diff --git a/src/app/layout.tsx b/src/app/layout.tsx
index 617a688..c5c9ea5 100644
--- a/src/app/layout.tsx
+++ b/src/app/layout.tsx
@@ -4,6 +4,7 @@ import './globals.css'
 import { ThemeProvider } from '@/components/theme-provider'
 import { AuthProvider } from '@/context/auth-context'
 import { AppToastProvider } from '@/context/toast-context'
+import { OnboardingProvider } from '@/context/onboarding-context'
 import { SetupGuard } from '@/components/setup-guard'
 
 const sourceCodePro = Source_Code_Pro({
@@ -55,7 +56,9 @@ export default function RootLayout({
         >
           <AuthProvider>
             <AppToastProvider>
-              <SetupGuard>{children}</SetupGuard>
+              <OnboardingProvider>
+                <SetupGuard>{children}</SetupGuard>
+              </OnboardingProvider>
             </AppToastProvider>
           </AuthProvider>
         </ThemeProvider>
diff --git a/src/app/new/page.test.tsx b/src/app/new/page.test.tsx
index e34656b..e97ee95 100644
--- a/src/app/new/page.test.tsx
+++ b/src/app/new/page.test.tsx
@@ -6,8 +6,13 @@ import { describe, it, expect, vi, beforeAll, beforeEach, afterAll, afterEach }
 import { render, screen, cleanup } from '@testing-library/react'
 import { setupServer } from 'msw/node'
 import { handlers } from '@/mocks/handlers'
+import { createMockOnboardingContext } from '@/test/mock-onboarding'
 import NewTopicPage from './page'
 
+vi.mock('@/context/onboarding-context', () => ({
+  useOnboardingContext: () => createMockOnboardingContext(),
+}))
+
 const server = setupServer(...handlers)
 
 const mockStorage: Record<string, string> = {}
diff --git a/src/app/new/page.tsx b/src/app/new/page.tsx
index 389d820..fd2774f 100644
--- a/src/app/new/page.tsx
+++ b/src/app/new/page.tsx
@@ -7,7 +7,7 @@
 
 'use client'
 
-import { useState, useRef, useEffect } from 'react'
+import { useState, useEffect } from 'react'
 import { useRouter, useSearchParams } from 'next/navigation'
 import type { CreateTopicInput } from '@/lib/api/types'
 import { createTopic, getPublicSettings } from '@/lib/api/client'
@@ -15,8 +15,7 @@ import { getTopicUrl } from '@/lib/format'
 import { ForumLayout } from '@/components/layout/forum-layout'
 import { Breadcrumbs } from '@/components/breadcrumbs'
 import { TopicForm } from '@/components/topic-form'
-import { OnboardingModal } from '@/components/onboarding-modal'
-import { useOnboarding } from '@/hooks/use-onboarding'
+import { useOnboardingContext } from '@/context/onboarding-context'
 import { useAuth } from '@/hooks/use-auth'
 
 export default function NewTopicPage() {
@@ -24,11 +23,10 @@ export default function NewTopicPage() {
   const searchParams = useSearchParams()
   const initialCategory = searchParams.get('category') ?? ''
   const { getAccessToken } = useAuth()
+  const { ensureOnboarded } = useOnboardingContext()
   const [submitting, setSubmitting] = useState(false)
   const [error, setError] = useState<string | null>(null)
   const [communityName, setCommunityName] = useState('')
-  const onboarding = useOnboarding()
-  const pendingValues = useRef<CreateTopicInput | null>(null)
 
   useEffect(() => {
     getPublicSettings()
@@ -36,7 +34,9 @@ export default function NewTopicPage() {
       .catch(() => {})
   }, [])
 
-  const doSubmit = async (values: CreateTopicInput) => {
+  const handleSubmit = async (values: CreateTopicInput) => {
+    if (!ensureOnboarded()) return
+
     setSubmitting(true)
     setError(null)
 
