agent-signals

054. Cursor CLI on Windows uses the account name of Windows and its install folder

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Date
2026-10-30
Agents
Cursor CLI
Measured on
CI runner windows-2022 (x64), CI runner windows-2025 (x64) and CI runner windows-11-arm (arm64)

Measured

2026-10-30, the scenario scenarios/first-run-windows.py cursor cursor-agent in the scenarios workflow (run 41146500448, and again in run 41145363320), Cursor CLI 2026.10.22-27dcf5f from irm 'https://cursor.com/install?win32=true' | iex. The driver set the throwaway profile of fact 53 and USERNAME=dev. It logged each file path below the throwaway home that held the real account name, and the changes in the real profile folders.

Measured on: CI runner windows-2022 (x64), CI runner windows-2025 (x64) and CI runner windows-11-arm (arm64).

What was measured

  1. Cursor CLI made .cursor\agent-cli-state.json, cli-config.json and statsig-cache.json in the throwaway home, the same files as on Linux (fact 29). It reads USERPROFILE for these.
  2. It made a log AppData\Local\Temp\cursor-agent-logs-<account>\session-<time>-<pid>-1.log in the throwaway TEMP, and held it open. <account> was the account name of Windows, not the USERNAME value dev. The driver logged "2 paths below the throwaway home hold the Windows account name" at 5 s and at 20 s on the three images (run 41146500448).
  3. In the real profile, the folder %LOCALAPPDATA%\cursor-agent\versions changed on the three images. This is the install folder. The .cmd shim starts powershell.exe -NoProfile -ExecutionPolicy Bypass -File with a script in that folder, and the script starts versions\<version>\node.exe (fact 51).
  4. In run 41145363320, the real %USERPROFILE%\.cursor also changed on windows-2025 and windows-11-arm. In run 41146500448, it did not change.

Mechanism

The shim finds the install from its own path, not from LOCALAPPDATA, so the agent starts also when LOCALAPPDATA points elsewhere. The account name probably comes from os.userInfo() of Node.js, which asks Windows and not the environment. This was not checked in the source.

The .cursor change in run 41145363320 can come from the --version call, which ran with the real profile before the start. This was not checked.

A tool that wants the log folder of a Cursor CLI session on Windows must use the account name of the process, not USERNAME.

Incident

The account name of the runner showed in a CI log of an earlier run of this scenario (run 41144210399, now deleted). The scrub did not find it, because a - before the name is a word character for the scrub's account rule. The driver now replaces the account name in each file that it writes.

Screens

None.

Not measured