diff --git a/.claude/rules/testing.md b/.claude/rules/testing.md
index 7ff244aca8..4279d9f243 100644
--- a/.claude/rules/testing.md
+++ b/.claude/rules/testing.md
@@ -3,6 +3,9 @@
 ### Required Setup
 `vitest.config.ts` MUST include `smrtVitestPlugin()` in plugins array. Without it: "No field metadata" errors.
 
+### Timeouts
+Never set `testTimeout` without also setting `hookTimeout` — hooks do NOT inherit it and stay on vitest's 10s default. Symptom: the file fails with "Hook timed out in 10000ms" while every test reports *skipped*. Budget for where the work happens: setup that spawns processes or generates code is bounded by `hookTimeout`, not `testTimeout`.
+
 ### Database
 - Use real in-memory SQLite for SmrtObject/SmrtCollection tests
 - `createIsolatedTestDb()` for transaction-isolated tests (rolls back on cleanup)
diff --git a/TESTING_STANDARD.md b/TESTING_STANDARD.md
index 8479920397..d63d486314 100644
--- a/TESTING_STANDARD.md
+++ b/TESTING_STANDARD.md
@@ -138,6 +138,31 @@ No field metadata found for 'Document'.
 
 **Note on watch mode**: The manifest is generated once at vitest startup. If you add new classes or fields while vitest is running in watch mode, restart vitest to pick up the changes.
 
+### ⚠️ Never raise `testTimeout` without raising `hookTimeout`
+
+`testTimeout` and `hookTimeout` are independent. Raising only `testTimeout`
+leaves every `beforeAll`/`beforeEach`/`afterAll`/`afterEach` on vitest's **10s
+default**, so a slow hook fails the whole file while the test bodies report as
+*skipped* — a failure mode that looks nothing like a timeout in the test you
+were budgeting for.
+
+```typescript
+test: {
+  testTimeout: 30000,
+  hookTimeout: 30000, // match testTimeout; hooks do not inherit it
+}
+```
+
+This has bitten the repo repeatedly: smrt-svelte's teardown hook (#1426), and
+`mcp-conformance-fixture`, whose `beforeAll` generates a server and spawns two
+`tsx` children — it measured 10,022ms against the 10,000ms default and ejected
+a PR from the merge queue (#2238). Packages run in shared CI shards, so a hook
+that overruns takes unrelated PRs down with it.
+
+Budget by **where the work happens**, not by where the assertions are: if setup
+does the expensive work (spawning processes, generating code, building
+bundles), `hookTimeout` is the limit that matters.
+
 ### Watch Mode
 
 ```bash
diff --git a/packages/mcp-conformance-fixture/vitest.config.ts b/packages/mcp-conformance-fixture/vitest.config.ts
index d536043279..4a5371e8cb 100644
--- a/packages/mcp-conformance-fixture/vitest.config.ts
+++ b/packages/mcp-conformance-fixture/vitest.config.ts
@@ -3,5 +3,16 @@ import { smrtVitestPlugin } from '../vitest/src/index.ts';
 
 export default defineConfig({
   plugins: [smrtVitestPlugin()],
-  test: { environment: 'node', testTimeout: 240_000 },
+  test: {
+    environment: 'node',
+    testTimeout: 240_000,
+    // Match testTimeout. Nearly all of this suite's work happens in `beforeAll`,
+    // not in the test bodies: it regenerates the MCP server with `MCPGenerator`,
+    // spawns a `tsx` child over stdio to negotiate the protocol and list tools,
+    // then spawns a second `tsx` child for the HTTP adapter. Left at vitest's
+    // 10s `hookTimeout` default that hook measured 10,022ms on a loaded runner
+    // and ejected PR #2230 from the merge queue (#2238). This package sits in
+    // the shared `test-packages` shard, so the miss was not local to that PR.
+    hookTimeout: 240_000,
+  },
 });