If you don't do that, the agent will be able to incidentally upload them. What if the model runs "rg foo", and one of those files contains the string "foo"? It uploads the tool output, which includes the file contents.

And so, the only solution is to make it so the codex process is unable to access those files, hence using a container, or unix permissions, or deleting the files. Which you can already do.

I imagine this isn't resolved primarily because people expect it to apply to bash tool use, not just the "read" and "edit" tools, and people also expect those files to still be accessible i.e. if the agent invokes "make", which makes it impossible to solve perfectly.

People just need to learn how to use the tools their system already provides them. i.e., chmod

As others here have pointed out, it's exceedingly unlikely that a blocklist like proposed in the issue would ever be complete. You shouldn't allow agents direct yolo-access to your machine if it has sensitive data.

Codex works particularly well as a remote agent harness because of its client-server architecture: The server component runs in the container, which might be remote, while the client runs locally. So, in contrast to e.g. the claude cli where the frontend also runs remotely, there's no lag when you write/edit prompts.

In any case. There are solutions in the comments on the issue, as well as this hn thread.

I've been looking into a "workspace" concept that involves an entire cloud VM being spun up as part of an agent conversation such that code changes can be iterated without touching the user's local machine or other trusted contexts. All the agent's tools only have effect when supplied with a specific workspace guid. CLI tools like git are not authorized to talk to the remotes in this arrangement. The machine is initialized with a clone and no way to talk to origin. There are dedicated methods in the harness that can reach into the VM and pull out a change set for deterministic PR generation in the secure contexts (e.g. when the agent calls "ReadyForReview" or similar).

It's a good idea as a hint to agents about what files it should ignore (because they'd be of no value and only chew up tokens).

However, using it to prevent exposure of secrets would be a BIG mistake. There's simply no way to guarantee that an agent will ignore things in the ignore file. And even a harness-enforced restriction would still be in-process, which a rogue agent could trivially compromise. For security, use a sandbox. Nothing else will do.

I do AI sandboxes (FOSS, free forever, no rug pull): https://github.com/kstenerud/yoloai

Regardless of what technique you use, you need a deputy, you wouldn't ask an employee not to go into the vault, right? You would lock the vault. Well you can ask the employee not to go into the vault, and you can also ask codex not to use certain files, but if you need more certainty, you need to it outside.

The issue seems to be that people want to ask their agent to do everything, they want the agent to lock themselves out of some system, they want the agent to install itself, they want the agent to write their prompts so they don't have to write them. At some point there's some things YOU have to do, and you have to DO them.

I contributed to a tool for this problem that is lower-friction than traditional sandboxing:

greywall.io

But you should use something to contain an agent runtime. The idea that people run things like codex on their machines with regular user permissions is baffling to me.

Qubes is not practical for mobile laptop use and non expert users.

BUT it would be very practical for other OSes to offer the option of VM-style isolated containers as first class objects that are easy to make and configure boundaries on, and for which first class interop facilities are provided (eg “send this file to this container” “send the clipboard to this container’s clipboard).