fix: address pr-bug-scan validated finding from #7862

Oversized Hermes automation prompts no longer fail: launcher falls back to launching 'hermes --tui' empty and pasting the prompt after ready, so buildAgentStartupPlan-null no longer returns null.

src/renderer/src/lib/launch-agent-background-session.test.ts

@@ -516,6 +516,27 @@ describe('launchAgentBackgroundSession', () => {
     expect(mockPasteDraftWhenAgentReady).not.toHaveBeenCalled()
   })
 
+  it('falls back to paste delivery when a Hermes prompt overflows the startup-query budget', async () => {
+    const oversizedPrompt = 'x'.repeat(30_000)
+    const { launchAgentBackgroundSession } = await import('./launch-agent-background-session')
+
+    const result = await launchAgentBackgroundSession({
+      agent: 'hermes',
+      worktreeId: 'wt-1',
+      prompt: oversizedPrompt
+    })
+
+    expect(result).not.toBeNull()
+    expect(mockSpawn).toHaveBeenCalledWith(
+      expect.objectContaining({ command: 'hermes --tui' })
+    )
+    const spawnArgs = mockSpawn.mock.calls[0]?.[0]
+    expect(spawnArgs?.env?.ORCA_HERMES_STARTUP_QUERY).toBeUndefined()
+    expect(mockPasteDraftWhenAgentReady).toHaveBeenCalledWith(
+      expect.objectContaining({ agent: 'hermes', content: oversizedPrompt, submit: true })
+    )
+  })
+
   it('uses the configured cmd shell for Windows Hermes background launches', async () => {
     mockGetAgentLaunchPlatformForRepo.mockReturnValue('win32')
     Object.assign(state.settings, { terminalWindowsShell: 'cmd.exe' })

src/renderer/src/lib/launch-agent-background-session.ts

@@ -83,8 +83,8 @@ export async function launchAgentBackgroundSession(
   const hasPrompt = trimmedPrompt.length > 0
   const isFollowupPath = TUI_AGENT_CONFIG[agent].promptInjectionMode === 'stdin-after-start'
 
-  const pasteDraftAfterLaunch = hasPrompt && isFollowupPath ? trimmedPrompt : null
-  const startupPlan = buildAgentStartupPlan({
+  let pasteDraftAfterLaunch = hasPrompt && isFollowupPath ? trimmedPrompt : null
+  let startupPlan = buildAgentStartupPlan({
     agent,
     prompt: hasPrompt && !isFollowupPath ? trimmedPrompt : '',
     cmdOverrides,
@@ -95,6 +95,26 @@ export async function launchAgentBackgroundSession(
     isRemote,
     allowEmptyPromptLaunch: !hasPrompt || isFollowupPath
   })
+  if (!startupPlan && hasPrompt && !isFollowupPath) {
+    // Why: a large prompt (e.g. an automation PR diff) can overflow the Hermes
+    // native startup-query env budget, making buildAgentStartupPlan return null.
+    // Rather than fail the whole dispatch, launch the agent with no prompt and
+    // paste it after the TUI is ready — the pre-native-query delivery path.
+    startupPlan = buildAgentStartupPlan({
+      agent,
+      prompt: '',
+      cmdOverrides,
+      agentArgs,
+      agentEnv,
+      platform: launchPlatform,
+      shell: startupShell,
+      isRemote,
+      allowEmptyPromptLaunch: true
+    })
+    if (startupPlan) {
+      pasteDraftAfterLaunch = trimmedPrompt
+    }
+  }
   if (!startupPlan) {
     return null
   }