diff --git a/src/main/index.ts b/src/main/index.ts
index 9278eb043..312b8bfd9 100644
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -1766,7 +1766,11 @@ app.whenReady().then(async () => {
     }
   )
   electronApp.setAppUserModelId(devInstanceIdentity.appUserModelId)
-  app.setName(devInstanceIdentity.name)
+  // Why: setName drives the macOS safeStorage Keychain item name. Use the stable
+  // appName (not the per-branch `name`) so dev branches share one key and don't
+  // re-prompt per branch; the per-branch label still shows via window title,
+  // renderer identity, and the app-menu label passed to registerAppMenu below.
+  app.setName(devInstanceIdentity.appName)
 
   // Why: managed WSL launchers live outside the Windows app bundle, so keep
   // their launcher and bridge contract synchronized across app updates.
@@ -2138,6 +2142,7 @@ app.whenReady().then(async () => {
   logStartupMilestone('i18n-ready')
 
   registerAppMenu({
+    appMenuLabel: devInstanceIdentity.name,
     onCheckForUpdates: (options) => runUserInitiatedUpdateCheck(options),
     onBeforeReload: ({ ignoreCache, webContentsId }) => {
       if (mainWindow?.webContents.id === webContentsId) {
diff --git a/src/main/menu/register-app-menu.ts b/src/main/menu/register-app-menu.ts
index c36aca697..2f3a3d70a 100644
--- a/src/main/menu/register-app-menu.ts
+++ b/src/main/menu/register-app-menu.ts
@@ -37,6 +37,9 @@ type RegisterAppMenuOptions = {
   onToggleAppearance: (key: AppearanceMenuKey) => void
   getAppearanceState: () => AppearanceMenuState
   getKeybindings?: () => KeybindingOverrides | undefined
+  // Why: the macOS app-menu title. Passed the per-branch dev label since
+  // app.name is now pinned to a stable value for Keychain-key stability.
+  appMenuLabel?: string
 }
 
 function buildAndApplyMenu(options: RegisterAppMenuOptions): void {
@@ -130,7 +133,7 @@ function buildAndApplyMenu(options: RegisterAppMenuOptions): void {
   // redundant "Orca" entry with roles that don't apply, so we omit it there
   // and distribute its items across File / Help instead.
   const macAppMenu: Electron.MenuItemConstructorOptions = {
-    label: app.name,
+    label: options.appMenuLabel ?? app.name,
     submenu: [
       { role: 'about' },
       checkForUpdatesItem,
diff --git a/src/main/startup/dev-instance-identity.test.ts b/src/main/startup/dev-instance-identity.test.ts
index 2021dfed2..2b06e85dd 100644
--- a/src/main/startup/dev-instance-identity.test.ts
+++ b/src/main/startup/dev-instance-identity.test.ts
@@ -5,6 +5,7 @@ describe('dev-instance-identity', () => {
   it('keeps packaged identity stable', () => {
     expect(getDevInstanceIdentity(false, {})).toMatchObject({
       name: 'Orca',
+      appName: 'Orca',
       isDev: false,
       devLabel: null,
       dockBadgeLabel: null,
@@ -12,6 +13,18 @@ describe('dev-instance-identity', () => {
     })
   })
 
+  it('pins a stable dev appName across branches so the safeStorage key does not churn', () => {
+    const a = getDevInstanceIdentity(true, { ORCA_DEV_BRANCH: 'feature/a' })
+    const b = getDevInstanceIdentity(true, { ORCA_DEV_BRANCH: 'feature/b' })
+
+    // Per-branch label differs (window title / app menu)...
+    expect(a.name).not.toBe(b.name)
+    // ...but the Keychain-driving appName is identical and distinct from prod.
+    expect(a.appName).toBe('Orca Dev')
+    expect(b.appName).toBe('Orca Dev')
+    expect(a.appName).not.toBe('Orca')
+  })
+
   it('derives a readable dev label from worktree and branch env', () => {
     const identity = getDevInstanceIdentity(true, {
       ORCA_DEV_REPO_ROOT: '/repo/worktrees/dev-indicator',
diff --git a/src/main/startup/dev-instance-identity.ts b/src/main/startup/dev-instance-identity.ts
index b375e88bb..6d13541ea 100644
--- a/src/main/startup/dev-instance-identity.ts
+++ b/src/main/startup/dev-instance-identity.ts
@@ -8,6 +8,11 @@ const MAX_LABEL_LENGTH = 80
 
 export type DevInstanceIdentity = AppIdentity & {
   appUserModelId: string
+  // Why: drives app.setName → the macOS safeStorage Keychain item name
+  // ("<appName> Safe Storage"). Kept stable across dev branches (unlike the
+  // per-branch `name`) so every dev instance shares one Keychain key instead of
+  // creating a new one per branch and re-prompting. Distinct from prod's 'Orca'.
+  appName: string
 }
 
 function cleanEnvValue(value: string | undefined): string | null {
@@ -50,6 +55,7 @@ export function getDevInstanceIdentity(
   if (!isDev) {
     return {
       name: BASE_APP_NAME,
+      appName: BASE_APP_NAME,
       isDev: false,
       devLabel: null,
       devBranch: null,
@@ -71,6 +77,10 @@ export function getDevInstanceIdentity(
 
   return {
     name: dockTitle,
+    // Why: one stable Keychain key ('Orca Dev Safe Storage') for all dev
+    // branches; the per-branch identity still shows via `name` (window title,
+    // app menu, renderer label).
+    appName: `${BASE_APP_NAME} Dev`,
     isDev: true,
     devLabel,
     devBranch: branch,