diff --git a/chat-client/src/client/chat.test.ts b/chat-client/src/client/chat.test.ts
index efd08da81d..89fef60238 100644
--- a/chat-client/src/client/chat.test.ts
+++ b/chat-client/src/client/chat.test.ts
@@ -30,7 +30,14 @@ import { MynahUI } from '@aws/mynah-ui'
 import { TabFactory } from './tabs/tabFactory'
 import { ChatClientAdapter } from '../contracts/chatClientAdapter'
 
-describe('Chat', () => {
+describe('Chat', function () {
+    /**
+     * Also jsdom-backed: the slowest cases here reach ~570ms idle and 3.5s under load,
+     * i.e. 70% of the default 5s budget, so they are the next to flake. See the note in
+     * mynahUi.test.ts.
+     */
+    this.timeout(30_000)
+
     const sandbox = sinon.createSandbox()
     const initialTabId = 'tab-1'
     let mynahUi: MynahUI
diff --git a/chat-client/src/client/mynahUi.test.ts b/chat-client/src/client/mynahUi.test.ts
index a69cf883c7..34ede0cb5b 100644
--- a/chat-client/src/client/mynahUi.test.ts
+++ b/chat-client/src/client/mynahUi.test.ts
@@ -18,7 +18,18 @@ import { ChatHistory } from './features/history'
 import { pairProgrammingModeOn, pairProgrammingModeOff } from './texts/pairProgramming'
 import { strictEqual } from 'assert'
 
-describe('MynahUI', () => {
+describe('MynahUI', function () {
+    /**
+     * These tests drive the real MynahUI against jsdom, so creating a tab performs several
+     * hundred milliseconds of synchronous DOM work -- up to ~1.8s for the sendGenericCommand
+     * cases on an idle developer machine. Mocha reports a synchronous test that overruns its
+     * budget as "Timeout of Nms exceeded", so on a loaded CI runner (measured 4.6-7x slower)
+     * the default 5s budget is exceeded and the suite fails on whichever test is unlucky.
+     * One generous budget for the whole suite replaces the per-test 10s/30s patches that
+     * were added for the same reason.
+     */
+    this.timeout(30_000)
+
     let messager: Messager
     let mynahUi: MynahUI
     let inboundChatApi: InboundChatApi
@@ -248,7 +259,6 @@ describe('MynahUI', () => {
 
     describe('sendGenericCommand', () => {
         it('should create a new tab if none exits', function () {
-            this.timeout(10000) // Increase timeout to 10 seconds
             // clear create tab stub since set up process calls it twice
             createTabStub.resetHistory()
             // Stub setTimeout to execute immediately
@@ -275,7 +285,6 @@ describe('MynahUI', () => {
         })
 
         it('should create a new tab if current tab is loading', function () {
-            this.timeout(30000)
             // clear create tab stub since set up process calls it twice
             createTabStub.resetHistory()
             // Stub setTimeout to execute immediately