diff --git a/mobile/src/mobile-web/mobile-web-account-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-account-roundtrip.test.ts
index 742b27d9b6c..f9cf3e8e833 100644
--- a/mobile/src/mobile-web/mobile-web-account-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-account-roundtrip.test.ts
@@ -1,19 +1,8 @@
 import { expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import type { RpcClient } from '../transport/rpc-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
-
-const CONTEXT = {
-  shellSessionId: 'S'.repeat(43),
-  buildId: 'a'.repeat(64)
-}
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 
 it('round trips typed account reads, selection, and snapshots through the production bridge', async () => {
-  let broker: MobileWebCapabilityBroker
   let hostListener: ((event: unknown) => void) | null = null
   const hostUnsubscribe = vi.fn()
   const sendRequest = vi.fn(async (method: string) => {
@@ -31,46 +20,16 @@ it('round trips typed account reads, selection, and snapshots through the produc
   } as unknown as RpcClient
   const requestIds = ['A', 'B', 'C', 'D', 'E']
   let requestIndex = 0
-  const client = new MobileWebBridgeClient({
-    context: CONTEXT,
+  const { client, pageMessages, shellMessages } = createMobileWebBridgeRoundtripFixture({
     grants: [accountGrant('snapshot'), accountGrant('select'), accountGrant('subscribe')],
+    rpcClient,
     createRequestId: () => requestIds[requestIndex++]!.repeat(22),
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        return false
-      }
-      void broker.handle(parsed.value)
-      return true
-    }
-  })
-  broker = new MobileWebCapabilityBroker({
-    context: CONTEXT,
-    getClient: () => rpcClient,
-    isConnected: () => true,
-    isActive: () => true,
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        throw new Error(parsed.error)
-      }
-      client.receive(parsed.value)
-    },
-    nativeAuthority: {
-      hapticFeedback: vi.fn(),
-      clipboardWrite: vi.fn(),
-      openExternal: vi.fn(),
-      terminalPreferences: vi.fn(),
-      terminalTextScaleUpdate: vi.fn()
-    },
     navigationAuthority: {
       route: vi.fn(),
       reconnect: vi.fn(),
       removeHost: vi.fn(),
       consumeRecentUserGesture: () => true
-    },
-    terminalClientId: 'device-token',
-    randomBytes: (length) => new Uint8Array(length).fill(1)
+    }
   })
 
   await expect(client.account.snapshot()).resolves.toMatchObject({
@@ -79,6 +38,17 @@ it('round trips typed account reads, selection, and snapshots through the produc
       activeAccountId: 'claude-1'
     }
   })
+  expect(pageMessages[0]).toMatchObject({
+    type: 'request',
+    requestId: 'A'.repeat(22),
+    capability: 'account',
+    operation: 'snapshot'
+  })
+  expect(shellMessages[0]).toMatchObject({
+    type: 'response',
+    requestId: 'A'.repeat(22),
+    status: 'success'
+  })
   await expect(
     client.account.select({ provider: 'codex', accountId: 'codex-1' })
   ).resolves.toBeNull()
diff --git a/mobile/src/mobile-web/mobile-web-agent-history-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-agent-history-roundtrip.test.ts
index 1a2e6f278ca..5547649bb0f 100644
--- a/mobile/src/mobile-web/mobile-web-agent-history-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-agent-history-roundtrip.test.ts
@@ -1,19 +1,8 @@
 import { expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import type { RpcClient } from '../transport/rpc-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
-
-const CONTEXT = {
-  shellSessionId: 'S'.repeat(43),
-  buildId: 'a'.repeat(64)
-}
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 
 it('round trips opaque agent history and gesture-gates resume through the production bridge', async () => {
-  let broker: MobileWebCapabilityBroker
   const sendRequest = vi.fn(async (method: string) => {
     if (method === 'status.get') {
       return {
@@ -35,49 +24,20 @@ it('round trips opaque agent history and gesture-gates resume through the produc
   const rpcClient = { sendRequest } as unknown as RpcClient
   const requestIds = ['A', 'B', 'C']
   let requestIndex = 0
-  const client = new MobileWebBridgeClient({
-    context: CONTEXT,
