diff --git a/.github/workflows/e2e-nightly-full-matrix.yml b/.github/workflows/e2e-nightly-full-matrix.yml
index f0fc000c..d2598485 100644
--- a/.github/workflows/e2e-nightly-full-matrix.yml
+++ b/.github/workflows/e2e-nightly-full-matrix.yml
@@ -25,8 +25,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        shard: [1, 2, 3, 4, 5, 6, 7, 8]
-        shards: [8]
+        shard: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
+        shards: [12]
     steps:
       - name: Prepare writable home
         run: mkdir -p "$HOME"
@@ -42,11 +42,15 @@ jobs:
       - name: Install
         run: npm ci
 
+      - name: Build docs for E2E
+        run: npm run docs:build
+
       - name: E2E Tests
         env:
           PW_PROJECTS: firefox,webkit,msedge
           # Keep browser processes isolated; concurrent workers cause broad WebKit timing inflation.
           PW_WORKERS: '1'
+          PHASERFORGE_DOCS_PREBUILT: '1'
         run: npm run test:e2e -- --project=firefox --project=webkit --project=msedge --shard=${{ matrix.shard }}/${{ matrix.shards }} --fail-on-flaky-tests
 
       - name: Record timing telemetry
diff --git a/tests/e2e/docs-list-markers.spec.ts b/tests/e2e/docs-list-markers.spec.ts
index ff708d6c..8f4f11e1 100644
--- a/tests/e2e/docs-list-markers.spec.ts
+++ b/tests/e2e/docs-list-markers.spec.ts
@@ -59,7 +59,7 @@ async function ensureDocsBuild(): Promise<void> {
   const donePath = pathMod.join(osMod.tmpdir(), `${runKey}.docs-build.done`);
   const staleMs = 60_000;
 
-  const hasBuiltDocs = () => fsMod.existsSync(donePath) && fsMod.existsSync(docsDistRoot);
+  const hasBuiltDocs = () => fsMod.existsSync(docsDistRoot) && (fsMod.existsSync(donePath) || process.env.PHASERFORGE_DOCS_PREBUILT === '1');
 
   if (hasBuiltDocs()) return;
 
diff --git a/tests/scripts/repair-harness-e2e-timing.test.ts b/tests/scripts/repair-harness-e2e-timing.test.ts
index 9bbc3b1a..c3ccf6be 100644
--- a/tests/scripts/repair-harness-e2e-timing.test.ts
+++ b/tests/scripts/repair-harness-e2e-timing.test.ts
@@ -54,7 +54,20 @@ describe('repair harness E2E timing diagnostics', () => {
   });
 
   it('runs the Full Matrix with one worker to prevent cross-browser WebKit contention', () => {
-    expect(readFileSync('.github/workflows/e2e-nightly-full-matrix.yml', 'utf8')).toContain("PW_WORKERS: '1'");
+    const workflow = readFileSync('.github/workflows/e2e-nightly-full-matrix.yml', 'utf8');
+    expect(workflow).toContain("PW_WORKERS: '1'");
+    expect(workflow).toContain('shard: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]');
+    expect(workflow).toContain('shards: [12]');
+  });
+
+  it('builds docs before the Full Matrix and marks them prebuilt for the docs E2E', () => {
+    const workflow = readFileSync('.github/workflows/e2e-nightly-full-matrix.yml', 'utf8');
+    const docsBuildIndex = workflow.indexOf('- name: Build docs for E2E');
+    const e2eIndex = workflow.indexOf('- name: E2E Tests');
+
+    expect(docsBuildIndex).toBeGreaterThan(-1);
+    expect(docsBuildIndex).toBeLessThan(e2eIndex);
+    expect(workflow).toContain('PHASERFORGE_DOCS_PREBUILT: \'1\'');
   });
 
   it('reproduces an isolated WebKit shard with one worker', () => {