diff --git a/web/src/realtime/hooks/contextFormatters.test.ts b/web/src/realtime/hooks/contextFormatters.test.ts
index c2b4ac75..b1692edf 100644
--- a/web/src/realtime/hooks/contextFormatters.test.ts
+++ b/web/src/realtime/hooks/contextFormatters.test.ts
@@ -125,7 +125,7 @@ describe('formatReadyEvent', () => {
 })
 
 describe('formatMessage', () => {
-    it('formats codex stream-json assistant messages for voice context', () => {
+    it('uses the supplied agent label as the assistant prefix', () => {
         const formatted = formatMessage(msg({
             id: '1',
             seq: 1,
@@ -139,12 +139,33 @@ describe('formatMessage', () => {
                     }
                 }
             }
-        }))
+        }), 'Codex')
 
-        expect(formatted).toContain('Claude Code:')
+        expect(formatted).toContain('Codex:')
+        expect(formatted).not.toContain('Claude Code')
         expect(formatted).toContain('<text>Indexed 5,018 items in the search database.</text>')
     })
 
+    it('threads agentLabel for a different flavor (regression for #680)', () => {
+        const formatted = formatMessage(msg({
+            id: '1',
+            seq: 1,
+            content: {
+                role: 'agent',
+                content: {
+                    type: 'codex',
+                    data: {
+                        type: 'message',
+                        message: 'Cursor is generating a plan.'
+                    }
+                }
+            }
+        }), 'Cursor')
+
+        expect(formatted).toContain('Cursor:')
+        expect(formatted).not.toContain('Claude Code')
+    })
+
     it('ignores codex ready and tool-call payloads', () => {
         expect(formatMessage(msg({
             id: '1',
@@ -156,7 +177,7 @@ describe('formatMessage', () => {
                     data: { type: 'ready' }
                 }
             }
-        }))).toBeNull()
+        }), 'Codex')).toBeNull()
     })
 
     it('does not treat session status events as speakable assistant text', () => {
@@ -171,10 +192,10 @@ describe('formatMessage', () => {
                     data: { type: 'message', message: 'Aborting task.' }
                 }
             }
-        }))).toBeNull()
+        }), 'Codex')).toBeNull()
     })
 
-    it('preserves tool-call context for mixed text+tool_use content array', () => {
+    it('preserves tool-call context for mixed text+tool_use content array and uses the agent label', () => {
         const formatted = formatMessage(msg({
             id: '1',
             seq: 1,
@@ -185,10 +206,11 @@ describe('formatMessage', () => {
                     { type: 'tool_use', name: 'Bash', input: { command: 'ls' } }
                 ]
             }
-        }))
+        }), 'Claude')
 
         expect(formatted).toContain('Here is the result.')
-        expect(formatted).toContain('Claude Code is using Bash')
+        expect(formatted).toContain('Claude is using Bash')
+        expect(formatted).not.toContain('Claude Code is using')
     })
 })
 
@@ -209,9 +231,11 @@ describe('formatNewMessages', () => {
                     }
                 }
             })
-        ])
+        ], 'Codex')
 
         expect(update).toContain('New messages in session: session-1')
         expect(update).toContain('Local database file size is 2.43 GiB.')
+        expect(update).toContain('Codex:')
+        expect(update).not.toContain('Claude Code')
     })
 })
diff --git a/web/src/realtime/hooks/contextFormatters.ts b/web/src/realtime/hooks/contextFormatters.ts
index 98768429..54443925 100644
--- a/web/src/realtime/hooks/contextFormatters.ts
+++ b/web/src/realtime/hooks/contextFormatters.ts
@@ -66,32 +66,39 @@ function unwrapOutputContent(content: unknown): { roleOverride: NormalizedRole |
     return { roleOverride, content: messageContent }
 }
 
-function formatPlainText(role: NormalizedRole | null, text: string): string {
+function formatPlainText(role: NormalizedRole | null, text: string, agentLabel: string): string {
     if (role === 'assistant') {
-        return `Claude Code: \n<text>${text}</text>`
+        return `${agentLabel}: \n<text>${text}</text>`
     }
     return `User sent message: \n<text>${text}</text>`
 }
 
