opencode-jail-devenv

Status: Alpha - Experimental, may have breaking changes

A devenv module that provides secure sandboxing for the opencode LLM agent using jail.nix. Run AI coding agents safely with restricted filesystem and network access, preventing accidental or malicious system modifications.

Inspired by How I Run LLM Agents in a Secure Nix Sandbox.

Dependencies

• devenv
• jail.nix
• opencode

Installation

Add to your devenv.yaml:

inputs:
  opencode:
    url: github:refnil/opencode-jail-devenv
  jail-nix:
    url: sourcehut:~alexdavid/jail.nix

imports:
  - opencode

Options

Option	Type	Default	Description
programs.opencode.enable	bool	false	Enable the opencode module
programs.opencode.addProjectPackages	bool	true	Include config.packages in the opencode environment
programs.opencode.basePackages	list	See below	Base packages available to the agent (curl, git, ripgrep, etc.)
programs.opencode.packages	list	[]	Additional custom packages to add
programs.opencode.opencodePackage	package	pkgs.opencode	The opencode package to use
programs.opencode.baseJailCombinators	list	See below	Base sandbox permissions
programs.opencode.jailCombinators	list	[]	Additional sandbox permissions

Default base packages: bashInteractive, curl, wget, jq, git, which, ripgrep, gnugrep, gawkInteractive, ps, findutils, gzip, unzip, gnutar, diffutils

Default jail permissions: network access, timezone info, no new sessions, tmpfs at /tmp, read-write access to ~/.config/opencode, ~/.local/share/opencode, ~/.local/state/opencode, and read-write access to the project root.

Example Configuration

# devenv.nix
{ pkgs, ... }: {
  # Standard Rust environment - this compiler is automatically included
  # in the opencode jail through addProjectPackages = true
  languages.rust.enable = true;
  languages.rust.channel = "stable";

  programs.opencode = {
    enable = true;

    # Packages only available inside the jail - analysis and management tools
    packages = with pkgs; [
      cargo-expand     # Expand macros to see generated code
      cargo-edit       # Add/remove dependencies via CLI
      cargo-tree       # Visualize dependency tree
    ];

    # Share cargo registry cache between host and jail for faster builds
    jailCombinators = with pkgs.jail.combinators; [
      (rw-bind "~/.cargo/registry" "~/.cargo/registry")
    ];
  };
}