@@ -50,26 +50,6 @@ export default function NewTopicPage() {
     }
   }
 
-  const handleSubmit = async (values: CreateTopicInput) => {
-    if (!onboarding.loading && !onboarding.complete) {
-      pendingValues.current = values
-      onboarding.openModal()
-      return
-    }
-    await doSubmit(values)
-  }
-
-  const handleOnboardingComplete = async (
-    responses: Array<{ fieldId: string; response: unknown }>
-  ) => {
-    const success = await onboarding.submit(responses)
-    if (success && pendingValues.current) {
-      await doSubmit(pendingValues.current)
-      pendingValues.current = null
-    }
-    return success
-  }
-
   return (
     <ForumLayout communityName={communityName}>
       <div className="space-y-6">
@@ -91,16 +71,6 @@ export default function NewTopicPage() {
           submitting={submitting}
           initialValues={{ category: initialCategory }}
         />
-
-        <OnboardingModal
-          open={onboarding.showModal}
-          fields={onboarding.status?.fields ?? []}
-          onSubmit={handleOnboardingComplete}
-          onCancel={() => {
-            onboarding.closeModal()
-            pendingValues.current = null
-          }}
-        />
       </div>
     </ForumLayout>
   )
diff --git a/src/components/like-button.test.tsx b/src/components/like-button.test.tsx
index caefc12..57218da 100644
--- a/src/components/like-button.test.tsx
+++ b/src/components/like-button.test.tsx
@@ -8,6 +8,8 @@ import { render, screen, waitFor } from '@testing-library/react'
 import userEvent from '@testing-library/user-event'
 import { axe } from 'vitest-axe'
 import { LikeButton } from './like-button'
+import { createMockOnboardingContext } from '@/test/mock-onboarding'
+import type { OnboardingContextValue } from '@/context/onboarding-context'
 
 // --- Mocks ---
 
@@ -35,6 +37,12 @@ vi.mock('@/hooks/use-auth', () => ({
   }),
 }))
 
+let mockOnboardingContext: OnboardingContextValue = createMockOnboardingContext()
+
+vi.mock('@/context/onboarding-context', () => ({
+  useOnboardingContext: () => mockOnboardingContext,
+}))
+
 vi.mock('@/lib/api/client', () => ({
   getReactions: vi.fn().mockResolvedValue({ reactions: [], cursor: null }),
   createReaction: vi.fn().mockResolvedValue({
@@ -62,6 +70,7 @@ beforeEach(() => {
   mockToast.mockReset()
   mockGetAccessToken.mockReturnValue('mock-access-token')
   mockAuthFetch.mockReset()
+  mockOnboardingContext = createMockOnboardingContext()
   vi.mocked(getReactions).mockResolvedValue({ reactions: [], cursor: null })
   vi.mocked(createReaction).mockResolvedValue({
     uri: 'at://did:plc:user-test-001/forum.barazo.interaction.reaction/abc123',
@@ -355,6 +364,43 @@ describe('LikeButton', () => {
     })
   })
 
+  describe('onboarding gate', () => {
+    it('does not call createReaction when ensureOnboarded returns false', async () => {
+      mockOnboardingContext = createMockOnboardingContext({
+        ensureOnboarded: vi.fn(() => false),
+      })
+
+      const user = userEvent.setup()
+      render(<LikeButton {...defaultProps} />)
+
+      await waitFor(() => {
+        expect(getReactions).toHaveBeenCalled()
+      })
+
+      await user.click(screen.getByRole('button'))
+
+      expect(createReaction).not.toHaveBeenCalled()
+      expect(deleteReaction).not.toHaveBeenCalled()
+    })
+
+    it('proceeds normally when ensureOnboarded returns true', async () => {
+      mockOnboardingContext = createMockOnboardingContext({
+        ensureOnboarded: vi.fn(() => true),
+      })
+
+      const user = userEvent.setup()
+      render(<LikeButton {...defaultProps} />)
+
+      await waitFor(() => {
+        expect(getReactions).toHaveBeenCalled()
+      })
+
+      await user.click(screen.getByRole('button'))
+
+      expect(createReaction).toHaveBeenCalled()
+    })
+  })
+
   describe('size variants', () => {
     it('renders with default size', () => {
       render(<LikeButton {...defaultProps} />)
diff --git a/src/components/like-button.tsx b/src/components/like-button.tsx
index 56b7b45..93a8ac7 100644
--- a/src/components/like-button.tsx
+++ b/src/components/like-button.tsx
@@ -9,6 +9,7 @@
 import { useState, useEffect, useCallback, useRef } from 'react'
 import { Heart } from '@phosphor-icons/react'
 import { useAuth } from '@/hooks/use-auth'
+import { useOnboardingContext } from '@/context/onboarding-context'
 import { useToast } from '@/hooks/use-toast'
 import { getReactions, createReaction, deleteReaction } from '@/lib/api/client'
 import { cn } from '@/lib/utils'
@@ -30,6 +31,7 @@ export function LikeButton({
   className,
 }: LikeButtonProps) {
   const { user, isAuthenticated, getAccessToken } = useAuth()
+  const { ensureOnboarded } = useOnboardingContext()
   const { toast } = useToast()
   const [liked, setLiked] = useState(false)
   const [count, setCount] = useState(initialCount)
@@ -73,6 +75,7 @@ export function LikeButton({
   }, [subjectUri, isAuthenticated, user, getAccessToken])
 
