diff --git a/.github/workflows/api-e2e.yml b/.github/workflows/api-e2e.yml
index 5f074555..fd5cea76 100644
--- a/.github/workflows/api-e2e.yml
+++ b/.github/workflows/api-e2e.yml
@@ -23,6 +23,7 @@ env:
   PGLITE: true
   DATABASE_URL: postgresql://localhost/test
   JWT_SECRET: e2e-jwt-secret-min-32-chars-for-tests
+  AI_PROVIDER: anthropic
   ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
 
 jobs:
@@ -53,6 +54,16 @@ jobs:
         run: pnpm turbo run test --filter=@repo/api
       - name: Install Playwright
         run: pnpm --filter @repo/api exec playwright install chromium --with-deps
+      - name: Verify ANTHROPIC_API_KEY for E2E (AI_PROVIDER=anthropic)
+        shell: bash
+        env:
+          AI_PROVIDER: ${{ env.AI_PROVIDER }}
+          ANTHROPIC_API_KEY: ${{ env.ANTHROPIC_API_KEY }}
+        run: |
+          if [[ "${AI_PROVIDER}" == "anthropic" && -z "${ANTHROPIC_API_KEY}" ]]; then
+            echo "::error::AI_PROVIDER is anthropic but ANTHROPIC_API_KEY is empty or unset. Set the ANTHROPIC_API_KEY repository secret; required before E2E tests (local)." >&2
+            exit 1
+          fi
       - name: E2E tests (local)
         run: pnpm --filter @repo/api test:e2e:local
       - name: Upload Playwright report
diff --git a/.github/workflows/web-e2e.yml b/.github/workflows/web-e2e.yml
index e0a64982..42428d34 100644
--- a/.github/workflows/web-e2e.yml
+++ b/.github/workflows/web-e2e.yml
@@ -27,6 +27,7 @@ env:
   DATABASE_URL: postgresql://localhost/test
   JWT_SECRET: e2e-jwt-secret-min-32-chars-for-tests
   NEXT_PUBLIC_API_URL: http://localhost:3001
+  AI_PROVIDER: anthropic
   ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
 
 jobs:
@@ -57,6 +58,16 @@ jobs:
         run: pnpm turbo run test --filter=@repo/web
       - name: Install Playwright
         run: pnpm --filter @repo/web exec playwright install chromium --with-deps
+      - name: Verify ANTHROPIC_API_KEY for E2E (AI_PROVIDER=anthropic)
+        shell: bash
+        env:
+          AI_PROVIDER: ${{ env.AI_PROVIDER }}
+          ANTHROPIC_API_KEY: ${{ env.ANTHROPIC_API_KEY }}
+        run: |
+          if [[ "${AI_PROVIDER}" == "anthropic" && -z "${ANTHROPIC_API_KEY}" ]]; then
+            echo "::error::AI_PROVIDER is anthropic but ANTHROPIC_API_KEY is empty or unset. Set the ANTHROPIC_API_KEY repository secret; required before E2E tests (local)." >&2
+            exit 1
+          fi
       - name: E2E tests (local)
         env:
           SKIP_BUILD: '1'
diff --git a/apps/api/.env.test.example b/apps/api/.env.test.example
index 5372e24d..4dcf7937 100644
--- a/apps/api/.env.test.example
+++ b/apps/api/.env.test.example
@@ -28,6 +28,7 @@ DATABASE_URL=postgresql://localhost/test
 # AI
 # -----------------------------------------------------------------------------
 ANTHROPIC_API_KEY=sk-ant-xxx
+AI_PROVIDER=anthropic
 # OPEN_ROUTER_API_KEY=
 # OLLAMA_BASE_URL=http://localhost:11434
 # AI_DEFAULT_MODEL=claude-sonnet-4-20250514
diff --git a/apps/api/scripts/run-e2e-local.mjs b/apps/api/scripts/run-e2e-local.mjs
index 63486a2b..84c71e74 100644
--- a/apps/api/scripts/run-e2e-local.mjs
+++ b/apps/api/scripts/run-e2e-local.mjs
@@ -2,6 +2,7 @@
 /**
  * E2E local: spawn Fastify API, poll until healthy, run Playwright, cleanup on exit.
  * No wait-on. Uses ALLOW_TEST, PGLITE, NODE_ENV=test.
+ * Forces AI_PROVIDER=anthropic and strips Open Router/Ollama/AI_DEFAULT_MODEL (parity with Vitest + web E2E).
  */
 import { spawn, spawnSync } from 'node:child_process'
 import { existsSync, readFileSync } from 'node:fs'
@@ -67,6 +68,13 @@ async function main() {
     )
     process.exit(1)
   }
+  const anthropicApiKey = loaded.ANTHROPIC_API_KEY ?? process.env.ANTHROPIC_API_KEY
+  if (!anthropicApiKey) {
+    process.stderr.write(
+      'E2E local: ANTHROPIC_API_KEY must be set in .env.test or process.env when AI_PROVIDER is anthropic. Refusing to run without it.\n',
+    )
+    process.exit(1)
+  }
   const env = {
     ...process.env,
     ...loaded,
@@ -74,7 +82,12 @@ async function main() {
     PGLITE: 'true',
     NODE_ENV: 'test',
     JWT_SECRET: jwtSecret,
+    AI_PROVIDER: 'anthropic',
+    ANTHROPIC_API_KEY: anthropicApiKey,
   }
+  delete env.OPEN_ROUTER_API_KEY
+  delete env.OLLAMA_BASE_URL
+  delete env.AI_DEFAULT_MODEL
 
