diff --git a/apps/desktop/src/hermes.test.ts b/apps/desktop/src/hermes.test.ts
index 46a7cef5f928..f829471c5a33 100644
--- a/apps/desktop/src/hermes.test.ts
+++ b/apps/desktop/src/hermes.test.ts
@@ -1,6 +1,12 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 
 import {
+  AUDIO_SPEAK_MAX_REQUEST_TIMEOUT_MS,
+  AUDIO_SPEAK_MIN_REQUEST_TIMEOUT_MS,
+  AUDIO_TRANSCRIBE_MAX_REQUEST_TIMEOUT_MS,
+  AUDIO_TRANSCRIBE_MIN_REQUEST_TIMEOUT_MS,
+  audioSpeakRequestTimeoutMs,
+  audioTranscribeRequestTimeoutMs,
   getCronJobs,
   getGlobalModelInfo,
   getGlobalModelOptions,
@@ -12,7 +18,9 @@ import {
   listAllProfileSessions,
   listSessions,
   listSidebarSessions,
-  resetSidebarBatchCapability
+  resetSidebarBatchCapability,
+  speakText,
+  transcribeAudio
 } from './hermes'
 import { refreshActiveProfile } from './store/profile'
 
@@ -23,7 +31,7 @@ const emptySessionsResponse = {
   total: 0
 }
 
-describe('Hermes REST session helpers', () => {
+describe('Hermes REST helpers', () => {
   let api: ReturnType<typeof vi.fn>
 
   beforeEach(() => {
@@ -322,6 +330,62 @@ describe('Hermes REST session helpers', () => {
     })
   })
 
+  it('bounds blocking TTS synthesis timeouts by text length', () => {
+    expect(audioSpeakRequestTimeoutMs('short message')).toBe(AUDIO_SPEAK_MIN_REQUEST_TIMEOUT_MS)
+    expect(audioSpeakRequestTimeoutMs('x'.repeat(8_000))).toBe(280_000)
+    expect(audioSpeakRequestTimeoutMs('x'.repeat(100_000))).toBe(AUDIO_SPEAK_MAX_REQUEST_TIMEOUT_MS)
+  })
+
+  it('uses an extended timeout for blocking TTS synthesis', async () => {
+    api.mockResolvedValueOnce({
+      data_url: 'data:audio/mpeg;base64,AA==',
+      mime_type: 'audio/mpeg',
+      ok: true,
+      provider: 'openai'
+    })
+
+    await expect(speakText('Read this aloud')).resolves.toEqual({
+      data_url: 'data:audio/mpeg;base64,AA==',
+      mime_type: 'audio/mpeg',
+      ok: true,
+      provider: 'openai'
+    })
+
+    expect(api).toHaveBeenCalledWith({
+      body: { text: 'Read this aloud' },
+      method: 'POST',
+      path: '/api/audio/speak',
+      timeoutMs: AUDIO_SPEAK_MIN_REQUEST_TIMEOUT_MS
+    })
+  })
+
+  it('bounds blocking transcription timeouts by payload length', () => {
+    expect(audioTranscribeRequestTimeoutMs('data:audio/webm;base64,AA==')).toBe(AUDIO_TRANSCRIBE_MIN_REQUEST_TIMEOUT_MS)
+    expect(audioTranscribeRequestTimeoutMs('x'.repeat(3_000_000))).toBe(300_000)
+    expect(audioTranscribeRequestTimeoutMs('x'.repeat(9_000_000))).toBe(AUDIO_TRANSCRIBE_MAX_REQUEST_TIMEOUT_MS)
+  })
+
+  it('uses an extended timeout for blocking transcription', async () => {
+    api.mockResolvedValueOnce({
+      ok: true,
+      provider: 'openai',
+      text: 'transcribed text'
+    })
+
+    await expect(transcribeAudio('data:audio/webm;base64,AA==', 'audio/webm')).resolves.toEqual({
+      ok: true,
+      provider: 'openai',
+      text: 'transcribed text'
+    })
+
+    expect(api).toHaveBeenCalledWith({
+      body: { data_url: 'data:audio/webm;base64,AA==', mime_type: 'audio/webm' },
+      method: 'POST',
+      path: '/api/audio/transcribe',
+      timeoutMs: AUDIO_TRANSCRIBE_MIN_REQUEST_TIMEOUT_MS
+    })
+  })
+
   it('defaults model options to configured providers only', async () => {
     await getGlobalModelOptions()
 