   const handleToggle = useCallback(async () => {
+    if (!ensureOnboarded()) return
     const token = getAccessToken()
     if (!token || pending) return
 
@@ -109,7 +112,7 @@ export function LikeButton({
     } finally {
       setPending(false)
     }
-  }, [liked, count, pending, subjectUri, subjectCid, getAccessToken, toast])
+  }, [liked, count, pending, subjectUri, subjectCid, getAccessToken, ensureOnboarded, toast])
 
   const iconSize = size === 'sm' ? 'h-3.5 w-3.5' : 'h-4 w-4'
 
diff --git a/src/components/reply-composer.test.tsx b/src/components/reply-composer.test.tsx
index 6c3bb76..6f479ea 100644
--- a/src/components/reply-composer.test.tsx
+++ b/src/components/reply-composer.test.tsx
@@ -8,6 +8,8 @@ import userEvent from '@testing-library/user-event'
 import { axe } from 'vitest-axe'
 import { ReplyComposer } from './reply-composer'
 import type { ReplyTarget } from './reply-composer'
+import { createMockOnboardingContext } from '@/test/mock-onboarding'
+import type { OnboardingContextValue } from '@/context/onboarding-context'
 
 const mockGetAccessToken = vi.fn<() => string | null>(() => 'mock-access-token')
 const mockToast = vi.fn()
@@ -43,6 +45,12 @@ vi.mock('@/lib/api/client', () => ({
   createReply: (...args: unknown[]) => mockCreateReply(...args),
 }))
 
+let mockOnboardingContext: OnboardingContextValue = createMockOnboardingContext()
+
+vi.mock('@/context/onboarding-context', () => ({
+  useOnboardingContext: () => mockOnboardingContext,
+}))
+
 const defaultProps = {
   topicUri: 'at://did:plc:abc/forum.barazo.topic/123',
   topicCid: 'bafyreiabc123',
@@ -59,6 +67,7 @@ const mockReplyTarget: ReplyTarget = {
 
 beforeEach(() => {
   vi.clearAllMocks()
+  mockOnboardingContext = createMockOnboardingContext()
   mockCreateReply.mockResolvedValue({
     uri: 'at://did:plc:user-test-001/forum.barazo.reply/789',
     cid: 'bafyrei789',
@@ -328,6 +337,59 @@ describe('ReplyComposer', () => {
     })
   })
 
