agent-signals

053. Codex CLI on Windows ignores USERPROFILE and HOME

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Date
2026-10-30
Agents
Codex 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 codex codex in the scenarios workflow (run 41146500448, and again in run 41145363320), Codex CLI 0.166.0 from npm @openai/codex. The driver set USERPROFILE, HOME, HOMEDRIVE, HOMEPATH, APPDATA, LOCALAPPDATA, TEMP and TMP to folders in a throwaway folder for the agent. It listed the real profile folders (USERPROFILE and APPDATA to two levels, LOCALAPPDATA to two levels without Temp, and TEMP to one level) before the start, and again after 5 s and after 20 s.

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

What was measured

  1. Codex CLI made no file in the throwaway home on the three images.
  2. On the three images, Codex CLI made these entries in the real %USERPROFILE%\.codex after 5 s, and they were the same after 20 s: config.toml, installation_id, version.json, .sandbox, .tmp, skills, and the SQLite files state_5, logs_2, goals_1, memories_1 and queue_1, each with -wal and -shm. These are the same names as in ~/.codex on Linux (fact 29).
  3. Its screen was the normal first screen (fact 52). The processes were node codex.js and codex.exe (fact 51).
  4. Each other agent of fact 51 that started made its own files in the throwaway home. Amp on windows-11-arm and Factory Droid in run 41146500448 did not start (fact 51).

Mechanism

codex.exe is a Rust program. A Rust program that asks Windows for the profile folder (for example with SHGetKnownFolderPath) does not read USERPROFILE or HOME. This was not checked in the source. CODEX_HOME was not set. Codex CLI has the variable CODEX_HOME for the folder of ~/.codex. It was not tested here.

A scenario on Windows that must not touch the real profile must set CODEX_HOME for Codex CLI. A tool that looks for the Codex files of a Windows user must look in the profile folder of the account, not in a folder from the environment of the process.

Incident

The first-run scenario wrote a Codex state into the real profile of each runner. The runner is thrown away after the job, so this did no harm in CI. On a real machine, the same scenario would add files to the user's .codex folder.

Screens

None.

Not measured