Possible unsanitized path in sandbox.container.app.ts

While building mcp-customs (https://github.com/mcpcustoms/mcp-customs), an open-source scanner for MCP servers, I ran it against this repo. It flagged a file read and a file write in sandbox.container.app.ts that both take a variable named reqPath directly into fs.readFile/fs.writeFile, without an obvious sanitization step in that file.

I haven't traced the full call path to confirm whether reqPath is constrained upstream, so this may well be a non-issue — flagging it because it's a 5-minute check for someone who knows the codebase, not because I'm confident it's exploitable.

No action needed if it's already handled elsewhere — just wanted to put it in front of someone who'd know.

Start in sandbox.container.app.ts and inspect the fs.readFile and fs.writeFile calls that receive reqPath. Trace where reqPath comes from and whether it is constrained upstream; done means confirming the path is handled elsewhere or identifying the missing sanitization, with no change needed if it is already safe.

Written by the indexing model from the issue text.