+  describe('onboarding gate', () => {
+    it('does not call createReply when ensureOnboarded returns false', async () => {
+      mockOnboardingContext = createMockOnboardingContext({
+        ensureOnboarded: vi.fn(() => false),
+      })
+
+      const user = userEvent.setup()
+      render(<ReplyComposer {...defaultProps} />)
+
+      await user.click(screen.getByText('Write a reply...'))
+      const textarea = screen.getByRole('textbox', { name: 'Reply' })
+      await user.type(textarea, 'My test reply')
+      await user.click(screen.getByRole('button', { name: 'Reply' }))
+
+      expect(mockCreateReply).not.toHaveBeenCalled()
+    })
+
+    it('preserves content when ensureOnboarded returns false', async () => {
+      mockOnboardingContext = createMockOnboardingContext({
+        ensureOnboarded: vi.fn(() => false),
+      })
+
+      const user = userEvent.setup()
+      render(<ReplyComposer {...defaultProps} />)
+
+      await user.click(screen.getByText('Write a reply...'))
+      const textarea = screen.getByRole('textbox', { name: 'Reply' })
+      await user.type(textarea, 'My test reply')
+      await user.click(screen.getByRole('button', { name: 'Reply' }))
+
+      // Content should still be there
+      expect(screen.getByRole('textbox', { name: 'Reply' })).toHaveValue('My test reply')
+    })
+
+    it('proceeds normally when ensureOnboarded returns true', async () => {
+      mockOnboardingContext = createMockOnboardingContext({
+        ensureOnboarded: vi.fn(() => true),
+      })
+
+      const user = userEvent.setup()
+      render(<ReplyComposer {...defaultProps} />)
+
+      await user.click(screen.getByText('Write a reply...'))
+      const textarea = screen.getByRole('textbox', { name: 'Reply' })
+      await user.type(textarea, 'My test reply')
+      await user.click(screen.getByRole('button', { name: 'Reply' }))
+
+      await waitFor(() => {
+        expect(mockCreateReply).toHaveBeenCalled()
+      })
+    })
+  })
+
   describe('initialContent', () => {
     it('populates textarea with initialContent and auto-expands', () => {
       const initialText = '> quoted text\n\n'
diff --git a/src/components/reply-composer.tsx b/src/components/reply-composer.tsx
index ceda3db..0535e1e 100644
--- a/src/components/reply-composer.tsx
+++ b/src/components/reply-composer.tsx
@@ -9,6 +9,7 @@
 import { useState, useCallback, useRef, useEffect, useImperativeHandle, forwardRef } from 'react'
 import { PaperPlaneRight, X, Lock } from '@phosphor-icons/react'
 import { useAuth } from '@/hooks/use-auth'
+import { useOnboardingContext } from '@/context/onboarding-context'
 import { useToast } from '@/hooks/use-toast'
 import { createReply } from '@/lib/api/client'
 import { MarkdownEditor } from '@/components/markdown-editor'
@@ -53,6 +54,7 @@ export const ReplyComposer = forwardRef<ReplyComposerHandle, ReplyComposerProps>
     ref
   ) {
     const { getAccessToken } = useAuth()
+    const { ensureOnboarded } = useOnboardingContext()
     const { toast } = useToast()
     const [isExpanded, setIsExpanded] = useState(false)
     const [content, setContent] = useState(initialContent)
@@ -124,6 +126,7 @@ export const ReplyComposer = forwardRef<ReplyComposerHandle, ReplyComposerProps>
     }, [])
 
     const handleSubmit = useCallback(async () => {
+      if (!ensureOnboarded()) return
       const trimmed = content.trim()
       if (!trimmed) return
 
@@ -148,7 +151,7 @@ export const ReplyComposer = forwardRef<ReplyComposerHandle, ReplyComposerProps>
       } finally {
         setSubmitting(false)
       }
-    }, [content, topicUri, replyTarget, getAccessToken, onReplyCreated, toast])
+    }, [content, topicUri, replyTarget, getAccessToken, ensureOnboarded, onReplyCreated, toast])
 
     if (isLocked) {
       return (
diff --git a/src/components/topic-detail-client.test.tsx b/src/components/topic-detail-client.test.tsx
index 2766f28..c02d3c5 100644
--- a/src/components/topic-detail-client.test.tsx
+++ b/src/components/topic-detail-client.test.tsx
@@ -8,6 +8,11 @@ import userEvent from '@testing-library/user-event'
 import { axe } from 'vitest-axe'
 import { TopicDetailClient } from './topic-detail-client'
 import { mockTopics, mockReplies } from '@/mocks/data'
+import { createMockOnboardingContext } from '@/test/mock-onboarding'
+
+vi.mock('@/context/onboarding-context', () => ({
+  useOnboardingContext: () => createMockOnboardingContext(),
+}))
 
 const mockRouterRefresh = vi.fn()
 
