    if (resolvedProviderBaseUrl !== undefined && resolvedProviderBaseUrl.length > 0) {
+      payload.baseUrl = resolvedProviderBaseUrl;
+    }
+
+    const trimmedApiKey = providerApiKey.trim();
+    if (requiresApiKey && trimmedApiKey.length > 0) {
+      payload.apiKey = trimmedApiKey;
+    }
+
+    return payload;
+  }, [apiProviderType, providerApiKey, requiresApiKey, resolvedProviderBaseUrl]);
+
+  const providerPayloadSignature = useMemo(
+    () => JSON.stringify(providerTestPayload),
+    [providerTestPayload]
+  );
+
+  const canAddProvider =
+    providerTestSucceeded &&
+    testedProviderSignature === providerPayloadSignature &&
+    !isTestingProvider &&
+    !isAddingProvider;
+
+  useEffect(() => {
+    let cancelled = false;
+
+    async function loadStatus(): Promise<void> {
+      try {
+        const status = await fetchOnboardingStatus();
+        if (!cancelled && status.completed) {
+          router.push("/");
+          return;
+        }
+      } catch {
+        // Status check failure should not block setup UI.
+      } finally {
+        if (!cancelled) {
+          setIsCheckingStatus(false);
+        }
+      }
+    }
+
+    void loadStatus();
+
+    return (): void => {
+      cancelled = true;
+    };
+  }, [router]);
+
+  const resetProviderVerification = (): void => {
+    setProviderTestSucceeded(false);
+    setTestedProviderSignature(null);
+    setProviderTestMessage(null);
+  };
+
+  const validateAdminStep = (): boolean => {
+    if (username.trim().length < 3) {
+      setErrorMessage("Username must be at least 3 characters.");
+      return false;
+    }
+
+    if (password.length < 8) {
+      setErrorMessage("Password must be at least 8 characters.");
+      return false;
+    }
+
+    if (!constantTimeEquals(password, confirmPassword)) {
+      setErrorMessage("Passwords do not match.");
+      return false;
+    }
+
+    return true;
+  };
+
+  const validateOidcStep = (): boolean => {
+    if (issuerUrl.trim().length === 0 || !isValidHttpUrl(issuerUrl.trim())) {
+      setErrorMessage("Issuer URL must be a valid URL.");
+      return false;
+    }
+
+    if (clientId.trim().length === 0) {
+      setErrorMessage("Client ID is required.");
+      return false;
+    }
+
+    if (clientSecret.trim().length === 0) {
+      setErrorMessage("Client secret is required.");
+      return false;
+    }
+
+    return true;
+  };
+
+  const validateProviderStep = (): boolean => {
+    if (displayName.trim().length === 0) {
+      setErrorMessage("Display name is required.");
+      return false;
+    }
+
+    if (requiresApiKey && providerApiKey.trim().length === 0) {
+      setErrorMessage("API key is required for this provider.");
+      return false;
+    }
+
+    if (requiresBaseUrl && providerBaseUrl.trim().length === 0) {
+      setErrorMessage("Base URL is required for this provider.");
+      return false;
+    }
+
+    if (requiresBaseUrl && !isValidHttpUrl(providerBaseUrl.trim())) {
+      setErrorMessage("Base URL must be a valid URL.");
+      return false;
+    }
+
+    return true;
+  };
+
+  const handleCreateAdmin = async (event: React.SyntheticEvent<HTMLFormElement>): Promise<void> => {
+    event.preventDefault();
+
+    setErrorMessage(null);
+    if (!validateAdminStep()) {
+      return;
+    }
+
+    setIsCreatingAdmin(true);
+    try {
+      const result = await createBreakglassAdmin({
+        username: username.trim(),
+        password,
+      });
+      setConfiguredUsername(result.username);
+      setCurrentStep(2);
+    } catch (error) {
+      setErrorMessage(getErrorMessage(error, "Failed to create admin account."));
