diff --git a/packages/testing/contract.ts b/packages/testing/contract.ts
index c43dd5a..de56d06 100644
--- a/packages/testing/contract.ts
+++ b/packages/testing/contract.ts
@@ -32,6 +32,7 @@ import {
   UnknownIdentity,
 } from '@commy/core/ports'
 import { Duration, Effect, Exit, Option, Queue, type Scope, Stream } from 'effect'
+import { REALM_HOOK_TIMEOUT_MS } from './realm-hooks.ts'
 
 export interface ContractEnv {
   /**
@@ -110,9 +111,9 @@ export const runAgentCommsContract = (label: string, factory: ContractFactory):
 
     beforeEach(async () => {
       env = await factory()
-    })
+    }, REALM_HOOK_TIMEOUT_MS)
 
-    afterEach(() => Effect.runPromise(env.dispose()))
+    afterEach(() => Effect.runPromise(env.dispose()), REALM_HOOK_TIMEOUT_MS)
 
     test('publisher.post returns a MessageRef whose channel matches the destination', () =>
       Effect.runPromise(
diff --git a/packages/testing/realm-hooks.ts b/packages/testing/realm-hooks.ts
new file mode 100644
index 0000000..82f3f79
--- /dev/null
+++ b/packages/testing/realm-hooks.ts
@@ -0,0 +1,39 @@
+import { afterEach, beforeEach } from 'bun:test'
+
+/**
+ * bun:test lifecycle hooks keep their own 5s timeout, independent of any
+ * per-test timeout. In isolation a real in-process realm starts and stops in a
+ * few ms, but under a full-parallel `bun run check` the starved event loop can
+ * stretch that setup/teardown past 5s — and then the HOOK, not the test body,
+ * times out, landing the failure on whichever test the hook happened to be
+ * wrapping (comms-xwqm). 30s gives that contention wide headroom while still
+ * failing if a hook genuinely wedges.
+ *
+ * This is headroom, not a cure-all: the long-poll teardown tests (the
+ * gap-replay / scope-close-interrupt cases that drive an infinite server
+ * handler and rely on AbortSignal unwinding a forked drain fiber) can still
+ * exceed even this under aggressive contention. That residual is a fiber/scope
+ * lifecycle problem, not a too-small-number problem, and is tracked for the
+ * Effect-Scope-based realm rework (comms-4lz5 / comms-30hq) — running the whole
+ * test, realm acquisition included, inside one scope with guaranteed finalizers
+ * removes the leftover-fiber-starves-teardown failure mode structurally.
+ */
+export const REALM_HOOK_TIMEOUT_MS = 30_000
+
+/**
+ * Register per-test realm lifecycle on the bun:test hooks — a fresh instance
+ * before each test, stopped after — with the contention-proof timeout above.
+ * The caller keeps its own directly-referenced binding via `assign`, so
+ * existing `realm.` / `fixture.` call sites stay untouched.
+ */
+export const registerRealmHooks = <T extends { readonly stop: () => Promise<void> }>(
+  start: () => T,
+  assign: (instance: T) => void,
+): void => {
+  let instance: T
+  beforeEach(() => {
+    instance = start()
+    assign(instance)
+  }, REALM_HOOK_TIMEOUT_MS)
+  afterEach(() => instance.stop(), REALM_HOOK_TIMEOUT_MS)
+}
diff --git a/packages/zulip/adapter.test.ts b/packages/zulip/adapter.test.ts
index d63c371..39760d1 100644
--- a/packages/zulip/adapter.test.ts
+++ b/packages/zulip/adapter.test.ts
@@ -1,4 +1,4 @@
-import { afterEach, beforeEach, expect, test } from 'bun:test'
+import { expect, test } from 'bun:test'
 import type { ChannelRef, Identity, InboundEvent, MessageRef } from '@commy/core/ports'
 import {
   DirectoryError,
@@ -17,6 +17,7 @@ import {
   UnknownChannel,
   type UnknownIdentity,
 } from '@commy/core/ports'
+import { registerRealmHooks } from '@commy/testing/realm-hooks'
 import { FetchHttpClient, HttpClient } from '@effect/platform'
 import { Cause, Duration, Effect, Exit, Option, Queue, Redacted, type Scope, Stream } from 'effect'
 import type { ZulipAdapter, ZulipAdapterConfig } from './adapter.ts'
@@ -27,12 +28,8 @@ import { startTestRealm } from './test-server.ts'
 
 let realm: TestRealm
 
-beforeEach(() => {
-  realm = startTestRealm()
-})
-
-afterEach(async () => {
-  await realm.stop()
+registerRealmHooks(startTestRealm, (next) => {
+  realm = next
 })
 
 const HERMES = {
diff --git a/packages/zulip/bot-dm-guard.test.ts b/packages/zulip/bot-dm-guard.test.ts
index cd816a8..958da2f 100644
--- a/packages/zulip/bot-dm-guard.test.ts
+++ b/packages/zulip/bot-dm-guard.test.ts
@@ -1,4 +1,5 @@
-import { afterEach, beforeEach, expect, test } from 'bun:test'
+import { expect, test } from 'bun:test'
+import { registerRealmHooks } from '@commy/testing/realm-hooks'
 import { FetchHttpClient, HttpClient } from '@effect/platform'
 import { Cause, Effect, Exit, Option, Schema } from 'effect'
 import { BotToBotDirectMessageError, type RecipientDirectory, wrapBotHttp } from './bot-dm-guard.ts'
@@ -9,12 +10,8 @@ import { ZulipUserRef } from './user-ref.ts'
 
 let realm: TestRealm
 
-beforeEach(() => {
-  realm = startTestRealm()
-})
-
-afterEach(async () => {
-  await realm.stop()
+registerRealmHooks(startTestRealm, (next) => {
+  realm = next
 })
 
 const SELF_ID = ZulipUserRef(100)
diff --git a/packages/zulip/http.test.ts b/packages/zulip/http.test.ts
index 33fdf8a..7a0d80a 100644
--- a/packages/zulip/http.test.ts
+++ b/packages/zulip/http.test.ts
@@ -1,4 +1,5 @@
-import { afterEach, beforeEach, expect, test } from 'bun:test'
+import { expect, test } from 'bun:test'
+import { registerRealmHooks } from '@commy/testing/realm-hooks'
 import { FetchHttpClient, HttpClient } from '@effect/platform'
 import {
   Cause,
@@ -115,12 +116,8 @@ const startFixture = (): Fixture => {
 
 let fixture: Fixture
 
-beforeEach(() => {
-  fixture = startFixture()
-})
-
-afterEach(async () => {
-  await fixture.stop()
+registerRealmHooks(startFixture, (next) => {
+  fixture = next
 })
 
 const successSchema = Schema.Struct({ result: Schema.Literal('success') })