diff --git a/src/context/onboarding-context.test.tsx b/src/context/onboarding-context.test.tsx
new file mode 100644
index 0000000..02dfe87
--- /dev/null
+++ b/src/context/onboarding-context.test.tsx
@@ -0,0 +1,370 @@
+/**
+ * Tests for OnboardingProvider context.
+ * Validates onboarding status fetching, ensureOnboarded gate logic,
+ * modal rendering, and submission flow.
+ */
+
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { render, screen, waitFor, act } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { OnboardingProvider, useOnboardingContext } from './onboarding-context'
+
+// --- Mocks ---
+
+const mockGetAccessToken = vi.fn<() => string | null>(() => 'mock-access-token')
+let mockIsAuthenticated = true
+let mockAuthLoading = false
+
+vi.mock('@/hooks/use-auth', () => ({
+  useAuth: () => ({
+    user: mockIsAuthenticated ? { did: 'did:plc:user-test-001', handle: 'test.bsky.social' } : null,
+    isAuthenticated: mockIsAuthenticated,
+    isLoading: mockAuthLoading,
+    getAccessToken: mockGetAccessToken,
+    login: vi.fn(),
+    logout: vi.fn(),
+    setSessionFromCallback: vi.fn(),
+    authFetch: vi.fn(),
+    crossPostScopesGranted: false,
+    requestCrossPostAuth: vi.fn(),
+  }),
+}))
+
+const mockGetOnboardingStatus = vi.fn()
+const mockSubmitOnboarding = vi.fn()
+
+vi.mock('@/lib/api/client', () => ({
+  getOnboardingStatus: (...args: unknown[]) => mockGetOnboardingStatus(...args),
+  submitOnboarding: (...args: unknown[]) => mockSubmitOnboarding(...args),
+}))
+
+const completeStatus = {
+  complete: true,
+  fields: [],
+  responses: {},
+  missingFields: [],
+}
+
+const incompleteStatus = {
+  complete: false,
+  fields: [
+    {
+      id: 'age-field',
+      communityDid: 'did:plc:community-001',
+      fieldType: 'age_confirmation',
+      label: 'Confirm your age',
+      description: null,
+      isMandatory: true,
+      sortOrder: 0,
+      config: null,
+      createdAt: '2026-01-01T00:00:00.000Z',
+      updatedAt: '2026-01-01T00:00:00.000Z',
+    },
+  ],
+  responses: {},
+  missingFields: [{ id: 'age-field', label: 'Confirm your age', fieldType: 'age_confirmation' }],
+}
+
+beforeEach(() => {
+  vi.clearAllMocks()
+  mockIsAuthenticated = true
+  mockAuthLoading = false
+  mockGetAccessToken.mockReturnValue('mock-access-token')
+  mockGetOnboardingStatus.mockResolvedValue(completeStatus)
+  mockSubmitOnboarding.mockResolvedValue({ success: true })
+})
+
+/** Test consumer that exposes context values */
+function TestConsumer() {
+  const ctx = useOnboardingContext()
+  return (
+    <div>
+      <span data-testid="loading">{String(ctx.loading)}</span>
+      <span data-testid="complete">{String(ctx.complete)}</span>
+      <span data-testid="showModal">{String(ctx.showModal)}</span>
+      <button type="button" onClick={() => ctx.ensureOnboarded()} data-testid="ensure-btn">
+        Ensure
+      </button>
+      <button
+        type="button"
+        onClick={() => void ctx.submit([{ fieldId: 'age-field', response: true }])}
+        data-testid="submit-btn"
+      >
+        Submit
+      </button>
+    </div>
+  )
+}
+
+function renderWithProvider() {
+  return render(
+    <OnboardingProvider>
+      <TestConsumer />
+    </OnboardingProvider>
+  )
+}
+
+describe('OnboardingProvider', () => {
+  describe('rendering', () => {
+    it('renders children', () => {
+      render(
+        <OnboardingProvider>
+          <span>child content</span>
+        </OnboardingProvider>
+      )
+      expect(screen.getByText('child content')).toBeInTheDocument()
+    })
+  })
+
+  describe('fetching status', () => {
+    it('fetches onboarding status when authenticated', async () => {
+      renderWithProvider()
+
+      await waitFor(() => {
+        expect(mockGetOnboardingStatus).toHaveBeenCalledWith('mock-access-token')
+      })
+    })
+
+    it('does not fetch status when unauthenticated', async () => {
+      mockIsAuthenticated = false
+      mockGetAccessToken.mockReturnValue(null)
+
+      renderWithProvider()
+
+      await act(async () => {
+        await new Promise((r) => setTimeout(r, 50))
+      })
+
+      expect(mockGetOnboardingStatus).not.toHaveBeenCalled()
+    })
+
