Add hermes

modules/nixos/server/hermes.nix

@@ -0,0 +1,136 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}:
+let
+  cfg = config.mods.server.hermes;
+  auth2apiCfg = config.mods.server.auth2api;
+
+  # auth2api exposes an OpenAI-compatible endpoint; point Hermes at it.
+  auth2apiUrl = "http://${auth2apiCfg.host}:${toString auth2apiCfg.port}/v1";
+in
+with lib; {
+  options.mods.server.hermes = {
+    enable = mkEnableOption "Hermes AI agent (NousResearch)";
+
+    model = mkOption {
+      type = types.str;
+      default = "claude-sonnet-4-6";
+      description = ''
+        Model identifier as exposed by auth2api. Available aliases:
+        sonnet, haiku, opus, claude-sonnet-4-6, claude-haiku-4-5, claude-opus-4-6, etc.
+        Run: curl http://127.0.0.1:8317/v1/models
+      '';
+    };
+
+    container = {
+      enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = "Run Hermes inside a persistent Ubuntu container.";
+      };
+
+      hostUsers = mkOption {
+        type = types.listOf types.str;
+        default = [ config.mods.user.name ];
+        description = ''
+          Users that get a ~/.hermes symlink to the service stateDir and are
+          added to the hermes group for shared file access.
+        '';
+      };
+
+      extraVolumes = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        description = "Extra volume mounts (host:container:mode) for the container.";
+      };
+    };
+
+    addToSystemPackages = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Put the hermes CLI on the system PATH and set HERMES_HOME so the
+        interactive CLI shares state with the gateway service.
+      '';
+    };
+
+    extraPackages = mkOption {
+      type = types.listOf types.package;
+      default = [ ];
+      description = "Extra Nix packages available to the agent at runtime.";
+    };
+
+    stateDir = mkOption {
+      type = types.str;
+      default = "/var/lib/hermes";
+      description = "State directory (HERMES_HOME parent).";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    # Hermes needs auth2api running to have a backend to call.
+    assertions = [
+      {
+        assertion = auth2apiCfg.enable;
+        message = "mods.server.hermes requires mods.server.auth2api.enable = true";
+      }
+    ];
+
+    services.hermes-agent = {
+      enable = true;
+
+      inherit (cfg) stateDir addToSystemPackages extraPackages;
+
+      # auth2api runs unauthenticated on localhost (api-keys: []), but Hermes's
+      # provider resolver requires a non-empty key env var for any provider.
+      # AUTH2API_KEY is a dummy — auth2api ignores Bearer tokens when api-keys: [].
+      environment.AUTH2API_KEY = "auth2api";
+
+      # ── Model ──────────────────────────────────────────────────────────────
+      # Declare auth2api as a named custom provider in the providers: section.
+      # Hermes resolves it via resolve_user_provider, which accepts arbitrary
+      # base_url + key_env without needing a built-in provider slug.
+      settings = {
+        providers.auth2api = {
+          name = "auth2api (Claude via OAuth)";
+          api = auth2apiUrl;
+          key_env = "AUTH2API_KEY";
+          transport = "openai_chat";
+        };
+
+        model = {
+          default = cfg.model;
+          provider = "auth2api";
+        };
+
+        toolsets = [ "all" ];
+        max_turns = 100;
+
+        terminal = {
+          backend = "local";
+          timeout = 180;
+        };
+
+        memory = {
+          memory_enabled = true;
+          user_profile_enabled = true;
+        };
+
+        display = {
+          compact = false;
+          show_reasoning = true;
+        };
+      };
+
+      # ── Container ──────────────────────────────────────────────────────────
+      container = mkIf cfg.container.enable {
+        enable = true;
+        backend = "docker";
+        inherit (cfg.container) hostUsers extraVolumes;
+      };
+    };
+  };
+}