+    } finally {
+      setIsCreatingAdmin(false);
+    }
+  };
+
+  const handleConfigureOidc = async (
+    event: React.SyntheticEvent<HTMLFormElement>
+  ): Promise<void> => {
+    event.preventDefault();
+
+    setErrorMessage(null);
+    if (!validateOidcStep()) {
+      return;
+    }
+
+    setIsConfiguringOidc(true);
+    try {
+      await configureOidcProvider({
+        issuerUrl: issuerUrl.trim(),
+        clientId: clientId.trim(),
+        clientSecret: clientSecret.trim(),
+      });
+      setOidcConfigured(true);
+      setCurrentStep(3);
+    } catch (error) {
+      setErrorMessage(getErrorMessage(error, "Failed to configure OIDC provider."));
+    } finally {
+      setIsConfiguringOidc(false);
+    }
+  };
+
+  const handleSkipOidc = (): void => {
+    setErrorMessage(null);
+    setOidcConfigured(false);
+    setCurrentStep(3);
+  };
+
+  const handleTestProvider = async (): Promise<void> => {
+    setErrorMessage(null);
+    setProviderTestMessage(null);
+    if (!validateProviderStep()) {
+      return;
+    }
+
+    setIsTestingProvider(true);
+    try {
+      const response = await testOnboardingProvider(providerTestPayload);
+      if (!response.success) {
+        setProviderTestSucceeded(false);
+        setTestedProviderSignature(null);
+        setErrorMessage(response.error ?? "Connection test failed.");
+        return;
+      }
+
+      setProviderTestSucceeded(true);
+      setTestedProviderSignature(providerPayloadSignature);
+      setProviderTestMessage("Connection successful.");
+    } catch (error) {
+      setProviderTestSucceeded(false);
+      setTestedProviderSignature(null);
+      setErrorMessage(getErrorMessage(error, "Connection test failed."));
+    } finally {
+      setIsTestingProvider(false);
+    }
+  };
+
+  const handleAddProvider = async (): Promise<void> => {
+    setErrorMessage(null);
+    if (!validateProviderStep()) {
+      return;
+    }
+
+    if (!canAddProvider) {
+      setErrorMessage("Test connection successfully before adding the provider.");
+      return;
+    }
+
+    setIsAddingProvider(true);
+    try {
+      const trimmedDisplayName = displayName.trim();
+      const payload: {
+        name: string;
+        displayName: string;
+        type: string;
+        baseUrl?: string;
+        apiKey?: string;
+      } = {
+        name: buildProviderName(trimmedDisplayName, providerType),
+        displayName: trimmedDisplayName,
+        type: apiProviderType,
+      };
+
+      if (resolvedProviderBaseUrl !== undefined && resolvedProviderBaseUrl.length > 0) {
+        payload.baseUrl = resolvedProviderBaseUrl;
+      }
+
+      const trimmedApiKey = providerApiKey.trim();
+      if (requiresApiKey && trimmedApiKey.length > 0) {
+        payload.apiKey = trimmedApiKey;
+      }
+
+      await addOnboardingProvider(payload);
+
+      setProviderConfigured({ displayName: trimmedDisplayName, type: providerType });
+      setCurrentStep(4);
+    } catch (error) {
+      setErrorMessage(getErrorMessage(error, "Failed to add provider."));
+    } finally {
+      setIsAddingProvider(false);
+    }
+  };
+
+  const handleCompleteOnboarding = async (): Promise<void> => {
+    setErrorMessage(null);
+    setIsCompleting(true);
+    try {
+      await completeOnboarding();
+      router.push("/");
+    } catch (error) {
+      setErrorMessage(getErrorMessage(error, "Failed to complete onboarding."));
+    } finally {
+      setIsCompleting(false);
+    }
+  };
+
+  const providerLabel =
+    PROVIDER_OPTIONS.find((option) => option.value === providerConfigured?.type)?.label ??
+    providerConfigured?.type ??
