diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
new file mode 100644
index 000000000..a3feb2ad7
--- /dev/null
+++ b/.github/workflows/CI.yml
@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: Test (Node ${{ matrix.node-version }}, ${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest] # windows-latest
+        node-version: [24, 26]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: npm
+
+      - run: npm ci
+
+      - name: Build
+        run: npm run build
+
+      - name: Run tests
+        run: npm test
diff --git a/__tests__/mcp-initialize.test.ts b/__tests__/mcp-initialize.test.ts
index 4a57ebae0..23c168ebd 100644
--- a/__tests__/mcp-initialize.test.ts
+++ b/__tests__/mcp-initialize.test.ts
@@ -23,6 +23,7 @@ function spawnServer(cwd: string): ChildProcessWithoutNullStreams {
   return spawn(process.execPath, [BIN, 'serve', '--mcp'], {
     cwd,
     stdio: ['pipe', 'pipe', 'pipe'],
+    env: { ...process.env, CODEGRAPH_NO_RELAUNCH: '1' },
   }) as ChildProcessWithoutNullStreams;
 }
 
@@ -99,9 +100,12 @@ describe('MCP initialize handshake (issue #172)', () => {
     tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codegraph-mcp-init-'));
   });
 
-  afterEach(() => {
-    if (child && !child.killed) {
-      child.kill('SIGKILL');
+  afterEach(async () => {
+    if (child) {
+      if (!child.killed) child.kill('SIGKILL');
+      if (child.exitCode === null) {
+        await new Promise<void>(resolve => child!.once('close', resolve));
+      }
       child = null;
     }
     fs.rmSync(tempDir, { recursive: true, force: true });
diff --git a/__tests__/mcp-roots.test.ts b/__tests__/mcp-roots.test.ts
index 8e1d4520d..36d9174c3 100644
--- a/__tests__/mcp-roots.test.ts
+++ b/__tests__/mcp-roots.test.ts
@@ -29,6 +29,7 @@ function spawnServer(cwd: string): ChildProcessWithoutNullStreams {
   return spawn(process.execPath, [BIN, 'serve', '--mcp', '--no-watch'], {
     cwd,
     stdio: ['pipe', 'pipe', 'pipe'],
+    env: { ...process.env, CODEGRAPH_NO_RELAUNCH: '1' },
   }) as ChildProcessWithoutNullStreams;
 }
 
@@ -84,9 +85,12 @@ describe('MCP project resolution via roots/list (issue #196)', () => {
     projectDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codegraph-mcp-proj-'));
   });
 
-  afterEach(() => {
-    if (child && !child.killed) {
-      child.kill('SIGKILL');
+  afterEach(async () => {
+    if (child) {
+      if (!child.killed) child.kill('SIGKILL');
+      if (child.exitCode === null) {
+        await new Promise<void>(resolve => child!.once('close', resolve));
+      }
       child = null;
     }
     fs.rmSync(cwdDir, { recursive: true, force: true });
diff --git a/package.json b/package.json
index 5455ced92..6ed993986 100644
--- a/package.json
+++ b/package.json
@@ -51,6 +51,6 @@
     "vitest": "^2.1.9"
   },
   "engines": {
-    "node": ">=20.0.0 <25.0.0"
+    "node": ">=20.0.0 <25.0.0 || >=26.0.0"
   }
 }
diff --git a/src/bin/codegraph.ts b/src/bin/codegraph.ts
index 6bc63b3fd..f92267229 100644
--- a/src/bin/codegraph.ts
+++ b/src/bin/codegraph.ts
@@ -61,7 +61,7 @@ const importESM = new Function('specifier', 'return import(specifier)') as
 // who patched V8 themselves or want to test a future fix.
 const nodeVersion = process.versions.node;
 const nodeMajor = parseInt(nodeVersion.split('.')[0] ?? '0', 10);
-if (nodeMajor >= 25) {
+if (nodeMajor === 25) {
   process.stderr.write(buildNode25BlockBanner(nodeVersion) + '\n');
   if (!process.env.CODEGRAPH_ALLOW_UNSAFE_NODE) {
     process.exit(1);
diff --git a/vitest.config.ts b/vitest.config.ts
index 2449a989e..814a07233 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -1,10 +1,23 @@
 import { defineConfig } from 'vitest/config';
 
+const NODE_MAJOR = Number.parseInt(process.versions.node.split('.')[0] ?? '0', 10);
+
+// The V8 turboshaft WASM Zone OOM bug that crashes tree-sitter grammar
+// compilation exists in Node 22–25.x. Node 26+ fixes it; forcing
+// --liftoff-only on Node 26 Windows is empirically tied to a fork-worker
+// teardown crash in tinypool, so only apply the flag where it's needed.
+const NEEDS_LIFTOFF_ONLY = NODE_MAJOR >= 22 && NODE_MAJOR <= 25;
+
 export default defineConfig({
   test: {
     globals: true,
     environment: 'node',
     include: ['__tests__/**/*.test.ts'],
+    poolOptions: {
+      forks: {
+        execArgv: NEEDS_LIFTOFF_ONLY ? ['--liftoff-only'] : [],
+      },
+    },
     coverage: {
       provider: 'v8',
       reporter: ['text', 'json', 'html'],