   const fastify = spawn(process.execPath, ['--import', 'tsx', 'server.ts'], {
     cwd: fastifyDir,
diff --git a/apps/docu/content/docs/testing/frontend-testing.mdx b/apps/docu/content/docs/testing/frontend-testing.mdx
index 4732ddd3..2c6cbfb8 100644
--- a/apps/docu/content/docs/testing/frontend-testing.mdx
+++ b/apps/docu/content/docs/testing/frontend-testing.mdx
@@ -58,7 +58,7 @@ test.describe('Magic Link Auth E2E', () => {
 
 - **workers: 1** — Required for PGlite (Fastify test DB) to avoid concurrent writer issues
 - **Test order** — Auth project first (magic-link-auth: error tests, login/logout; ends with logout). Chromium: unauth badge tests first, then first authed test triggers fixture and confirms session, then remaining authed tests run consecutively
-- **Chat E2E** — Requires `OPEN_ROUTER_API_KEY`; see [E2E Testing](/docs/testing/e2e-testing) for env vars. If UNAUTHORIZED, session/Bearer propagation to Fastify `/ai/chat` needs debugging.
+- **Chat E2E** — Requires `ANTHROPIC_API_KEY` (Anthropic Sonnet); see [E2E Testing](/docs/testing/e2e-testing) for env vars. If UNAUTHORIZED, session/Bearer propagation to Fastify `/ai/chat` needs debugging.
 - **Session model** — One login per worker via `authenticatedStorageState` fixture; cookies/storage saved to `test-results/.auth/user.json` (gitignored); each authed test gets a new context created with that storageState. No per-test login
 - **Login/logout tests** — Import from `@playwright/test`, use `page`; need fresh contexts to verify the flow
 - **Authed feature tests** — Import from `e2e/fixtures`, use `authenticatedPage`; no `loginAsTestUser` in test body. Each test gets a fresh context with saved storageState; navigate to target route (e.g. `goto('/')`) before asserting
diff --git a/apps/web/e2e/chat-assistant.spec.ts b/apps/web/e2e/chat-assistant.spec.ts
index d1b1a207..b4f580bf 100644
--- a/apps/web/e2e/chat-assistant.spec.ts
+++ b/apps/web/e2e/chat-assistant.spec.ts
@@ -32,7 +32,7 @@ test.describe('Chat Assistant', () => {
       if (
         /insufficient_quota|insufficient_credits|quota_exceeded|credits_exceeded/i.test(errorText)
       ) {
-        test.skip(true, 'OpenRouter 402 insufficient credits')
+        test.skip(true, 'AI provider quota/credits (402)')
         return
       }
       if (/invalid x-api-key|authentication_error|invalid.*api.*key|401/i.test(errorText)) {
diff --git a/apps/web/scripts/start-e2e-servers.mjs b/apps/web/scripts/start-e2e-servers.mjs
index 9e795ec6..935da3f2 100644
--- a/apps/web/scripts/start-e2e-servers.mjs
+++ b/apps/web/scripts/start-e2e-servers.mjs
@@ -4,6 +4,7 @@
  * Run in one terminal, then in another: pnpm test:e2e
  *
  * Use when Playwright's webServer spawns processes that get OOM killed (exit 137) on constrained VMs.
+ * Pins AI to Anthropic for API (same as test:e2e:local).
  */
 import { spawn } from 'node:child_process'
 import { dirname } from 'node:path'
@@ -18,7 +19,17 @@ const env = {
   PGLITE: 'true',
   NODE_ENV: 'test',
   NEXT_PUBLIC_API_URL: 'http://localhost:3001',
+  AI_PROVIDER: 'anthropic',
 }
+if (env.AI_PROVIDER === 'anthropic' && !String(env.ANTHROPIC_API_KEY ?? '').trim()) {
+  process.stderr.write(
+    'start-e2e-servers: ANTHROPIC_API_KEY is required when AI_PROVIDER is anthropic. Set it in the environment (e.g. .env.local) before starting E2E servers.\n',
+  )
+  process.exit(1)
+}
+delete env.OPEN_ROUTER_API_KEY
+delete env.OLLAMA_BASE_URL
+delete env.AI_DEFAULT_MODEL
 
 const api = spawn('pnpm', ['--filter', '@repo/api', 'start:ci'], {
   cwd: repoRoot,