Add hermes

common/sandboxed-workspace/default.nix

@@ -74,6 +74,52 @@ in
               See: https://man7.org/linux/man-pages/man7/vsock.7.html
             '';
           };
+
+          extraMounts = mkOption {
+            type = types.attrsOf (types.submodule {
+              options = {
+                hostPath = mkOption {
+                  type = types.str;
+                  description = "Path on the host to bind-mount into the workspace.";
+                };
+                containerPath = mkOption {
+                  type = types.str;
+                  description = "Mount point inside the workspace.";
+                };
+                createHostPath = mkOption {
+                  type = types.bool;
+                  default = true;
+                  description = ''
+                    Whether the workspace setup service should `mkdir -p` the
+                    hostPath before the workspace starts. Set to false when the
+                    source is managed by another service (e.g. an agenix secret
+                    file at /run/agenix/<name>) so the setup doesn't race or
+                    collide with the producing service.
+                  '';
+                };
+                shift = mkOption {
+                  type = types.bool;
+                  default = true;
+                  description = ''
+                    Pass `shift=true` to the Incus disk device so host UIDs/GIDs
+                    are remapped into the container's userns. Set to false when
+                    the source filesystem can't be idmapped (e.g. tmpfs under
+                    /run on kernels without tmpfs-idmap support). With shift
+                    disabled, host-owned files show up as nobody:nogroup inside
+                    the container — make the file world-readable (mode 0444) if
+                    you need processes inside to read it.
+                  '';
+                };
+              };
+            });
+            default = { };
+            description = ''
+              Additional host→workspace bind mounts beyond the default workspace/,
+              ssh-host-keys/, and claude-config/ mounts. Useful for persisting state
+              (e.g. /var/lib/hermes) across container recreations on nixos-rebuild.
+              Only honored by the "incus" backend currently.
+            '';
+          };
         };
       });
       default = { };
@@ -82,6 +128,13 @@ in
   };
 
   config = mkIf cfg.enable {
+    assertions = lib.mapAttrsToList
+      (name: ws: {
+        assertion = ws.extraMounts == { } || ws.type == "incus";
+        message = ''sandboxed-workspace.workspaces.${name}: extraMounts is only supported for type = "incus" (got "${ws.type}").'';
+      })
+      cfg.workspaces;
+
     # Automatically enable sandbox networking when workspaces are defined
     networking.sandbox.enable = mkIf (cfg.workspaces != { }) true;
 
@@ -145,7 +198,7 @@ in
               mkdir -p /home/googlebot/sandboxed/${name}/workspace
               mkdir -p /home/googlebot/sandboxed/${name}/ssh-host-keys
               mkdir -p /home/googlebot/sandboxed/${name}/claude-config
-
+              ${lib.concatMapStrings (m: "mkdir -p ${m.hostPath}\n  ") (lib.filter (m: m.createHostPath) (lib.attrValues ws.extraMounts))}
               # Fix ownership
               chown -R googlebot:users /home/googlebot/sandboxed/${name}