diff --git a/cli/src/modules/common/rpcTypes.ts b/cli/src/modules/common/rpcTypes.ts
index 6336f57d..5e243eb8 100644
--- a/cli/src/modules/common/rpcTypes.ts
+++ b/cli/src/modules/common/rpcTypes.ts
@@ -1,10 +1,12 @@
+import type { AgentFlavor } from '@hapi/protocol'
+
 export interface SpawnSessionOptions {
     machineId?: string
     directory: string
     sessionId?: string
     resumeSessionId?: string
     approvedNewDirectoryCreation?: boolean
-    agent?: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode'
+    agent?: AgentFlavor
     model?: string
     effort?: string
     modelReasoningEffort?: string
diff --git a/hub/src/sync/rpcGateway.ts b/hub/src/sync/rpcGateway.ts
index 882d87c5..a13fb2e5 100644
--- a/hub/src/sync/rpcGateway.ts
+++ b/hub/src/sync/rpcGateway.ts
@@ -1,4 +1,4 @@
-import type { CodexCollaborationMode, PermissionMode } from '@hapi/protocol/types'
+import type { AgentFlavor, CodexCollaborationMode, PermissionMode } from '@hapi/protocol/types'
 import type { Server } from 'socket.io'
 import type { RpcRegistry } from '../socket/rpcRegistry'
 
@@ -150,7 +150,7 @@ export class RpcGateway {
     async spawnSession(
         machineId: string,
         directory: string,
-        agent: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode' = 'claude',
+        agent: AgentFlavor = 'claude',
         model?: string,
         modelReasoningEffort?: string,
         yolo?: boolean,
diff --git a/hub/src/sync/syncEngine.ts b/hub/src/sync/syncEngine.ts
index 76d56e73..166691fc 100644
--- a/hub/src/sync/syncEngine.ts
+++ b/hub/src/sync/syncEngine.ts
@@ -7,7 +7,7 @@
  * - No E2E encryption; data is stored as JSON in SQLite
  */
 
-import type { LocalResumeTarget, ResumableSession } from '@hapi/protocol'
+import { isKnownFlavor, type LocalResumeTarget, type ResumableSession } from '@hapi/protocol'
 import type { AgentFlavor, CodexCollaborationMode, DecryptedMessage, PermissionMode, Session, SyncEvent } from '@hapi/protocol/types'
 import { unwrapRoleWrappedRecordEnvelope } from '@hapi/protocol/messages'
 import type { Server } from 'socket.io'
@@ -459,7 +459,7 @@ export class SyncEngine {
     async spawnSession(
         machineId: string,
         directory: string,
-        agent: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode' = 'claude',
+        agent: AgentFlavor = 'claude',
         model?: string,
         modelReasoningEffort?: string,
         yolo?: boolean,
@@ -486,9 +486,7 @@ export class SyncEngine {
 
     private resolveFlavor(session: Session): AgentFlavor {
         const flavor = session.metadata?.flavor
-        return flavor === 'codex' || flavor === 'gemini' || flavor === 'opencode' || flavor === 'cursor'
-            ? flavor
-            : 'claude'
+        return isKnownFlavor(flavor) ? flavor : 'claude'
     }
 
     private resolveAgentResumeId(session: Session, namespace: string): string | null {
diff --git a/hub/src/web/routes/machines.ts b/hub/src/web/routes/machines.ts
index 9f201fbe..7bd65eea 100644
--- a/hub/src/web/routes/machines.ts
+++ b/hub/src/web/routes/machines.ts
@@ -1,3 +1,4 @@
+import { AgentFlavorSchema } from '@hapi/protocol'
 import { Hono } from 'hono'
 import { z } from 'zod'
 import type { SyncEngine } from '../../sync/syncEngine'
@@ -6,7 +7,7 @@ import { requireMachine } from './guards'
 
 const spawnBodySchema = z.object({
     directory: z.string().min(1),
-    agent: z.enum(['claude', 'codex', 'cursor', 'gemini', 'opencode']).optional(),
+    agent: AgentFlavorSchema.optional(),
     model: z.string().optional(),
     effort: z.string().optional(),
     modelReasoningEffort: z.string().optional(),
diff --git a/shared/src/modes.ts b/shared/src/modes.ts
index d59320a9..ac6a04df 100644
--- a/shared/src/modes.ts
+++ b/shared/src/modes.ts
@@ -1,3 +1,5 @@
+import { z } from 'zod'
+
 /**
  * @description The legacy payload type identifier used for all generic agent messages.
  * Changing this value will affect the communication schema between CLI, Hub, and Web.
@@ -5,6 +7,10 @@
  */
 export const AGENT_MESSAGE_PAYLOAD_TYPE = 'codex' as const
 
+export const AGENT_FLAVORS = ['claude', 'codex', 'cursor', 'gemini', 'opencode'] as const
+export type AgentFlavor = typeof AGENT_FLAVORS[number]
+export const AgentFlavorSchema = z.enum(AGENT_FLAVORS)
+
 export const CLAUDE_PERMISSION_MODES = ['default', 'acceptEdits', 'bypassPermissions', 'plan'] as const
 export type ClaudePermissionMode = typeof CLAUDE_PERMISSION_MODES[number]
 
@@ -35,8 +41,6 @@ export const PERMISSION_MODES = [
 ] as const
 export type PermissionMode = typeof PERMISSION_MODES[number]
 