+  const { broker, client } = createMobileWebBridgeRoundtripFixture({
     grants: [
       agentHistoryGrant('snapshot'),
       agentHistoryGrant('preview'),
       agentHistoryGrant('resume')
     ],
+    rpcClient,
     createRequestId: () => requestIds[requestIndex++]!.repeat(22),
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        return false
-      }
-      void broker.handle(parsed.value)
-      return true
-    }
-  })
-  broker = new MobileWebCapabilityBroker({
-    context: CONTEXT,
-    getClient: () => rpcClient,
-    isConnected: () => true,
-    isActive: () => true,
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        throw new Error(parsed.error)
-      }
-      client.receive(parsed.value)
-    },
-    nativeAuthority: {
-      hapticFeedback: vi.fn(),
-      clipboardWrite: vi.fn(),
-      openExternal: vi.fn(),
-      terminalPreferences: vi.fn(),
-      terminalTextScaleUpdate: vi.fn()
-    },
     navigationAuthority: {
       route: vi.fn(),
       reconnect: vi.fn(),
       removeHost: vi.fn(),
       consumeRecentUserGesture: () => false
     },
-    terminalClientId: 'device-token',
     randomBytes: (length) => new Uint8Array(length).fill(5)
   })
   const route = await broker.resolveNavigationRoute('host-workspace')
diff --git a/mobile/src/mobile-web/mobile-web-bridge-roundtrip-fixture.ts b/mobile/src/mobile-web/mobile-web-bridge-roundtrip-fixture.ts
new file mode 100644
index 00000000000..1aa55e9d403
--- /dev/null
+++ b/mobile/src/mobile-web/mobile-web-bridge-roundtrip-fixture.ts
@@ -0,0 +1,91 @@
+import { onTestFinished } from 'vitest'
+import {
+  parseMobileWebBridgePageMessage,
+  parseMobileWebBridgeShellMessage,
+  type MobileWebBridgeMessageContext,
+  type MobileWebBridgePageMessage,
+  type MobileWebBridgeShellMessage
+} from '../../../src/shared/mobile-web/bridge-contract'
+import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
+import type { RpcClient } from '../transport/rpc-client'
+import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import type { MobileWebNativeCapabilityAuthority } from './mobile-web-native-capability-authority'
+import type { MobileWebNavigationAuthority } from './mobile-web-navigation-operations'
+
+type InitMessage = Extract<MobileWebBridgeShellMessage, { type: 'init' }>
+
+export const MOBILE_WEB_BRIDGE_ROUNDTRIP_CONTEXT = {
+  shellSessionId: 'S'.repeat(43),
+  buildId: 'a'.repeat(64)
+}
+
+export function createMobileWebBridgeRoundtripFixture(options: {
+  grants: InitMessage['grants']
+  rpcClient?: RpcClient | null
+  context?: MobileWebBridgeMessageContext
+  createRequestId?: () => string
+  nativeAuthority?: Partial<MobileWebNativeCapabilityAuthority>
+  navigationAuthority?: MobileWebNavigationAuthority
+  isActive?: () => boolean
+  isConnected?: () => boolean
+  terminalClientId?: string
+  randomBytes?: (length: number) => Uint8Array
+}) {
+  const context = options.context ?? MOBILE_WEB_BRIDGE_ROUNDTRIP_CONTEXT
+  const pageMessages: MobileWebBridgePageMessage[] = []
+  const shellMessages: MobileWebBridgeShellMessage[] = []
+  let broker: MobileWebCapabilityBroker
+  const client = new MobileWebBridgeClient({
+    context,
+    grants: options.grants,
+    createRequestId: options.createRequestId,
+    postMessage(message) {
+      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), context)
+      if (!parsed.ok) {
+        return false
+      }
+      pageMessages.push(parsed.value)
+      void broker.handle(parsed.value)
+      return true
+    }
+  })
+  broker = new MobileWebCapabilityBroker({
+    context,
+    getClient: () => options.rpcClient ?? null,
+    isConnected: options.isConnected ?? (() => options.rpcClient != null),
+    isActive: options.isActive ?? (() => true),
+    nativeAuthority: { ...defaultNativeAuthority(), ...options.nativeAuthority },
+    navigationAuthority: options.navigationAuthority,
+    terminalClientId: options.terminalClientId ?? 'roundtrip-device',
+    randomBytes: options.randomBytes ?? ((length) => new Uint8Array(length).fill(1)),
+    postMessage(message) {
+      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), context)
+      if (!parsed.ok) {
+        throw new Error(parsed.error)
+      }
+      shellMessages.push(parsed.value)
