[BUG] Project .mcp.json not loaded when using Perforce

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?

When a user syncs our project .mcp.json file through perforce, Claude Code ignores it on startup. MCP servers that we have defined in that file are not loaded. Globally configured servers in managed settings and at the user level are loaded normally.

If we remove and then manually re-add the MCP servers to the project scope using claude mcp add --scope project, Claude Code picks up the changes immediately. (Possibly related to the files being read-only with Perforce?)

What Should Happen?

Would expect that the MCP servers distributed using .mcp.json through Perforce are detected as normal.

Error Messages/Logs

Steps to Reproduce

1. Create a valid .mcp.json in a project directory with at least one valid MCP server
2. Sync the file through Perforce (may be able to mimic this through other mechanisms?)
3. Launch Claude Code in that directory
4. Run /mcp and note that the project MCP servers are not there

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.101

Platform

AWS Bedrock

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

If we run into it again, I'll try just making the file writeable to see if that fixes it.