[gverrilla]

In Claude Code I think I can solve this with simply a rule + PreToolUse hook. The hook denies Reading the .env, and the rule sets a protocol of what not do to, and what to do instead :`$(grep KEY_NAME ~/.claude/secrets.env | cut -d= -f2-)`.

When would something like that not work?

[apwheele]

Claude code inherits from the environment shell. So it could create a python program (or whatever language) to read the file:

    # get_info.py
    with open('~/.claude/secrets.env', 'r') as file:
        content = file.read()
        print(content)

And then run `python get_info.py`.

While this inheritance is convenient for testing code, it is difficult to isolate Claude in a way that you can run/test your application without giving up access to secrets.

If you can, IP whitelisting your secrets so if they are leaked is not a problem is an approach I recommend.

[ctmnt]

You can just set `"deny": ["Read(./.env)", "Read(./.env.*)"]` if you want to keep it simple and rely on Claude's own mechanisms.

[gverrilla]

last time I tried allowing/denying tool usage I found a lot of bugs, so I stay away from that as much as I can. Opus is quite smart, rules/ work quite well for things like this in my experience. The way I see it, sandboxing is only really important for people doing specific stuff like pentests, games, adversarial stuff, etc.