+    "Unknown";
+
+  return (
+    <Card className="mx-auto w-full max-w-2xl shadow-sm">
+      <CardHeader>
+        <CardTitle>First-boot onboarding</CardTitle>
+        <CardDescription>Set up your admin access, auth, and first provider.</CardDescription>
+      </CardHeader>
+      <CardContent className="space-y-6">
+        <div className="grid grid-cols-2 gap-2 sm:grid-cols-4">
+          {STEPS.map((step) => {
+            const isActive = currentStep === step.id;
+            const isComplete = currentStep > step.id;
+            const badgeClass = isComplete
+              ? "bg-emerald-100 text-emerald-700 border-emerald-200"
+              : isActive
+                ? "bg-blue-100 text-blue-700 border-blue-200"
+                : "bg-gray-100 text-gray-500 border-gray-200";
+
+            return (
+              <div
+                key={step.id}
+                className={`rounded-md border px-3 py-2 text-sm ${badgeClass}`}
+                aria-current={isActive ? "step" : undefined}
+              >
+                <div className="flex items-center gap-2 font-medium">
+                  <span className="inline-flex h-5 w-5 items-center justify-center rounded-full border border-current text-xs">
+                    {isComplete ? <Check className="h-3.5 w-3.5" aria-hidden="true" /> : step.id}
+                  </span>
+                  <span>{step.label}</span>
+                </div>
+              </div>
+            );
+          })}
+        </div>
+
+        {isCheckingStatus ? (
+          <div className="flex items-center gap-2 text-sm text-gray-600">
+            <Loader2 className="h-4 w-4 animate-spin" aria-hidden="true" />
+            <span>Checking onboarding status...</span>
+          </div>
+        ) : (
+          <>
+            {currentStep === 1 && (
+              <form onSubmit={handleCreateAdmin} className="space-y-4" noValidate>
+                <div className="space-y-1">
+                  <h2 className="text-xl font-semibold">
+                    Welcome to Mosaic Stack. Let's get you set up.
+                  </h2>
+                  <p className="text-sm text-gray-600">
+                    Create a breakglass admin account for emergency access.
+                  </p>
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-username">Username</Label>
+                  <Input
+                    id="onboarding-username"
+                    value={username}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setUsername(event.target.value);
+                    }}
+                    disabled={isCreatingAdmin}
+                    autoComplete="username"
+                  />
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-password">Password</Label>
+                  <Input
+                    id="onboarding-password"
+                    type="password"
+                    value={password}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setPassword(event.target.value);
+                    }}
+                    disabled={isCreatingAdmin}
+                    autoComplete="new-password"
+                  />
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-confirm-password">Confirm Password</Label>
+                  <Input
+                    id="onboarding-confirm-password"
+                    type="password"
+                    value={confirmPassword}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setConfirmPassword(event.target.value);
+                    }}
+                    disabled={isCreatingAdmin}
+                    autoComplete="new-password"
+                  />
+                </div>
+
+                <Button type="submit" disabled={isCreatingAdmin}>
+                  {isCreatingAdmin && (
+                    <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />
+                  )}
+                  <span>Create Admin</span>
+                </Button>
+              </form>
+            )}
+
+            {currentStep === 2 && (
+              <form onSubmit={handleConfigureOidc} className="space-y-4" noValidate>
+                <div className="space-y-1">
+                  <h2 className="text-xl font-semibold">Configure OIDC Provider (Optional)</h2>
+                  <p className="text-sm text-gray-600">
+                    You can skip this for now and continue with breakglass-only authentication.
+                  </p>
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-issuer-url">OIDC Issuer URL</Label>
+                  <Input
+                    id="onboarding-issuer-url"
+                    value={issuerUrl}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setIssuerUrl(event.target.value);
+                    }}
+                    disabled={isConfiguringOidc}
+                    placeholder="https://auth.example.com/application/o/mosaic/"
+                    autoComplete="url"
+                  />
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-client-id">Client ID</Label>
+                  <Input
+                    id="onboarding-client-id"
+                    value={clientId}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setClientId(event.target.value);
+                    }}
+                    disabled={isConfiguringOidc}
+                  />
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-client-secret">Client Secret</Label>
+                  <Input
+                    id="onboarding-client-secret"
+                    type="password"
+                    value={clientSecret}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setClientSecret(event.target.value);
+                    }}
+                    disabled={isConfiguringOidc}
+                    autoComplete="off"
+                  />
+                </div>
+
+                <div className="flex flex-wrap gap-2">
+                  <Button type="submit" disabled={isConfiguringOidc}>
+                    {isConfiguringOidc && (
+                      <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />
+                    )}
+                    <span>Configure OIDC</span>
+                  </Button>
+                  <Button
+                    type="button"
+                    variant="outline"
+                    onClick={handleSkipOidc}
+                    disabled={isConfiguringOidc}
+                  >
+                    Skip
+                  </Button>
+                </div>
+              </form>
+            )}
+
+            {currentStep === 3 && (
+              <div className="space-y-4">
+                <div className="space-y-1">
+                  <h2 className="text-xl font-semibold">Add Your First LLM Provider</h2>
+                  <p className="text-sm text-gray-600">
+                    Test the connection before adding your provider.
