Resume does not restore the same project context as a fresh session in WSL (project-local MCP/skills diverge, `$` skill picker becomes empty)

[Wool-yang]

What version of Codex CLI is running?

0.120.0

What subscription do you have?

Paid ChatGPT plan (exact tier omitted for privacy)

Which model were you using?

gpt-5.4 xhigh

What platform is your computer?

WSL on Windows; workspace located on a mounted /mnt//... path

What terminal emulator and version are you using (if applicable)?

WSL terminal (exact emulator/version omitted for privacy)

What issue are you seeing?

In a WSL workspace on a mounted Windows drive, resuming an old Codex session does not restore the same effective project context as starting a fresh session in the same directory.

The most visible symptoms are:

• project-local MCP behavior diverges from a fresh session
• the $ skill picker in the TUI becomes empty after resuming an older session
• a fresh session in the same workspace still shows system skills normally
• explicit skill invocation can still work even when the $ picker is empty

This appears to be resume-specific state restoration behavior rather than a missing config or missing skill file on disk.

What steps can reproduce the bug?

1. Use Codex CLI from WSL in a repository stored on a mounted Windows drive, for example under /mnt/<drive>/Program/<repo>.

2. Add a project-local .codex/config.toml with at least one project-local MCP server.

3. Optionally add a project-local skill under .codex/skills/<name>/SKILL.md.

4. Start a fresh Codex TUI session in that workspace.

5. Verify that fresh-session behavior is correct:

   • $ shows the usual system skills
   • project-local MCP is available

6. Exit Codex.

7. Resume an older session for the same workspace.

8. Press $ again and compare with the fresh session.

Observed result in the resumed session:

• the $ skill picker can be empty
• project-local context is not equivalent to a fresh session in the same workspace

What is the expected behavior?

A resumed session should restore the same effective workspace-derived behavior as a fresh session started in that same directory.

That includes:

• the same project-local MCP availability
• the same system/project skill visibility in $
• the same effective config derived from the workspace
• no observable UX difference between fresh session and resumed session for the same project

Additional information

Additional findings from local investigation:

• The workspace itself is valid: a fresh session in the same directory behaves correctly.
• The issue is specific to resume behavior.
• Explicit skill invocation can still work even when the $ picker is empty, which suggests a UI/session-state mismatch rather than "skills do not exist".
• The problem reproduces in a WSL workspace on /mnt/....
• Investigation strongly suggests fresh-session initialization and resumed-session initialization are not restoring the same project-derived runtime state.

Possible root-cause direction:

• resume may be reusing an already-running thread/session state and not fully rebuilding workspace-derived config, skill state, and project-local MCP state the same way fresh startup does.

Privacy note:

• exact repo name, drive letter, terminal brand/version, and subscription tier are intentionally omitted here.

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• Resumed threads keep stale model-visible skills after new skills are added #16607
• WSL resume can lower-case session cwd (/mnt/...) and make Codex switch path spelling mid-session #16690

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[Wool-yang]

Clarification on the path-related part of this bug:I am using Codex from inside WSL, not from a native Windows terminal.The path pattern involved here is:- expected / original workspace path in WSL: /mnt/<drive>/Program/<repo>- path spelling that can appear after resume: /mnt/<drive>/program/<repo>So the case change is happening in the WSL /mnt/... path space.If it helps to map this to the host filesystem, this corresponds conceptually to a Windows-side location like <Drive>:\Program\<repo>.The important point is that the bug is observed while using the Codex CLI/TUI from WSL, and the path-case change in the WSL path appears to interact with project-local config / MCP / skill restoration after resume.Privacy note: I am intentionally not including the exact repository name or exact local path.