+    it('does not fetch status while auth is loading', async () => {
+      mockAuthLoading = true
+
+      renderWithProvider()
+
+      await act(async () => {
+        await new Promise((r) => setTimeout(r, 50))
+      })
+
+      expect(mockGetOnboardingStatus).not.toHaveBeenCalled()
+    })
+
+    it('sets complete to true when status.complete is true', async () => {
+      mockGetOnboardingStatus.mockResolvedValue(completeStatus)
+
+      renderWithProvider()
+
+      await waitFor(() => {
+        expect(screen.getByTestId('complete')).toHaveTextContent('true')
+      })
+    })
+
+    it('sets complete to false when status.complete is false', async () => {
+      mockGetOnboardingStatus.mockResolvedValue(incompleteStatus)
+
+      renderWithProvider()
+
+      await waitFor(() => {
+        expect(screen.getByTestId('complete')).toHaveTextContent('false')
+      })
+    })
+
+    it('sets loading to false after fetch completes', async () => {
+      renderWithProvider()
+
+      await waitFor(() => {
+        expect(screen.getByTestId('loading')).toHaveTextContent('false')
+      })
+    })
+  })
+
+  describe('ensureOnboarded', () => {
+    it('returns true when onboarding is complete', async () => {
+      mockGetOnboardingStatus.mockResolvedValue(completeStatus)
+
+      let result: boolean | undefined
+      function Consumer() {
+        const ctx = useOnboardingContext()
+        return (
+          <button
+            type="button"
+            onClick={() => {
+              result = ctx.ensureOnboarded()
+            }}
+          >
+            Check
+          </button>
+        )
+      }
+
+      render(
+        <OnboardingProvider>
+          <Consumer />
+        </OnboardingProvider>
+      )
+
+      await waitFor(() => {
+        expect(mockGetOnboardingStatus).toHaveBeenCalled()
+      })
+
+      const user = userEvent.setup()
+      await user.click(screen.getByRole('button', { name: 'Check' }))
+
+      expect(result).toBe(true)
+    })
+
+    it('returns true when loading (fail-open)', async () => {
+      mockGetOnboardingStatus.mockImplementation(() => new Promise(() => {}))
+
+      let result: boolean | undefined
+      function Consumer() {
+        const ctx = useOnboardingContext()
+        return (
+          <button
+            type="button"
+            onClick={() => {
+              result = ctx.ensureOnboarded()
+            }}
+          >
+            Check
+          </button>
+        )
+      }
+
+      render(
+        <OnboardingProvider>
+          <Consumer />
+        </OnboardingProvider>
+      )
+
+      const user = userEvent.setup()
+      await user.click(screen.getByRole('button', { name: 'Check' }))
+
+      expect(result).toBe(true)
+    })
+
+    it('returns true when unauthenticated (fail-open)', async () => {
+      mockIsAuthenticated = false
+      mockGetAccessToken.mockReturnValue(null)
+
+      let result: boolean | undefined
+      function Consumer() {
+        const ctx = useOnboardingContext()
+        return (
+          <button
+            type="button"
+            onClick={() => {
+              result = ctx.ensureOnboarded()
+            }}
+          >
+            Check
+          </button>
+        )
+      }
+
+      render(
+        <OnboardingProvider>
+          <Consumer />
+        </OnboardingProvider>
+      )
+
+      const user = userEvent.setup()
+      await user.click(screen.getByRole('button', { name: 'Check' }))
+
+      expect(result).toBe(true)
+    })
+
+    it('returns false and opens modal when incomplete', async () => {
+      mockGetOnboardingStatus.mockResolvedValue(incompleteStatus)
+
+      let result: boolean | undefined
+      function Consumer() {
+        const ctx = useOnboardingContext()
+        return (
+          <>
+            <span data-testid="modal-state">{String(ctx.showModal)}</span>
+            <button
+              type="button"
+              onClick={() => {
+                result = ctx.ensureOnboarded()
+              }}
+            >
+              Check
+            </button>
+          </>
+        )
+      }
+
+      render(
+        <OnboardingProvider>
+          <Consumer />
+        </OnboardingProvider>
+      )
+