diff --git a/apps/desktop/src/hermes.ts b/apps/desktop/src/hermes.ts
index d84f85815d85..a3d4199fa789 100644
--- a/apps/desktop/src/hermes.ts
+++ b/apps/desktop/src/hermes.ts
@@ -84,6 +84,36 @@ const SESSION_LIST_REQUEST_TIMEOUT_MS = 60_000
 // agent-turn ceiling (agent.gateway_timeout = 1800s) so the ack timeout only
 // ever fires when the turn itself would have been abandoned server-side.
 export const PROMPT_SUBMIT_REQUEST_TIMEOUT_MS = 1_800_000
+export const AUDIO_SPEAK_MIN_REQUEST_TIMEOUT_MS = 180_000
+export const AUDIO_SPEAK_MAX_REQUEST_TIMEOUT_MS = 600_000
+const AUDIO_SPEAK_TIMEOUT_MS_PER_CHAR = 35
+
+export function audioSpeakRequestTimeoutMs(text: string): number {
+  const estimated = Math.max(
+    AUDIO_SPEAK_MIN_REQUEST_TIMEOUT_MS,
+    Math.ceil(String(text || '').length * AUDIO_SPEAK_TIMEOUT_MS_PER_CHAR)
+  )
+
+  return Math.min(AUDIO_SPEAK_MAX_REQUEST_TIMEOUT_MS, estimated)
+}
+
+export const AUDIO_TRANSCRIBE_MIN_REQUEST_TIMEOUT_MS = 180_000
+export const AUDIO_TRANSCRIBE_MAX_REQUEST_TIMEOUT_MS = 600_000
+// The transcribe payload is the base64 audio data URL itself, so its string
+// length tracks clip size. ~0.1ms/char keeps short clips at the floor while
+// letting multi-minute recordings scale toward the cap (a base64 char is
+// ~0.75 bytes, so at 128kbps ≈ 21k chars/s of audio this budgets ~2s of
+// timeout per 1s of audio before the cap clamps it).
+const AUDIO_TRANSCRIBE_TIMEOUT_MS_PER_CHAR = 0.1
+
+export function audioTranscribeRequestTimeoutMs(dataUrl: string): number {
+  const estimated = Math.max(
+    AUDIO_TRANSCRIBE_MIN_REQUEST_TIMEOUT_MS,
+    Math.ceil(String(dataUrl || '').length * AUDIO_TRANSCRIBE_TIMEOUT_MS_PER_CHAR)
+  )
+
+  return Math.min(AUDIO_TRANSCRIBE_MAX_REQUEST_TIMEOUT_MS, estimated)
+}
 
 export type {
   ActionResponse,
@@ -1346,7 +1376,11 @@ export function transcribeAudio(dataUrl: string, mimeType?: string): Promise<Aud
     body: {
       data_url: dataUrl,
       mime_type: mimeType
-    }
+    },
+    // Transcription blocks until provider STT, file handling, and response
+    // encoding finish. Remote providers and long clips regularly exceed the
+    // default 15s Electron backend timeout.
+    timeoutMs: audioTranscribeRequestTimeoutMs(dataUrl)
   })
 }
 
@@ -1354,7 +1388,11 @@ export function speakText(text: string): Promise<AudioSpeakResponse> {
   return window.hermesDesktop.api<AudioSpeakResponse>({
     path: '/api/audio/speak',
     method: 'POST',
-    body: { text }
+    body: { text },
+    // TTS blocks until provider synthesis, file read, and base64 encoding
+    // finish. Remote providers and large messages regularly exceed the
+    // default 15s Electron backend timeout.
+    timeoutMs: audioSpeakRequestTimeoutMs(text)
   })
 }