+      client.receive(parsed.value)
+    }
+  })
+  const dispose = () => {
+    client.dispose()
+    broker.dispose()
+  }
+  onTestFinished(dispose)
+  return { broker, client, dispose, pageMessages, shellMessages }
+}
+
+function defaultNativeAuthority(): MobileWebNativeCapabilityAuthority {
+  return {
+    hapticFeedback: () => {},
+    clipboardAvailability: async () => ({ hasText: false, hasImage: false }),
+    clipboardWrite: async () => ({ confirmation: 'in-app' }),
+    openExternal: async () => {},
+    terminalPreferences: async () => ({
+      textScale: 1,
+      autocompleteEnabled: true,
+      linkOpenMode: 'phone-browser'
+    }),
+    terminalTextScaleUpdate: async () => {}
+  }
+}
diff --git a/mobile/src/mobile-web/mobile-web-bridge-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-bridge-roundtrip.test.ts
index a39837c2315..2b3d68a0489 100644
--- a/mobile/src/mobile-web/mobile-web-bridge-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-bridge-roundtrip.test.ts
@@ -1,15 +1,11 @@
 import { describe, expect, it, vi } from 'vitest'
 import {
   MOBILE_WEB_BRIDGE_PROTOCOL_VERSION,
-  parseMobileWebBridgePageMessage,
   parseMobileWebBridgeShellMessage
 } from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import type { RpcClient } from '../transport/rpc-client'
-import {
-  MOBILE_WEB_PRODUCTION_GRANTS,
-  MobileWebCapabilityBroker
-} from './mobile-web-capability-broker'
+import { MOBILE_WEB_PRODUCTION_GRANTS } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 
 const CONTEXT = {
   shellSessionId: 'S'.repeat(43),
@@ -149,7 +145,6 @@ describe('mobile web bridge round trip', () => {
       .mockResolvedValueOnce({ ok: true, result: { browserPageId: 'browser-2' } })
       .mockResolvedValueOnce({ ok: true, result: { closed: true } })
       .mockResolvedValueOnce({ ok: true, result: { opened: true } })
-    let broker: MobileWebCapabilityBroker
     let hostSubscriptionListener: ((event: unknown) => void) | undefined
     const hostUnsubscribe = vi.fn()
     const subscribe = vi
@@ -160,41 +155,13 @@ describe('mobile web bridge round trip', () => {
       })
     const requestIds = ['R', 'Q', 'T', 'U', 'V', 'W', 'X', 'Y', 'A', 'B']
     let requestIndex = 0
-    const client = new MobileWebBridgeClient({
+    const rpcClient = { sendRequest, subscribe } as unknown as RpcClient
+    const { client } = createMobileWebBridgeRoundtripFixture({
       context: CONTEXT,
       grants: [...MOBILE_WEB_PRODUCTION_GRANTS],
+      rpcClient,
       createRequestId: () => (requestIds[requestIndex++] ?? 'Z').repeat(22),
-      postMessage: (message) => {
-        const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          return false
-        }
-        void broker.handle(parsed.value)
-        return true
-      }
-    })
-    const rpcClient = { sendRequest, subscribe } as unknown as RpcClient
-    broker = new MobileWebCapabilityBroker({
-      context: CONTEXT,
-      getClient: () => rpcClient,
-      isConnected: () => true,
-      isActive: () => true,
-      nativeAuthority: {
-        hapticFeedback: vi.fn(),
-        clipboardWrite: vi.fn(),
-        openExternal: vi.fn(),
-        terminalPreferences: vi.fn(),
-        terminalTextScaleUpdate: vi.fn()
-      },
-      terminalClientId: 'device-token',
-      randomBytes: (length) => new Uint8Array(length).fill(1),
-      postMessage: (message) => {
-        const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          throw new Error(parsed.error)
-        }
-        client.receive(parsed.value)
-      }
+      terminalClientId: 'device-token'
     })
 
     const firstWorkspacePage = await client.workspaceSnapshot({ limit: 1 })
@@ -422,8 +389,5 @@ describe('mobile web bridge round trip', () => {
     expect(liveErrors).toEqual([])
     subscription.unsubscribe()
     expect(hostUnsubscribe).toHaveBeenCalledOnce()
-
-    client.dispose()
-    broker.dispose()
   })
 })
diff --git a/mobile/src/mobile-web/mobile-web-native-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-native-roundtrip.test.ts
index 78e70533b4b..647a608e3a0 100644
--- a/mobile/src/mobile-web/mobile-web-native-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-native-roundtrip.test.ts
