[BUG] cowork-svc repeatedly re-verifies claude.exe signature on every RPC call, causing ~195MB/s I/O

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

cowork-svc.exe repeatedly re-verifies the cryptographic signature of claude.exe (213MB) on every single RPC call, rather than caching the result. Because something is polling via isGuestConnected and isProcessRunning every ~2 seconds, this causes a sustained ~195MB/s of disk reads in a continuous cycle for the entire duration the app is open.The session is declared idle after each cycle, suggesting the client is not maintaining a persistent connection — it reconnects fresh each time, which forces a full re-verification on every call. Observed in ProcExp: cowork-svc.exe (PID 9376), R: 195MB, W: 1.2KB — almost entirely reads. Private bytes only 36MB on a 128GB RAM machine, ruling out memory pressure/paging as the cause.

<img width="758" height="531" alt="Image" src="https://github.com/user-attachments/assets/3e891abb-b016-481c-97de-82d485436ba2" />

<img width="1568" height="690" alt="Image" src="https://github.com/user-attachments/assets/1a6d5a04-b31b-4c84-b93d-c94f3033311f" />

What Should Happen?

Signature verification of claude.exe should be performed once on first connection and the result cached for the lifetime of the session. Subsequent RPC calls should reuse the cached verification result. The ~2 second polling cycle should not trigger a full 213MB binary read on every iteration.

Error Messages/Logs

2026/03/06 01:14:32.166127 [Server] Received request: method=isGuestConnected
2026/03/06 01:14:32.315230 [Server] Client signature verified: C:\Program Files\WindowsApps\Claude_1.1.4498.0_x64__pzs8sxrjxfjjc\app\claude.exe (subject: Anthropic, PBC)
2026/03/06 01:14:32.315230 [Server] Sent response: success=true
2026/03/06 01:14:32.315752 [Server] Client connected
2026/03/06 01:14:32.315752 [Server] Received request: method=isProcessRunning
2026/03/06 01:14:32.463242 [Server] Client signature verified: C:\Program Files\WindowsApps\Claude_1.1.4498.0_x64__pzs8sxrjxfjjc\app\claude.exe (subject: Anthropic, PBC)
2026/03/06 01:14:32.463745 [RPC] Sending request: method=isRunning id=req-916 (waiting for response)
2026/03/06 01:14:32.464272 [Server] Sent response: success=true
2026/03/06 01:14:32.464272 [Server] Session Rob:...\Claude has no active connections, idle timeout starts
2026/03/06 01:14:34.179314 [Server] Client connected
2026/03/06 01:14:34.179314 [Server] Received request: method=isGuestConnected
2026/03/06 01:14:34.327333 [Server] Client signature verified: C:\Program Files\WindowsApps\Claude_1.1.4498.0_x64__pzs8sxrjxfjjc\app\claude.exe (subject: Anthropic, PBC)
2026/03/06 01:14:34.327333 [Server] Sent response: success=true
2026/03/06 01:14:34.327333 [Server] Client connected
2026/03/06 01:14:34.327860 [Server] Received request: method=isProcessRunning
2026/03/06 01:14:34.475298 [Server] Client signature verified: C:\Program Files\WindowsApps\Claude_1.1.4498.0_x64__pzs8sxrjxfjjc\app\claude.exe (subject: Anthropic, PBC)
2026/03/06 01:14:34.475298 [RPC] Sending request: method=isRunning id=req-917 (waiting for response)
2026/03/06 01:14:34.475824 [Server] Sent response: success=true
2026/03/06 01:14:34.475824 [Server] Session Rob:...\Claude has no active connections, idle timeout starts

Steps to Reproduce

Run Claude Desktop.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.1.5368 (d12d02) 2026-03-05T17:29:33.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_