 /**
- * Format a permission request for natural language context
+ * Format a permission request for natural language context.
+ *
+ * `agentLabel` is the display label for the session's agent flavor
+ * (e.g. "Claude", "Cursor", "Codex"); voiceHooks computes it once per call.
  */
 export function formatPermissionRequest(
     sessionId: string,
     requestId: string,
     toolName: string,
-    toolArgs: unknown
+    toolArgs: unknown,
+    agentLabel: string
 ): string {
-    return `Claude Code is requesting permission to use ${toolName} (session ${sessionId}):
+    return `${agentLabel} is requesting permission to use ${toolName} (session ${sessionId}):
 <request_id>${requestId}</request_id>
 <tool_name>${toolName}</tool_name>
 <tool_args>${JSON.stringify(toolArgs)}</tool_args>`
 }
 
 /**
- * Format a single message for voice context
+ * Format a single message for voice context.
+ *
+ * `agentLabel` is the display label for the session's agent flavor
+ * (e.g. "Claude", "Cursor", "Codex"); voiceHooks computes it once per call.
  */
-export function formatMessage(message: DecryptedMessage): string | null {
+export function formatMessage(message: DecryptedMessage, agentLabel: string): string | null {
     const { role, content: wrappedContent } = unwrapRoleWrappedContent(message)
     const { roleOverride, content } = unwrapOutputContent(wrappedContent)
     const normalizedRole = roleOverride ?? role
@@ -103,7 +110,7 @@ export function formatMessage(message: DecryptedMessage): string | null {
     const speakable = !isContentArray(content) ? extractSpeakableFromContent(content) : null
     if (speakable) {
         const roleForFormat = normalizedRole === 'user' ? 'user' : 'assistant'
-        return formatPlainText(roleForFormat, speakable)
+        return formatPlainText(roleForFormat, speakable, agentLabel)
     }
 
     if (!isContentArray(content)) {
@@ -122,13 +129,13 @@ export function formatMessage(message: DecryptedMessage): string | null {
 
     for (const item of content) {
         if (item.type === 'text' && item.text) {
-            lines.push(formatPlainText(isAssistant ? 'assistant' : 'user', item.text))
+            lines.push(formatPlainText(isAssistant ? 'assistant' : 'user', item.text, agentLabel))
         } else if (item.type === 'tool_use' && !VOICE_CONFIG.DISABLE_TOOL_CALLS) {
             const name = item.name || 'unknown'
             if (VOICE_CONFIG.LIMITED_TOOL_CALLS) {
-                lines.push(`Claude Code is using ${name}`)
+                lines.push(`${agentLabel} is using ${name}`)
             } else {
-                lines.push(`Claude Code is using ${name} with arguments: <arguments>${JSON.stringify(item.input)}</arguments>`)
+                lines.push(`${agentLabel} is using ${name} with arguments: <arguments>${JSON.stringify(item.input)}</arguments>`)
             }
         }
     }
@@ -214,18 +221,18 @@ export function extractLastAssistantSpeakable(messages: DecryptedMessage[]): str
     return null
 }
 
-export function formatNewSingleMessage(sessionId: string, message: DecryptedMessage): string | null {
-    const formatted = formatMessage(message)
+export function formatNewSingleMessage(sessionId: string, message: DecryptedMessage, agentLabel: string): string | null {
+    const formatted = formatMessage(message, agentLabel)
     if (!formatted) {
         return null
     }
     return 'New message in session: ' + sessionId + '\n\n' + formatted
 }
 
-export function formatNewMessages(sessionId: string, messages: DecryptedMessage[]): string | null {
+export function formatNewMessages(sessionId: string, messages: DecryptedMessage[], agentLabel: string): string | null {
     const formatted = [...messages]
         .sort((a, b) => (a.seq ?? 0) - (b.seq ?? 0))
-        .map(formatMessage)
+        .map((m) => formatMessage(m, agentLabel))
         .filter(Boolean)
     if (formatted.length === 0) {
         return null
@@ -233,15 +240,15 @@ export function formatNewMessages(sessionId: string, messages: DecryptedMessage[
     return 'New messages in session: ' + sessionId + '\n\n' + formatted.join('\n\n')
 }
 