@@ -1,17 +1,7 @@
 import { describe, expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import { MOBILE_WEB_PRODUCTION_NATIVE_GRANTS } from './mobile-web-production-native-grants'
 
-const CONTEXT = {
-  shellSessionId: 'S'.repeat(43),
-  buildId: 'a'.repeat(64)
-}
-
 describe('mobile web native capability round trip', () => {
   it('keeps device effects in the shell behind typed grants and gestures', async () => {
     const hapticFeedback = vi.fn()
@@ -30,26 +20,11 @@ describe('mobile web native capability round trip', () => {
     const terminalCustomKeysUpdate = vi.fn().mockResolvedValue(undefined)
     const terminalTextScaleUpdate = vi.fn().mockResolvedValue(undefined)
     const consumeRecentUserGesture = vi.fn(() => true)
-    let broker: MobileWebCapabilityBroker
     let requestIndex = 0
-    const client = new MobileWebBridgeClient({
-      context: CONTEXT,
+    const { client } = createMobileWebBridgeRoundtripFixture({
       grants: [...MOBILE_WEB_PRODUCTION_NATIVE_GRANTS],
       createRequestId: () => String.fromCharCode(65 + requestIndex++).repeat(22),
-      postMessage(message) {
-        const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          return false
-        }
-        void broker.handle(parsed.value)
-        return true
-      }
-    })
-    broker = new MobileWebCapabilityBroker({
-      context: CONTEXT,
-      getClient: () => null,
       isConnected: () => false,
-      isActive: () => true,
       nativeAuthority: {
         hapticFeedback,
         clipboardWrite,
@@ -64,15 +39,6 @@ describe('mobile web native capability round trip', () => {
         reconnect: vi.fn(),
         removeHost: vi.fn(),
         consumeRecentUserGesture
-      },
-      terminalClientId: 'native-only-device',
-      randomBytes: (length) => new Uint8Array(length),
-      postMessage(message) {
-        const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          throw new Error(parsed.error)
-        }
-        client.receive(parsed.value)
       }
     })
 
@@ -108,7 +74,5 @@ describe('mobile web native capability round trip', () => {
       { id: 'custom-2', label: 'Test', bytes: 'pnpm test\r', enter: false }
     ])
     expect(consumeRecentUserGesture).toHaveBeenCalledTimes(4)
-    client.dispose()
-    broker.dispose()
   })
 })
diff --git a/mobile/src/mobile-web/mobile-web-navigation-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-navigation-roundtrip.test.ts
index adb0f52ba8f..1daa7f62e1d 100644
--- a/mobile/src/mobile-web/mobile-web-navigation-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-navigation-roundtrip.test.ts
@@ -1,58 +1,23 @@
 import { describe, expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import { MOBILE_WEB_PRODUCTION_NAVIGATION_GRANTS } from './mobile-web-production-navigation-grants'
 
-const CONTEXT = {
-  shellSessionId: 'S'.repeat(43),
-  buildId: 'a'.repeat(64)
-}
-
 describe('mobile web navigation round trip', () => {
   it('carries named shell intent without host identity', async () => {
     const route = vi.fn()
     const reconnect = vi.fn()
     const removeHost = vi.fn()
     const consumeRecentUserGesture = vi.fn(() => true)
-    let broker: MobileWebCapabilityBroker
     let requestIndex = 0
-    const client = new MobileWebBridgeClient({
-      context: CONTEXT,
+    const { client } = createMobileWebBridgeRoundtripFixture({
       grants: [...MOBILE_WEB_PRODUCTION_NAVIGATION_GRANTS],
       createRequestId: () => String.fromCharCode(82 + requestIndex++).repeat(22),
-      postMessage(message) {
-        const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          return false
-        }
-        void broker.handle(parsed.value)
-        return true
-      }
-    })
-    broker = new MobileWebCapabilityBroker({
-      context: CONTEXT,
-      getClient: () => null,
       isConnected: () => false,
-      isActive: () => true,
-      nativeAuthority: nativeAuthority(),
       navigationAuthority: {
         route,
         reconnect,
         removeHost,
         consumeRecentUserGesture
-      },
-      terminalClientId: 'native-only-device',
-      randomBytes: (length) => new Uint8Array(length),
-      postMessage(message) {