+      await waitFor(() => {
+        expect(mockGetOnboardingStatus).toHaveBeenCalled()
+      })
+
+      await act(async () => {
+        await new Promise((r) => setTimeout(r, 10))
+      })
+
+      const user = userEvent.setup()
+      await user.click(screen.getByRole('button', { name: 'Check' }))
+
+      expect(result).toBe(false)
+      expect(screen.getByTestId('modal-state')).toHaveTextContent('true')
+    })
+  })
+
+  describe('submit', () => {
+    it('calls API, refreshes status, and closes modal on success', async () => {
+      mockGetOnboardingStatus
+        .mockResolvedValueOnce(incompleteStatus)
+        .mockResolvedValueOnce(completeStatus)
+
+      renderWithProvider()
+
+      await waitFor(() => {
+        expect(screen.getByTestId('complete')).toHaveTextContent('false')
+      })
+
+      const user = userEvent.setup()
+      await user.click(screen.getByTestId('ensure-btn'))
+
+      expect(screen.getByTestId('showModal')).toHaveTextContent('true')
+
+      await user.click(screen.getByTestId('submit-btn'))
+
+      await waitFor(() => {
+        expect(mockSubmitOnboarding).toHaveBeenCalledWith(
+          { responses: [{ fieldId: 'age-field', response: true }] },
+          'mock-access-token'
+        )
+      })
+
+      await waitFor(() => {
+        expect(screen.getByTestId('complete')).toHaveTextContent('true')
+        expect(screen.getByTestId('showModal')).toHaveTextContent('false')
+      })
+    })
+  })
+
+  describe('useOnboardingContext outside provider', () => {
+    it('throws when used outside OnboardingProvider', () => {
+      const consoleSpy = vi.spyOn(console, 'error').mockImplementation(() => {})
+
+      function BadConsumer() {
+        useOnboardingContext()
+        return null
+      }
+
+      expect(() => render(<BadConsumer />)).toThrow(
+        'useOnboardingContext must be used within an OnboardingProvider'
+      )
+
+      consoleSpy.mockRestore()
+    })
+  })
+})
diff --git a/src/context/onboarding-context.tsx b/src/context/onboarding-context.tsx
new file mode 100644
index 0000000..3eb7ce8
--- /dev/null
+++ b/src/context/onboarding-context.tsx
@@ -0,0 +1,144 @@
+/**
+ * Global onboarding context provider.
+ * Fetches onboarding status on mount (when authenticated) and provides
+ * ensureOnboarded() for any write action to gate behind onboarding completion.
+ * Renders the OnboardingModal globally so individual pages don't need to.
+ * @see specs/prd-web.md Section M5 (Onboarding)
+ */
+
+'use client'
+
+import { createContext, useCallback, useContext, useEffect, useMemo, useState } from 'react'
+import type { ReactNode } from 'react'
+import type { OnboardingStatus } from '@/lib/api/types'
+import { getOnboardingStatus, submitOnboarding } from '@/lib/api/client'
+import { useAuth } from '@/hooks/use-auth'
+import { OnboardingModal } from '@/components/onboarding-modal'
+
+export interface OnboardingContextValue {
+  /** Whether onboarding status is still loading */
+  loading: boolean
+  /** Whether onboarding is complete (false when status is null/loading) */
+  complete: boolean
+  /** Whether the onboarding modal is currently shown */
+  showModal: boolean
+  /** Full onboarding status from the API */
+  status: OnboardingStatus | null
+  /**
+   * Gate function for write actions. Returns true if the user may proceed.
+   * Fail-open: returns true when loading, unauthenticated, or status is null.
+   * Returns false and opens the modal when onboarding is incomplete.
+   */
+  ensureOnboarded: () => boolean
+  /** Submit onboarding responses, refresh status, close modal on success */
+  submit: (responses: Array<{ fieldId: string; response: unknown }>) => Promise<boolean>
+  /** Close the onboarding modal */
+  closeModal: () => void
+}
+
+const OnboardingContext = createContext<OnboardingContextValue | null>(null)
+
+interface OnboardingProviderProps {
+  children: ReactNode
+}
+
+export function OnboardingProvider({ children }: OnboardingProviderProps) {
+  const { isAuthenticated, isLoading: authLoading, getAccessToken } = useAuth()
+  const [loading, setLoading] = useState(true)
+  const [status, setStatus] = useState<OnboardingStatus | null>(null)
+  const [showModal, setShowModal] = useState(false)
