error:
       … while evaluating the attribute 'optionalValue.value'
         at «github:nixos/nixpkgs/241313f4e8e508cb9b13278c2b0fa25b9ca27163?narHash=sha256-vlHUuqAcbcH2RKmHbPiuQzbv1pnzzavXnI62RD0bqCU%3D»/lib/modules.nix:1312:5:
         1311|
         1312|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |     ^
         1313|   };

       … while evaluating a branch condition
         at «github:nixos/nixpkgs/241313f4e8e508cb9b13278c2b0fa25b9ca27163?narHash=sha256-vlHUuqAcbcH2RKmHbPiuQzbv1pnzzavXnI62RD0bqCU%3D»/lib/modules.nix:1312:21:
         1311|
         1312|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |                     ^
         1313|   };

       … while evaluating definitions from `/nix/store/xfg4bws749i95jvnxhymxmfwailzk38q-source/modules/transposition.nix':

       … while evaluating definitions from `/nix/store/1y8v5yh4wlb7h59xpvwj3jjiqbbz689a-source/flake.nix, via option perSystem':

       … while evaluating definitions from `/nix/store/xfg4bws749i95jvnxhymxmfwailzk38q-source/modules/transposition.nix':

       … while evaluating definitions from `/nix/store/1y8v5yh4wlb7h59xpvwj3jjiqbbz689a-source/packages/jailed-agents.nix, via option perSystem':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: Refusing to evaluate package 'claude-code-2.1.214' in /nix/store/7j1q60m17gf95k3s0gk2qvjqygnp1q36-source/pkgs/by-name/cl/claude-code/package.nix:92 because it has an unfree license (‘unfree’)
       a) To temporarily allow unfree packages, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_UNFREE=1

          Note: When using `nix shell`, `nix build`, `nix develop`, etc with a flake,
                then pass `--impure` in order to allow use of environment variables.

       b) For `nixos-rebuild` you can set
         { nixpkgs.config.allowUnfree = true; }
       in configuration.nix to override this.

       Alternatively you can configure a predicate to allow specific packages:
         { nixpkgs.config.allowUnfreePredicate = pkg: builtins.elem (lib.getName pkg) [
             "claude-code"
           ];
         }

       c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allowUnfree = true; }
       to ~/.config/nixpkgs/config.nix.