-        const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          throw new Error(parsed.error)
-        }
-        client.receive(parsed.value)
       }
     })
 
@@ -68,17 +33,5 @@ describe('mobile web navigation round trip', () => {
     expect(reconnect).toHaveBeenCalledWith()
     expect(removeHost).toHaveBeenCalledWith()
     expect(consumeRecentUserGesture).toHaveBeenCalledTimes(3)
-    client.dispose()
-    broker.dispose()
   })
 })
-
-function nativeAuthority() {
-  return {
-    hapticFeedback: vi.fn(),
-    clipboardWrite: vi.fn(),
-    openExternal: vi.fn(),
-    terminalPreferences: vi.fn(),
-    terminalTextScaleUpdate: vi.fn()
-  }
-}
diff --git a/mobile/src/mobile-web/mobile-web-task-item-mutation-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-task-item-mutation-roundtrip.test.ts
index bc6b00fe76e..9f5faea48ea 100644
--- a/mobile/src/mobile-web/mobile-web-task-item-mutation-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-task-item-mutation-roundtrip.test.ts
@@ -1,9 +1,4 @@
 import { expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import { webHostTaskItemFileOperations } from '../tasks/web-host-task-item-file-operations'
 import { webHostTaskItemMutationOperations } from '../tasks/web-host-task-item-mutation-operations'
 import { webHostTaskItemReviewOperations } from '../tasks/web-host-task-item-review-operations'
@@ -12,7 +7,7 @@ import { webHostTaskProviderWriteOperations } from '../tasks/web-host-task-provi
 import { webHostTaskListOperations } from '../tasks/web-host-task-list-operations'
 import { webHostTaskReadOperations } from '../tasks/web-host-task-read-operations'
 import type { RpcClient } from '../transport/rpc-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import { taskRoundtripHostResponse } from './mobile-web-task-roundtrip-host-fixtures'
 
 const CONTEXT = {
@@ -21,11 +16,10 @@ const CONTEXT = {
 }
 
 it('revalidates opaque hosted task targets before provider writes', async () => {
-  let broker: MobileWebCapabilityBroker
   const sendRequest = vi.fn(async (method: string) => taskRoundtripHostResponse(method))
   const rpcClient = { sendRequest } as unknown as RpcClient
   let requestIndex = 0
-  const client = new MobileWebBridgeClient({
+  const { broker, client } = createMobileWebBridgeRoundtripFixture({
     context: CONTEXT,
     grants: [
       taskGrant('repositories'),
@@ -56,36 +50,9 @@ it('revalidates opaque hosted task targets before provider writes', async () =>
       taskGrant('createProviderIssue'),
       taskGrant('updateIssueSource')
     ],
+    rpcClient,
     createRequestId: () =>
       'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'[requestIndex++]!.repeat(22),
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        return false
-      }
-      void broker.handle(parsed.value)
-      return true
-    }
-  })
-  broker = new MobileWebCapabilityBroker({
-    context: CONTEXT,
-    getClient: () => rpcClient,
-    isConnected: () => true,
-    isActive: () => true,
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        throw new Error(parsed.error)
-      }
-      client.receive(parsed.value)
-    },
-    nativeAuthority: {
-      hapticFeedback: vi.fn(),
-      clipboardWrite: vi.fn(),
-      openExternal: vi.fn(),
-      terminalPreferences: vi.fn(),
-      terminalTextScaleUpdate: vi.fn()
-    },
     terminalClientId: 'device-token',
     randomBytes: (length) => new Uint8Array(length).fill(4)
   })
diff --git a/mobile/src/mobile-web/mobile-web-task-project-mutation-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-task-project-mutation-roundtrip.test.ts
index e98ff671539..d946fb5fc3a 100644
--- a/mobile/src/mobile-web/mobile-web-task-project-mutation-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-task-project-mutation-roundtrip.test.ts
@@ -1,15 +1,10 @@
 import { expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import { webHostTaskProjectFileOperations } from '../tasks/web-host-task-project-file-operations'
 import { webHostTaskProjectMutationOperations } from '../tasks/web-host-task-project-mutation-operations'
 import { webHostTaskProjectReadOperations } from '../tasks/web-host-task-project-read-operations'
 import { webHostTaskReadOperations } from '../tasks/web-host-task-read-operations'
