diff --git a/modules/nixos/jailed-agy.nix b/modules/nixos/jailed-agy.nix
index e8d2177..d2bb5bc 100644
--- a/modules/nixos/jailed-agy.nix
+++ b/modules/nixos/jailed-agy.nix
@@ -1,62 +1,148 @@
 {
+  config,
+  lib,
   pkgs,
   jail-nix,
+  primaryUser,
   ...
 }:
 let
   jail = jail-nix.lib.init pkgs;
+  allPackages =
+    with pkgs;
+    [
+      bashInteractive
+      curl
+      wget
+      jq
+      git
+      which
+      ripgrep
+      gnugrep
+      gnused
+      gawkInteractive
+      ps
+      findutils
+      gzip
+      unzip
+      gnutar
+      diffutils
+      coreutils
+      procps
+
+      python3
+      python3Packages.pip
+      esphome
+
+      ruby
+      go
+      gcc
+      gnumake
+      pkg-config
+
+      nix
+    ]
+    ++ config.programs.jailed-agy.extraPackages;
 in
 {
-  environment.systemPackages = [
-    # Should be started as "jailed-agy --dangerously-skip-permissions"
-    (jail "jailed-agy" pkgs.antigravity-cli (
-      with jail.combinators;
-      [
-        network
-        time-zone
-        no-new-session
-        mount-cwd
+  options.programs.jailed-agy = {
+    extraPackages = lib.mkOption {
+      type = lib.types.listOf lib.types.package;
+      default = [ ];
+      description = "Extra packages to append to the jailed-agy environment.";
+    };
+  };
 
-        (readwrite (noescape "~/.gemini"))
-        # The above is a stow-controlled symlink to the following.
-        (readwrite (noescape "~/dotfiles/legacy/.gemini"))
+  config = {
+    environment.systemPackages = [
+      (jail "jailed-agy" pkgs.antigravity-cli (
+        with jail.combinators;
+        [
+          network
+          time-zone
+          no-new-session
+          mount-cwd
 
-        # Enable easy installation of pip packages in the current directory.
-        (set-env "PYTHONPATH" (noescape "\"$PWD/.pip-packages\""))
-        (set-env "PIP_TARGET" (noescape "\"$PWD/.pip-packages\""))
-        (set-env "PIP_CACHE_DIR" (noescape "\"$PWD/.pip-cache\""))
-        (set-env "PIP_BREAK_SYSTEM_PACKAGES" "1")
+          # Enforce that the wrapper is not run as root/privileged user
+          (add-runtime ''
+            if [ "$(id -u)" -eq 0 ]; then
+              echo "Error: jailed-agy must not be run as root/privileged user!" >&2
+              exit 1
+            fi
+          '')
 
-        (add-pkg-deps (
-          with pkgs;
-          [
-            bashInteractive
-            curl
-            wget
-            jq
-            git
-            which
-            ripgrep
-            gnugrep
-            gnused
-            gawkInteractive
-            ps
-            findutils
-            gzip
-            unzip
-            gnutar
-            diffutils
-            coreutils
-            procps
+          # Automatically append --dangerously-skip-permissions to agy invocation
+          (set-argv [
+            "--dangerously-skip-permissions"
+            (noescape "\"$@\"")
+          ])
 
-            python3
-            python3Packages.pip
-            esphome
+          (readwrite (noescape "~/.gemini"))
+          # The above is a stow-controlled symlink to the following.
+          (readwrite (noescape "~/dotfiles/legacy/.gemini"))
 
-            nix
-          ]
-        ))
-      ]
-    ))
-  ];
+          # Enable easy installation of pip packages in the current directory.
+          (set-env "PYTHONPATH" (noescape "\"$PWD/.pip-packages\""))
+          (set-env "PIP_TARGET" (noescape "\"$PWD/.pip-packages\""))
+          (set-env "PIP_CACHE_DIR" (noescape "\"$PWD/.pip-cache\""))
+          (set-env "PIP_BREAK_SYSTEM_PACKAGES" "1")
+
+          # Enable easy installation and persistence of RubyGems in the current directory.
+          (set-env "GEM_HOME" (noescape "\"$PWD/.gem\""))
+
+          # Enable easy installation and persistence of Go modules and caches in the current directory.
+          (set-env "GOPATH" (noescape "\"$PWD/.go\""))
+          (set-env "GOCACHE" (noescape "\"$PWD/.go-cache\""))
+
+          # Preconfigure compiler and linker flags dynamically for all jail packages.
+          # This allows compiling Ruby gems (e.g. ffi, which requires libffi) and Go packages
+          # (e.g. YubiKey plugins, which require pcsclite) out-of-the-box.
+          (set-env "PKG_CONFIG_PATH" (
+            lib.concatStringsSep ":" (map (pkg: "${pkg.dev or pkg}/lib/pkgconfig") allPackages)
+          ))
+          (set-env "NIX_CFLAGS_COMPILE" (
+            lib.concatStringsSep " " (map (pkg: "-isystem ${pkg.dev or pkg}/include") allPackages)
+          ))
+          (set-env "NIX_LDFLAGS" (
+            lib.concatStringsSep " " (map (pkg: "-L${pkg.out or pkg}/lib") allPackages)
+          ))
+
+          # Mount system and user profiles so their packages are automatically available at runtime
+          (try-ro-bind "/run/current-system/sw" "/run/current-system/sw")
+          (try-ro-bind "/etc/profiles/per-user/${primaryUser}" "/etc/profiles/per-user/${primaryUser}")
+
+          # Mount Nix files and directories to support nix-shell and Nix operations in jail
+          (try-ro-bind "/nix/store" "/nix/store")
+          (try-ro-bind "/nix/var/nix/daemon-socket" "/nix/var/nix/daemon-socket")
+          (try-ro-bind "/nix/var/nix/profiles" "/nix/var/nix/profiles")
+          (try-ro-bind "/etc/nix" "/etc/nix")
+          (try-ro-bind "/etc/static" "/etc/static")
+
+          # Forward Nix environment variables
+          (try-fwd-env "NIX_REMOTE")
+          (try-fwd-env "NIX_PATH")
+          (try-fwd-env "NIX_SSL_CERT_FILE")
+
+          (add-pkg-deps allPackages)
+
+          # Prepend local project binary directories, system, and user bin paths to the jail's PATH.
+          # Note: We place this after `add-pkg-deps` so that local paths take highest precedence.
+          # We use explicit double quotes to allow bash to expand $PWD at runtime and handle spaces.
+          (
+            state:
+            state
+            // {
+              env = state.env // {
+                PATH =
+                  if state.env ? PATH && state.env.PATH != "" then
+                    "\"\$PWD/.gem/bin:\$PWD/.go/bin:\$PWD/.pip-packages/bin:/run/current-system/sw/bin:/etc/profiles/per-user/${primaryUser}/bin:${state.env.PATH}\""
+                  else
+                    "\"\$PWD/.gem/bin:\$PWD/.go/bin:\$PWD/.pip-packages/bin:/run/current-system/sw/bin:/etc/profiles/per-user/${primaryUser}/bin\"";
+              };
+            }
+          )
+        ]
+      ))
+    ];
+  };
 }