+                  </p>
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-provider-type">Provider Type</Label>
+                  <Select
+                    value={providerType}
+                    onValueChange={(value) => {
+                      const nextType = value as ProviderType;
+                      setProviderType(nextType);
+                      setProviderApiKey("");
+                      setProviderBaseUrl(
+                        BASE_URL_PROVIDER_TYPES.has(nextType)
+                          ? (getProviderDefaultBaseUrl(nextType) ?? "")
+                          : ""
+                      );
+                      resetProviderVerification();
+                      setErrorMessage(null);
+                    }}
+                    disabled={isTestingProvider || isAddingProvider}
+                  >
+                    <SelectTrigger id="onboarding-provider-type">
+                      <SelectValue placeholder="Select provider type" />
+                    </SelectTrigger>
+                    <SelectContent>
+                      {PROVIDER_OPTIONS.map((option) => (
+                        <SelectItem key={option.value} value={option.value}>
+                          {option.label}
+                        </SelectItem>
+                      ))}
+                    </SelectContent>
+                  </Select>
+                </div>
+
+                <div className="grid gap-2">
+                  <Label htmlFor="onboarding-provider-display-name">Display Name</Label>
+                  <Input
+                    id="onboarding-provider-display-name"
+                    value={displayName}
+                    onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                      setDisplayName(event.target.value);
+                      resetProviderVerification();
+                      setErrorMessage(null);
+                    }}
+                    disabled={isTestingProvider || isAddingProvider}
+                    placeholder="My OpenAI Provider"
+                  />
+                </div>
+
+                {requiresApiKey && (
+                  <div className="grid gap-2">
+                    <Label htmlFor="onboarding-provider-api-key">API Key</Label>
+                    <Input
+                      id="onboarding-provider-api-key"
+                      type="password"
+                      value={providerApiKey}
+                      onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                        setProviderApiKey(event.target.value);
+                        resetProviderVerification();
+                        setErrorMessage(null);
+                      }}
+                      disabled={isTestingProvider || isAddingProvider}
+                      autoComplete="off"
+                    />
+                  </div>
+                )}
+
+                {requiresBaseUrl && (
+                  <div className="grid gap-2">
+                    <Label htmlFor="onboarding-provider-base-url">Base URL</Label>
+                    <Input
+                      id="onboarding-provider-base-url"
+                      value={providerBaseUrl}
+                      onChange={(event: React.ChangeEvent<HTMLInputElement>) => {
+                        setProviderBaseUrl(event.target.value);
+                        resetProviderVerification();
+                        setErrorMessage(null);
+                      }}
+                      disabled={isTestingProvider || isAddingProvider}
+                      placeholder="http://localhost:11434"
+                      autoComplete="url"
+                    />
+                  </div>
+                )}
+
+                {providerTestMessage && (
+                  <p className="text-sm text-emerald-700" role="status">
+                    {providerTestMessage}
+                  </p>
+                )}
+
+                <div className="flex flex-wrap gap-2">
+                  <Button
+                    type="button"
+                    variant="outline"
+                    onClick={() => {
+                      void handleTestProvider();
+                    }}
+                    disabled={isTestingProvider || isAddingProvider}
+                  >
+                    {isTestingProvider && (
+                      <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />
+                    )}
+                    <span>Test Connection</span>
+                  </Button>
+                  <Button
+                    type="button"
+                    onClick={() => {
+                      void handleAddProvider();
+                    }}
+                    disabled={!canAddProvider}
+                  >
+                    {isAddingProvider && (
+                      <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />
+                    )}
+                    <span>Add Provider</span>
+                  </Button>
+                </div>
+              </div>
+            )}
+
+            {currentStep === 4 && (
+              <div className="space-y-4">
+                <div className="space-y-1">
+                  <h2 className="text-xl font-semibold">You're all set</h2>
+                  <p className="text-sm text-gray-600">
+                    Review the setup summary and launch Mosaic Stack.