 import type { RpcClient } from '../transport/rpc-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import { taskRoundtripHostResponse } from './mobile-web-task-roundtrip-host-fixtures'
 
 const CONTEXT = {
@@ -18,11 +13,10 @@ const CONTEXT = {
 }
 
 it('revalidates opaque GitHub Project mutation targets before every write', async () => {
-  let broker: MobileWebCapabilityBroker
   const sendRequest = vi.fn(async (method: string) => taskRoundtripHostResponse(method))
   const rpcClient = { sendRequest } as unknown as RpcClient
   let requestIndex = 0
-  const client = new MobileWebBridgeClient({
+  const { broker, client } = createMobileWebBridgeRoundtripFixture({
     context: CONTEXT,
     grants: [
       taskGrant('repositories'),
@@ -45,35 +39,8 @@ it('revalidates opaque GitHub Project mutation targets before every write', asyn
       taskGrant('loadProjectFileContents'),
       taskGrant('addProjectInlineComment')
     ],
+    rpcClient,
     createRequestId: () => String.fromCharCode(65 + requestIndex++).repeat(22),
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        return false
-      }
-      void broker.handle(parsed.value)
-      return true
-    }
-  })
-  broker = new MobileWebCapabilityBroker({
-    context: CONTEXT,
-    getClient: () => rpcClient,
-    isConnected: () => true,
-    isActive: () => true,
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        throw new Error(parsed.error)
-      }
-      client.receive(parsed.value)
-    },
-    nativeAuthority: {
-      hapticFeedback: vi.fn(),
-      clipboardWrite: vi.fn(),
-      openExternal: vi.fn(),
-      terminalPreferences: vi.fn(),
-      terminalTextScaleUpdate: vi.fn()
-    },
     terminalClientId: 'device-token',
     randomBytes: (length) => new Uint8Array(length).fill(3)
   })
diff --git a/mobile/src/mobile-web/mobile-web-task-read-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-task-read-roundtrip.test.ts
index 3f27bd199f4..a6f93685a08 100644
--- a/mobile/src/mobile-web/mobile-web-task-read-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-task-read-roundtrip.test.ts
@@ -1,16 +1,11 @@
 import { expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import { webHostTaskPreferenceOperations } from '../tasks/web-host-task-preference-operations'
 import { webHostTaskDetailOperations } from '../tasks/web-host-task-detail-operations'
 import { webHostTaskProjectReadOperations } from '../tasks/web-host-task-project-read-operations'
 import { webHostTaskListOperations } from '../tasks/web-host-task-list-operations'
 import { webHostTaskReadOperations } from '../tasks/web-host-task-read-operations'
 import type { RpcClient } from '../transport/rpc-client'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import {
   TASK_ROUNDTRIP_HOST_REPO_ID,
   taskRoundtripHostResponse
@@ -21,11 +16,10 @@ const CONTEXT = {
   buildId: 'a'.repeat(64)
 }
 it('round trips bounded task bootstrap reads through opaque repository authority', async () => {
-  let broker: MobileWebCapabilityBroker
   const sendRequest = vi.fn(async (method: string) => taskRoundtripHostResponse(method))
   const rpcClient = { sendRequest } as unknown as RpcClient
   let requestIndex = 0
-  const client = new MobileWebBridgeClient({
+  const { broker, client } = createMobileWebBridgeRoundtripFixture({
     context: CONTEXT,
     grants: [
       taskGrant('bootstrap'),
@@ -53,37 +47,9 @@ it('round trips bounded task bootstrap reads through opaque repository authority
       taskGrant('projectItemAssignableUsers'),
       taskGrant('projectIssueTypes')
     ],
+    rpcClient,
     createRequestId: () => String.fromCharCode(65 + requestIndex++).repeat(22),
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        return false
-      }
-      void broker.handle(parsed.value)
-      return true
-    }
-  })
-  broker = new MobileWebCapabilityBroker({
-    context: CONTEXT,
-    getClient: () => rpcClient,
-    isConnected: () => true,
-    isActive: () => true,
-    postMessage: (message) => {
-      const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-      if (!parsed.ok) {
-        throw new Error(parsed.error)
-      }
-      client.receive(parsed.value)
-    },
