From f12186b069e0169b4aca4897c61a4b5f5927ce66 Mon Sep 17 00:00:00 2001
From: Claude <noreply@anthropic.com>
Date: Tue, 23 Jun 2026 17:41:56 +0000
Subject: [PATCH] fix(ci): scope nightly type-drift typecheck to the package
 under test

Vitest's `--typecheck` engine built its tsc program from the root
`tsconfig.json`, which has no `include` and therefore swept the entire
monorepo's source. Example UI `.tsx` files (which need `jsx`) and provider
packages relying on their own ambient `types`/`lib` (Chrome AI, Cloudflare)
then surfaced hundreds of "unhandled source errors" unrelated to the drift
guard, failing the nightly even though the 3 drift tests passed.

Point vitest's typecheck at a dedicated `tsconfig.typecheck.json` scoped to
`packages/ai/src`, so the program only contains the file under test and
resolves cross-package imports to the already-built `.d.ts` declarations.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G6ie5uJvfMpFZrGtrKL1c4
---
 tsconfig.typecheck.json | 10 ++++++++++
 vitest.config.ts        |  7 +++++++
 2 files changed, 17 insertions(+)
 create mode 100644 tsconfig.typecheck.json

diff --git a/tsconfig.typecheck.json b/tsconfig.typecheck.json
new file mode 100644
index 000000000..f28873ee4
--- /dev/null
+++ b/tsconfig.typecheck.json
@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "composite": false,
+    "incremental": false,
+    "noEmit": true
+  },
+  "include": ["packages/ai/src/**/*"],
+  "exclude": ["**/dist", "**/node_modules"]
+}
diff --git a/vitest.config.ts b/vitest.config.ts
index 008db3b2a..3b9a33e4d 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -8,6 +8,13 @@ export default defineConfig({
   envDir: __dirname,
   test: {
     setupFiles: ["./vitest.setup.ts"],
+    // The nightly type-drift guard runs `.test-d.ts` files through vitest's
+    // `--typecheck` engine. Scope the tsc program to the package under test so
+    // unrelated source (example UIs needing `jsx`, providers relying on their
+    // own ambient `types`/`lib`) is not swept in and reported as drift.
+    typecheck: {
+      tsconfig: "./tsconfig.typecheck.json",
+    },
     testTimeout: 15000, // 15 second global timeout (WASM Postgres / PGlite init can be slow)
     // Vitest uses hookTimeout for beforeEach/afterAll separately from testTimeout; keep both aligned
     hookTimeout: 15000,