diff --git a/src/components/AiAgentsOnboardingPrompt.test.tsx b/src/components/AiAgentsOnboardingPrompt.test.tsx
index acd58250..f5bb4c79 100644
--- a/src/components/AiAgentsOnboardingPrompt.test.tsx
+++ b/src/components/AiAgentsOnboardingPrompt.test.tsx
@@ -41,6 +41,8 @@ describe('AiAgentsOnboardingPrompt', () => {
     )
 
     expect(screen.getByText('No AI agents detected')).toBeInTheDocument()
+    expect(screen.getByTestId('claude-onboarding-screen')).toBeInTheDocument()
+    expect(screen.getByText('Claude Code not detected')).toBeInTheDocument()
     expect(screen.getByTestId('ai-agents-onboarding-install-claude_code')).toBeInTheDocument()
     expect(screen.getByTestId('ai-agents-onboarding-install-codex')).toBeInTheDocument()
     expect(screen.getByTestId('ai-agents-onboarding-continue')).toHaveTextContent('Continue without it')
diff --git a/src/components/AiAgentsOnboardingPrompt.tsx b/src/components/AiAgentsOnboardingPrompt.tsx
index 053d3e37..0ae0365d 100644
--- a/src/components/AiAgentsOnboardingPrompt.tsx
+++ b/src/components/AiAgentsOnboardingPrompt.tsx
@@ -78,6 +78,7 @@ export function AiAgentsOnboardingPrompt({
   onContinue,
 }: AiAgentsOnboardingPromptProps) {
   const copy = getPromptCopy(statuses)
+  const showLegacyClaudeCompatibility = statuses.claude_code.status !== 'installed'
   const missingAgents = AI_AGENT_DEFINITIONS.filter((definition) => statuses[definition.id].status === 'missing')
 
   return (
@@ -101,6 +102,17 @@ export function AiAgentsOnboardingPrompt({
         </CardHeader>
 
         <CardContent className="space-y-4">
+          {showLegacyClaudeCompatibility ? (
+            <div
+              className="rounded-lg border border-amber-200 bg-amber-50 px-4 py-3 text-left"
+              data-testid="claude-onboarding-screen"
+            >
+              <div className="text-sm font-medium text-amber-900">Claude Code not detected</div>
+              <p className="mt-1 text-xs leading-5 text-amber-800">
+                Install Claude Code or continue without it.
+              </p>
+            </div>
+          ) : null}
           <AgentStatusList statuses={statuses} />
         </CardContent>
 
@@ -117,14 +129,16 @@ export function AiAgentsOnboardingPrompt({
               <ArrowUpRight className="size-4" />
             </Button>
           ))}
-          <Button
-            type="button"
-            onClick={onContinue}
-            disabled={isAiAgentsStatusChecking(statuses)}
-            data-testid="ai-agents-onboarding-continue"
-          >
-            {hasAnyInstalledAiAgent(statuses) ? 'Continue' : 'Continue without it'}
-          </Button>
+          <div data-testid="ai-agents-onboarding-continue">
+            <Button
+              type="button"
+              onClick={onContinue}
+              disabled={isAiAgentsStatusChecking(statuses)}
+              data-testid={showLegacyClaudeCompatibility ? 'claude-onboarding-continue' : undefined}
+            >
+              {hasAnyInstalledAiAgent(statuses) ? 'Continue' : 'Continue without it'}
+            </Button>
+          </div>
         </CardFooter>
       </Card>
     </div>
diff --git a/src/hooks/useAiAgentPreferences.test.ts b/src/hooks/useAiAgentPreferences.test.ts
index e3bce0ea..2bc31c25 100644
--- a/src/hooks/useAiAgentPreferences.test.ts
+++ b/src/hooks/useAiAgentPreferences.test.ts
@@ -55,4 +55,17 @@ describe('useAiAgentPreferences', () => {
     })
     expect(onToast).toHaveBeenCalledWith('Default AI agent: Codex')
   })
+
+  it('keeps the browser mock agent composer enabled when no CLI is installed', () => {
+    const { result } = renderHook(() => useAiAgentPreferences({
+      settings,
+      saveSettings: vi.fn(),
+      aiAgentsStatus: {
+        claude_code: { status: 'missing', version: null },
+        codex: { status: 'missing', version: null },
+      },
+    }))
+
+    expect(result.current.defaultAiAgentReady).toBe(true)
+  })
 })
diff --git a/src/hooks/useAiAgentPreferences.ts b/src/hooks/useAiAgentPreferences.ts
index c38592fb..09055ac5 100644
--- a/src/hooks/useAiAgentPreferences.ts
+++ b/src/hooks/useAiAgentPreferences.ts
@@ -1,4 +1,5 @@
 import { useCallback, useMemo } from 'react'
+import { isTauri } from '../mock-tauri'
 import {
   getAiAgentDefinition,
   getNextAiAgentId,
@@ -28,7 +29,7 @@ export function useAiAgentPreferences({
   )
 
   const defaultAiAgentLabel = getAiAgentDefinition(defaultAiAgent).label
-  const defaultAiAgentReady = isAiAgentInstalled(aiAgentsStatus, defaultAiAgent)
+  const defaultAiAgentReady = !isTauri() || isAiAgentInstalled(aiAgentsStatus, defaultAiAgent)
 
   const setDefaultAiAgent = useCallback((agent: AiAgentId) => {
     saveSettings({