-export function formatHistory(sessionId: string, messages: DecryptedMessage[]): string {
+export function formatHistory(sessionId: string, messages: DecryptedMessage[], agentLabel: string): string {
     const messagesToFormat = VOICE_CONFIG.MAX_HISTORY_MESSAGES > 0
         ? messages.slice(-VOICE_CONFIG.MAX_HISTORY_MESSAGES)
         : messages
-    const formatted = messagesToFormat.map(formatMessage).filter(Boolean)
+    const formatted = messagesToFormat.map((m) => formatMessage(m, agentLabel)).filter(Boolean)
     return 'History of messages in session: ' + sessionId + '\n\n' + formatted.join('\n\n')
 }
 
-export function formatSessionFull(session: Session | null, messages: DecryptedMessage[]): string {
+export function formatSessionFull(session: Session | null, messages: DecryptedMessage[], agentLabel: string): string {
     if (!session) {
         return 'Session not available'
     }
@@ -262,7 +269,7 @@ export function formatSessionFull(session: Session | null, messages: DecryptedMe
 
     lines.push('## Our interaction history so far')
     lines.push('')
-    lines.push(formatHistory(session.id, messages))
+    lines.push(formatHistory(session.id, messages, agentLabel))
 
     return lines.join('\n\n')
 }
diff --git a/web/src/realtime/hooks/voiceContextPlan.test.ts b/web/src/realtime/hooks/voiceContextPlan.test.ts
index 3caf0bd7..bd315d2a 100644
--- a/web/src/realtime/hooks/voiceContextPlan.test.ts
+++ b/web/src/realtime/hooks/voiceContextPlan.test.ts
@@ -25,17 +25,18 @@ describe('buildSessionVoiceContextPlan', () => {
         const session = makeSession('sess-1')
         const messages = Array.from({ length: 10 }, (_, i) => makeMessage(i + 1, `line ${i + 1}`))
 
-        const plan = buildSessionVoiceContextPlan(session, messages)
+        const plan = buildSessionVoiceContextPlan(session, messages, 'Codex')
 
         expect(plan.bootstrap).toContain('sess-1')
         expect(plan.bootstrap).toContain('Auth refactor')
         expect(utf8ByteLength(plan.bootstrap)).toBeLessThanOrEqual(ELEVENLABS_WEBRTC_CONTEXT_MAX_BYTES)
         expect(plan.streamChunks.length).toBeGreaterThan(0)
         expect(plan.messagesInBootstrap).toBeLessThanOrEqual(2)
+        expect(plan.bootstrap).not.toContain('Claude Code')
     })
 
     test('handles missing session', () => {
-        const plan = buildSessionVoiceContextPlan(null, [])
+        const plan = buildSessionVoiceContextPlan(null, [], 'Claude')
         expect(plan.bootstrap).toBe('Session not available')
         expect(plan.streamChunks).toEqual([])
     })
diff --git a/web/src/realtime/hooks/voiceContextPlan.ts b/web/src/realtime/hooks/voiceContextPlan.ts
index 5ef0a7d9..fd160f4b 100644
--- a/web/src/realtime/hooks/voiceContextPlan.ts
+++ b/web/src/realtime/hooks/voiceContextPlan.ts
@@ -66,10 +66,14 @@ function chunkTextByBytes(parts: string[], maxBytes: number): string[] {
 