-    nativeAuthority: {
-      hapticFeedback: vi.fn(),
-      clipboardWrite: vi.fn(),
-      openExternal: vi.fn(),
-      terminalPreferences: vi.fn(),
-      terminalTextScaleUpdate: vi.fn()
-    },
-    terminalClientId: 'device-token',
-    randomBytes: (length) => new Uint8Array(length).fill(1)
+    terminalClientId: 'device-token'
   })
   const operations = webHostTaskReadOperations(client)
   const lists = webHostTaskListOperations(client)
diff --git a/mobile/src/mobile-web/mobile-web-workspace-creation-roundtrip.test.ts b/mobile/src/mobile-web/mobile-web-workspace-creation-roundtrip.test.ts
index f01bbb6d96c..da819a6689d 100644
--- a/mobile/src/mobile-web/mobile-web-workspace-creation-roundtrip.test.ts
+++ b/mobile/src/mobile-web/mobile-web-workspace-creation-roundtrip.test.ts
@@ -1,23 +1,11 @@
 import { describe, expect, it, vi } from 'vitest'
-import {
-  parseMobileWebBridgePageMessage,
-  parseMobileWebBridgeShellMessage,
-  type MobileWebBridgeShellMessage
-} from '../../../src/shared/mobile-web/bridge-contract'
-import { MobileWebBridgeClient } from '../../../src/mobile-web/src/mobile-web-bridge-client'
 import type { RpcClient } from '../transport/rpc-client'
 import { MOBILE_WORKTREE_CREATE_IDEMPOTENCY_CAPABILITY } from '../tasks/worktree-create-capability'
-import { MobileWebCapabilityBroker } from './mobile-web-capability-broker'
+import { createMobileWebBridgeRoundtripFixture } from './mobile-web-bridge-roundtrip-fixture'
 import { MOBILE_WEB_PRODUCTION_WORKSPACE_CREATION_GRANTS } from './mobile-web-production-workspace-creation-grants'
 
-const CONTEXT = {
-  shellSessionId: 'S'.repeat(43),
-  buildId: 'a'.repeat(64)
-}
-
 describe('mobile web workspace creation round trip', () => {
   it('carries page requests through schemas and resolves host authority only in native', async () => {
-    const shellMessages: MobileWebBridgeShellMessage[] = []
     const consumeRecentUserGesture = vi.fn(() => true)
     const sendRequest = vi.fn(async (method: string) => {
       if (method === 'repo.list') {
@@ -47,48 +35,17 @@ describe('mobile web workspace creation round trip', () => {
       throw new Error(`Unexpected method ${method}`)
     })
     const hostClient = { sendRequest } as unknown as RpcClient
-    let broker: MobileWebCapabilityBroker
     let requestIndex = 0
-    const pageClient = new MobileWebBridgeClient({
-      context: CONTEXT,
+    const { client: pageClient, shellMessages } = createMobileWebBridgeRoundtripFixture({
       grants: [...MOBILE_WEB_PRODUCTION_WORKSPACE_CREATION_GRANTS],
+      rpcClient: hostClient,
       createRequestId: () => String.fromCharCode(65 + requestIndex++).repeat(22),
-      postMessage(message) {
-        const parsed = parseMobileWebBridgePageMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          return false
-        }
-        void broker.handle(parsed.value)
-        return true
-      }
-    })
-    broker = new MobileWebCapabilityBroker({
-      context: CONTEXT,
-      getClient: () => hostClient,
-      isConnected: () => true,
-      isActive: () => true,
-      nativeAuthority: {
-        hapticFeedback: vi.fn(),
-        clipboardWrite: vi.fn(),
-        openExternal: vi.fn(),
-        terminalPreferences: vi.fn(),
-        terminalTextScaleUpdate: vi.fn()
-      },
-      terminalClientId: 'native-device-secret',
       randomBytes: (length) => new Uint8Array(length).fill(5),
       navigationAuthority: {
         route: vi.fn(),
         reconnect: vi.fn(),
         removeHost: vi.fn(),
         consumeRecentUserGesture
-      },
-      postMessage(message) {
-        shellMessages.push(message)
-        const parsed = parseMobileWebBridgeShellMessage(JSON.stringify(message), CONTEXT)
-        if (!parsed.ok) {
-          throw new Error(parsed.error)
-        }
-        pageClient.receive(parsed.value)
       }
     })
 
@@ -132,8 +89,5 @@ describe('mobile web workspace creation round trip', () => {
     expect(createParams).not.toHaveProperty('startupCommand')
     expect(sendRequest).not.toHaveBeenCalledWith('settings.get')
     expect(JSON.stringify(shellMessages)).not.toMatch(/repo-secret|worktree-secret|ssh-private-id/)
-
-    pageClient.dispose()
-    broker.dispose()
   })
 })