Pass workspace directory to MCP servers

[ginishuh]

Summary

The Codex VS Code extension spawns MCP servers from the VS Code installation directory instead of the workspace directory. This fundamentally breaks semantic code analysis tools like Serena that rely on correct working directory to index and analyze codebases.

Impact

Serena provides symbolic code operations that are essential for large codebase work:

• find_symbol / find_referencing_symbols - call graph traversal
• replace_symbol_body - precise symbol-level edits
• get_symbols_overview - fast structural understanding

Without correct cwd, these tools cannot auto-detect the project, forcing users to manually activate projects every session. This defeats the purpose of semantic tooling.

Current State

Client	MCP Server cwd	Works?
Codex CLI	Project directory	✅
Codex VS Code (Remote: WSL)	/mnt/c/.../Microsoft VS Code	❌

Proposed Fix

When spawning MCP servers, pass cwd: ${workspaceFolder} (or the active workspace root). This is a one-line fix that would unblock all path-dependent MCP tools.

Workarounds Attempted

1. --project-from-cwd flag in Serena - fails because cwd is wrong
2. Manual activate_project each session - works but error-prone
3. Wrapper scripts - cannot access workspace info at spawn time
4. CODEX_WORKSPACE_ROOT env var - only available at tool-call time, not spawn time

I've also filed a feature request on Serena to use CODEX_WORKSPACE_ROOT at tool-call time (oraios/serena#970), but the proper fix should be in the VS Code extension.

Related Issues

• Spawns multiple MCP servers with wrong cwd and doesn’t clean them up #7281 - WSL2 Remote spawns MCP with wrong cwd (my previous report)
• MCP servers are not launched in the VSCode workspace folder #4222 - MCP servers not launched in workspace folder
• Add cwd (Current Working Directory) to Notify Input #5387 - Related duplicate

Environment

• Codex VS Code extension: v0.4.67
• Platform: WSL2 Ubuntu on Windows 11
• VS Code: Remote - WSL

[github-actions]

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

• [Windows] VS Code extension enabled in a Remote-SSH session to Ubuntu is having issues using MCP servers #8260
• MCPs are defined in config.toml. Codex CLI sees them but VS Code IDE extension does not see them #7820
• VSCode Codex doesn't respect sandbox_workspace_write.writable_roots in config.toml #8029

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[ginishuh]

Reviewed the potential duplicates - this is not a duplicate:

Issue	Problem	This Issue
#8260	MCP servers fail to connect in Remote-SSH	MCP works, but spawns with wrong cwd
#7820	MCPs in config.toml not visible to VS Code	MCPs are visible and functional
#8029	Sandbox settings ignored	Unrelated (sandbox vs cwd)

Key distinction: The other issues are about MCP connectivity/visibility. This issue is specifically about the working directory passed to MCP servers being the VS Code installation path instead of the workspace root.

The root cause may be shared (VS Code extension's MCP handling), but the symptom and fix are different. This requires explicitly passing cwd: ${workspaceFolder} when spawning MCP server processes.

Related but distinct from #7281 and #4222 which I also filed - those focus on the general problem, while this issue emphasizes the impact on semantic code tools like Serena.

[drozzy]

The fact that codex doesn't pass the project dir is puzzling to me.