+                  </p>
+                </div>
+
+                <div className="rounded-md border bg-gray-50 p-4">
+                  <ul className="space-y-2 text-sm">
+                    <li>
+                      <span className="font-medium">Admin:</span>{" "}
+                      {configuredUsername ? `${configuredUsername} configured` : "Not configured"}
+                    </li>
+                    <li>
+                      <span className="font-medium">OIDC:</span>{" "}
+                      {oidcConfigured ? "Configured" : "Skipped for now"}
+                    </li>
+                    <li>
+                      <span className="font-medium">LLM Provider:</span>{" "}
+                      {providerConfigured
+                        ? `${providerConfigured.displayName} (${providerLabel})`
+                        : "Not configured"}
+                    </li>
+                  </ul>
+                </div>
+
+                <Button
+                  type="button"
+                  onClick={() => void handleCompleteOnboarding()}
+                  disabled={isCompleting}
+                >
+                  {isCompleting && (
+                    <Loader2 className="mr-2 h-4 w-4 animate-spin" aria-hidden="true" />
+                  )}
+                  <span>Launch Mosaic Stack</span>
+                </Button>
+              </div>
+            )}
+          </>
+        )}
+
+        {errorMessage && (
+          <p className="text-sm text-red-600" role="alert">
+            {errorMessage}
+          </p>
+        )}
+      </CardContent>
+    </Card>
+  );
+}
+
+export default OnboardingWizard;
diff --git a/apps/web/src/lib/api/onboarding.ts b/apps/web/src/lib/api/onboarding.ts
new file mode 100644
index 0000000..0cc4a95
--- /dev/null
+++ b/apps/web/src/lib/api/onboarding.ts
@@ -0,0 +1,80 @@
+import { apiGet, apiPost } from "./client";
+
+export interface OnboardingStatus {
+  completed: boolean;
+}
+
+export interface BreakglassAdminRequest {
+  username: string;
+  password: string;
+}
+
+export interface BreakglassAdminResponse {
+  id: string;
+  username: string;
+}
+
+export interface ConfigureOidcRequest {
+  issuerUrl: string;
+  clientId: string;
+  clientSecret: string;
+}
+
+export interface ProviderModel {
+  id: string;
+  name?: string;
+}
+
+export interface AddOnboardingProviderRequest {
+  name: string;
+  displayName: string;
+  type: string;
+  baseUrl?: string;
+  apiKey?: string;
+  models?: ProviderModel[];
+}
+
+export interface AddOnboardingProviderResponse {
+  id: string;
+}
+
+export interface TestOnboardingProviderRequest {
+  type: string;
+  baseUrl?: string;
+  apiKey?: string;
+}
+
+export interface TestOnboardingProviderResponse {
+  success: boolean;
+  error?: string;
+}
+
+export async function fetchOnboardingStatus(): Promise<OnboardingStatus> {
+  return apiGet<OnboardingStatus>("/api/onboarding/status");
+}
+
+export async function createBreakglassAdmin(
+  request: BreakglassAdminRequest
+): Promise<BreakglassAdminResponse> {
+  return apiPost<BreakglassAdminResponse>("/api/onboarding/breakglass", request);
+}
+
+export async function configureOidcProvider(request: ConfigureOidcRequest): Promise<void> {
+  await apiPost<unknown>("/api/onboarding/oidc", request);
+}
+
+export async function addOnboardingProvider(
+  request: AddOnboardingProviderRequest
+): Promise<AddOnboardingProviderResponse> {
+  return apiPost<AddOnboardingProviderResponse>("/api/onboarding/provider", request);
+}
+
+export async function testOnboardingProvider(
+  request: TestOnboardingProviderRequest
+): Promise<TestOnboardingProviderResponse> {
+  return apiPost<TestOnboardingProviderResponse>("/api/onboarding/provider/test", request);
+}
+
+export async function completeOnboarding(): Promise<void> {
+  await apiPost<unknown>("/api/onboarding/complete");
+}