 /**
  * Small handshake context for startSession; remainder is streamed after connect.
+ *
+ * `agentLabel` is the display label for the session's agent flavor
+ * (e.g. "Claude", "Cursor", "Codex"); voiceHooks computes it once per call.
  */
 export function buildSessionVoiceContextPlan(
     session: Session | null,
-    messages: DecryptedMessage[]
+    messages: DecryptedMessage[],
+    agentLabel: string
 ): SessionVoiceContextPlan {
     if (!session) {
         return {
@@ -89,7 +93,7 @@ export function buildSessionVoiceContextPlan(
         : all
 
     const formatted = capped
-        .map((m) => formatMessage(m))
+        .map((m) => formatMessage(m, agentLabel))
         .filter((line): line is string => Boolean(line))
 
     const recentCount = Math.min(BOOTSTRAP_RECENT_MESSAGES, formatted.length)
diff --git a/web/src/realtime/hooks/voiceHooks.ts b/web/src/realtime/hooks/voiceHooks.ts
index 4c502559..203871f3 100644
--- a/web/src/realtime/hooks/voiceHooks.ts
+++ b/web/src/realtime/hooks/voiceHooks.ts
@@ -11,7 +11,8 @@ import {
 } from './contextFormatters'
 import { VOICE_CONFIG } from '../voiceConfig'
 import { buildSessionVoiceContextPlan, type SessionVoiceContextPlan } from './voiceContextPlan'
-import type { DecryptedMessage, Session } from '@/types/api'
+import { getFlavorLabel, isKnownFlavor } from '@hapi/protocol'
+import type { DecryptedMessage, Session, SessionMetadataSummary } from '@/types/api'
 
 interface SessionMetadata {
     summary?: { text?: string }
@@ -19,6 +20,17 @@ interface SessionMetadata {
     machineId?: string
 }
 
+/**
+ * Resolve the display label for the session's agent flavor. Falls back to a
+ * generic "coding agent" string for unknown or missing flavors so the voice
+ * context never bottoms out with a literal "undefined" or the old hardcoded
+ * "Claude Code" (closes #680).
+ */
+function getAgentLabel(session: Session | null): string {
+    const flavor = (session?.metadata as SessionMetadataSummary | undefined)?.flavor
+    return isKnownFlavor(flavor) ? getFlavorLabel(flavor) : 'coding agent'
+}
+
 // Track which sessions have been reported
 const shownSessions = new Set<string>()
 let lastFocusSession: string | null = null
@@ -66,7 +78,7 @@ function reportSession(sessionId: string) {
     if (!session) return
 
     const messages = messagesGetter?.(sessionId) ?? []
-    const contextUpdate = formatSessionFull(session, messages)
+    const contextUpdate = formatSessionFull(session, messages, getAgentLabel(session))
     reportContextualUpdate(contextUpdate)
 }
 
@@ -106,13 +118,14 @@ export const voiceHooks = {
     },
 
     /**
-     * Called when Claude requests permission for a tool use
+     * Called when the active agent requests permission for a tool use
      */
     onPermissionRequested(sessionId: string, requestId: string, toolName: string, toolArgs: unknown) {
         if (VOICE_CONFIG.DISABLE_PERMISSION_REQUESTS) return
 
+        const session = sessionGetter?.(sessionId) ?? null
         reportSession(sessionId)
-        reportTextUpdate(formatPermissionRequest(sessionId, requestId, toolName, toolArgs))
+        reportTextUpdate(formatPermissionRequest(sessionId, requestId, toolName, toolArgs, getAgentLabel(session)))
     },
 
     /**
@@ -121,8 +134,9 @@ export const voiceHooks = {
     onMessages(sessionId: string, messages: DecryptedMessage[]) {
         if (VOICE_CONFIG.DISABLE_MESSAGES) return
 
+        const session = sessionGetter?.(sessionId) ?? null
         reportSession(sessionId)
-        reportContextualUpdate(formatNewMessages(sessionId, messages))
+        reportContextualUpdate(formatNewMessages(sessionId, messages, getAgentLabel(session)))
     },
 
     /**
@@ -136,7 +150,7 @@ export const voiceHooks = {
 
         const session = sessionGetter?.(sessionId) ?? null
         const messages = messagesGetter?.(sessionId) ?? []
-        const plan = buildSessionVoiceContextPlan(session, messages)
+        const plan = buildSessionVoiceContextPlan(session, messages, getAgentLabel(session))
         shownSessions.add(sessionId)
         return plan
     },