+
+  const fetchStatus = useCallback(async () => {
+    const token = getAccessToken()
+    if (!token) {
+      setLoading(false)
+      return
+    }
+
+    try {
+      const result = await getOnboardingStatus(token)
+      setStatus(result)
+    } catch {
+      setStatus(null)
+    } finally {
+      setLoading(false)
+    }
+  }, [getAccessToken])
+
+  useEffect(() => {
+    if (!isAuthenticated || authLoading) {
+      setLoading(false)
+      return
+    }
+    void fetchStatus()
+  }, [isAuthenticated, authLoading, fetchStatus])
+
+  const ensureOnboarded = useCallback((): boolean => {
+    // Fail-open: allow action when loading, unauthenticated, or status unknown
+    if (loading || !isAuthenticated || status === null) {
+      return true
+    }
+
+    if (status.complete) {
+      return true
+    }
+
+    // Onboarding incomplete -- open modal
+    setShowModal(true)
+    return false
+  }, [loading, isAuthenticated, status])
+
+  const submit = useCallback(
+    async (responses: Array<{ fieldId: string; response: unknown }>): Promise<boolean> => {
+      const token = getAccessToken()
+      if (!token) return false
+
+      try {
+        await submitOnboarding({ responses }, token)
+        await fetchStatus()
+        setShowModal(false)
+        return true
+      } catch {
+        return false
+      }
+    },
+    [fetchStatus, getAccessToken]
+  )
+
+  const closeModal = useCallback(() => {
+    setShowModal(false)
+  }, [])
+
+  const value = useMemo<OnboardingContextValue>(
+    () => ({
+      loading,
+      complete: status?.complete ?? false,
+      showModal,
+      status,
+      ensureOnboarded,
+      submit,
+      closeModal,
+    }),
+    [loading, showModal, status, ensureOnboarded, submit, closeModal]
+  )
+
+  return (
+    <OnboardingContext.Provider value={value}>
+      {children}
+      <OnboardingModal
+        open={showModal}
+        fields={status?.fields ?? []}
+        onSubmit={submit}
+        onCancel={closeModal}
+      />
+    </OnboardingContext.Provider>
+  )
+}
+
+export function useOnboardingContext(): OnboardingContextValue {
+  const context = useContext(OnboardingContext)
+  if (!context) {
+    throw new Error('useOnboardingContext must be used within an OnboardingProvider')
+  }
+  return context
+}
diff --git a/src/test/mock-onboarding.tsx b/src/test/mock-onboarding.tsx
new file mode 100644
index 0000000..c44bbd7
--- /dev/null
+++ b/src/test/mock-onboarding.tsx
@@ -0,0 +1,63 @@
+/**
+ * Shared test utility for mocking onboarding context.
+ * Use createMockOnboardingContext() to get default overrides for tests
+ * that render components gated by onboarding.
+ */
+
+import { vi } from 'vitest'
+import type { OnboardingContextValue } from '@/context/onboarding-context'
+
+export function createMockOnboardingContext(
+  overrides: Partial<OnboardingContextValue> = {}
+): OnboardingContextValue {
+  return {
+    loading: false,
+    complete: true,
+    showModal: false,
+    status: {
+      complete: true,
+      fields: [],
+      responses: {},
+      missingFields: [],
+    },
+    ensureOnboarded: vi.fn(() => true),
+    submit: vi.fn().mockResolvedValue(true),
+    closeModal: vi.fn(),
+    ...overrides,
+  }
+}
+
+export function createIncompleteOnboardingContext(
+  overrides: Partial<OnboardingContextValue> = {}
+): OnboardingContextValue {
+  return {
+    loading: false,
+    complete: false,
+    showModal: false,
+    status: {
+      complete: false,
+      fields: [
+        {
+          id: 'age-field',
+          communityDid: 'did:plc:community-001',
+          fieldType: 'age_confirmation',
+          label: 'Confirm your age',
+          description: null,
+          isMandatory: true,
+          sortOrder: 0,
+          config: null,
+          createdAt: '2026-01-01T00:00:00.000Z',
+          updatedAt: '2026-01-01T00:00:00.000Z',
+        },
+      ],
+      responses: {},
+      missingFields: [
+        { id: 'age-field', label: 'Confirm your age', fieldType: 'age_confirmation' },
+      ],
+    },
+    ensureOnboarded: vi.fn(() => false),
+    submit: vi.fn().mockResolvedValue(true),
+    closeModal: vi.fn(),
+    ...overrides,
+  }
+}