-export type AgentFlavor = 'claude' | 'codex' | 'gemini' | 'opencode' | 'cursor'
-
 export const PERMISSION_MODE_LABELS: Record<PermissionMode, string> = {
     default: 'Default',
     acceptEdits: 'Accept Edits',
diff --git a/shared/src/resume.ts b/shared/src/resume.ts
index d5cbe8eb..4c75c2cd 100644
--- a/shared/src/resume.ts
+++ b/shared/src/resume.ts
@@ -1,7 +1,6 @@
 import { z } from 'zod'
 import { CodexCollaborationModeSchema, PermissionModeSchema } from './schemas'
-
-export const AgentFlavorSchema = z.enum(['claude', 'codex', 'gemini', 'opencode', 'cursor'])
+import { AgentFlavorSchema } from './modes'
 
 export const LocalResumeTargetSchema = z.object({
     sessionId: z.string().min(1),
diff --git a/web/src/api/client.ts b/web/src/api/client.ts
index 4b15aab7..883e555a 100644
--- a/web/src/api/client.ts
+++ b/web/src/api/client.ts
@@ -25,6 +25,7 @@ import type {
     SessionResponse,
     SessionsResponse
 } from '@/types/api'
+import type { AgentFlavor } from '@hapi/protocol'
 import type { CancelMessageResponse } from '@hapi/protocol/schemas'
 
 type ApiClientOptions = {
@@ -459,7 +460,7 @@ export class ApiClient {
     async spawnSession(
         machineId: string,
         directory: string,
-        agent?: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode',
+        agent?: AgentFlavor,
         model?: string,
         modelReasoningEffort?: string,
         yolo?: boolean,
diff --git a/web/src/components/NewSession/AgentSelector.tsx b/web/src/components/NewSession/AgentSelector.tsx
index 73e87d46..4146f308 100644
--- a/web/src/components/NewSession/AgentSelector.tsx
+++ b/web/src/components/NewSession/AgentSelector.tsx
@@ -1,3 +1,4 @@
+import { AGENT_FLAVORS } from '@hapi/protocol'
 import type { AgentType } from './types'
 import { useTranslation } from '@/lib/use-translation'
 
@@ -14,7 +15,7 @@ export function AgentSelector(props: {
                 {t('newSession.agent')}
             </label>
             <div className="flex flex-wrap gap-x-3 gap-y-2">
-                {(['claude', 'codex', 'cursor', 'gemini', 'opencode'] as const).map((agentType) => (
+                {AGENT_FLAVORS.map((agentType) => (
                     <label
                         key={agentType}
                         className="flex items-center gap-1.5 cursor-pointer"
diff --git a/web/src/components/NewSession/preferences.ts b/web/src/components/NewSession/preferences.ts
index 84ac458f..0f8fe42a 100644
--- a/web/src/components/NewSession/preferences.ts
+++ b/web/src/components/NewSession/preferences.ts
@@ -1,9 +1,10 @@
+import { AGENT_FLAVORS } from '@hapi/protocol'
 import type { AgentType } from './types'
 
 const AGENT_STORAGE_KEY = 'hapi:newSession:agent'
 const YOLO_STORAGE_KEY = 'hapi:newSession:yolo'
 
-const VALID_AGENTS: AgentType[] = ['claude', 'codex', 'cursor', 'gemini', 'opencode']
+const VALID_AGENTS = AGENT_FLAVORS
 
 export function loadPreferredAgent(): AgentType {
     try {
diff --git a/web/src/components/NewSession/types.ts b/web/src/components/NewSession/types.ts
index a950a6ff..d7a1533d 100644
--- a/web/src/components/NewSession/types.ts
+++ b/web/src/components/NewSession/types.ts
@@ -1,6 +1,7 @@
 import { GEMINI_MODEL_PRESETS, GEMINI_MODEL_LABELS } from '@hapi/protocol'
+import type { AgentFlavor } from '@hapi/protocol'
 
-export type AgentType = 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode'
+export type AgentType = AgentFlavor
 export type SessionType = 'simple' | 'worktree'
 export type CodexReasoningEffort = 'default' | 'low' | 'medium' | 'high' | 'xhigh'
 export type ClaudeEffort = 'auto' | 'medium' | 'high' | 'max'
diff --git a/web/src/hooks/mutations/useSpawnSession.ts b/web/src/hooks/mutations/useSpawnSession.ts
index 37f69f61..bf61825f 100644
--- a/web/src/hooks/mutations/useSpawnSession.ts
+++ b/web/src/hooks/mutations/useSpawnSession.ts
@@ -1,4 +1,5 @@
 import { useMutation, useQueryClient } from '@tanstack/react-query'
+import type { AgentFlavor } from '@hapi/protocol'
 import type { ApiClient } from '@/api/client'
 import type { SpawnResponse } from '@/types/api'
 import { queryKeys } from '@/lib/query-keys'
@@ -6,7 +7,7 @@ import { queryKeys } from '@/lib/query-keys'
 type SpawnInput = {
     machineId: string
     directory: string
-    agent?: 'claude' | 'codex' | 'cursor' | 'gemini' | 'opencode'
+    agent?: AgentFlavor
     model?: string
     effort?: string
     modelReasoningEffort?: string