Nix & NixOS Setup

:::warning Tier 2 platform Nix and NixOS are Tier 2 platforms. The flake and NixOS module documented here are maintained on a best-effort basis only. Commits to main may break these packages at any point in time.

For a supported setup, use one of the standard installation paths - either Docker or an FHS environment. :::

Hermes Agent ships a Nix flake, a NixOS module, and a Home Manager module.

:::info What's different from the standard install The curl | bash installer manages Python, Node, and dependencies itself. The Nix flake replaces all of that — every Python dependency is a Nix derivation built by uv2nix, and runtime tools (Node.js, git, ripgrep, ffmpeg) are wrapped into the binary's PATH. There is no runtime pip, no venv activation, no npm install.

For non-NixOS users, this only changes the install step. Everything after (hermes setup, hermes gateway install, config editing) works identically to the standard install.

For NixOS module users, the entire lifecycle is different: configuration lives in configuration.nix, secrets go through sops-nix/agenix, the service is a systemd unit, and CLI config commands are blocked. You manage hermes the same way you manage any other NixOS service. :::

Prerequisites

• Nix with flakes enabled — Determinate Nix recommended (enables flakes by default)
• API keys for the services you want to use (at minimum: an OpenRouter or Anthropic key)

Quick Start (Any Nix User)

No clone needed. Nix fetches, builds, and runs everything:

# Run the desktop app
nix run github:NousResearch/hermes-agent#desktop

# Or install persistently
nix profile install github:NousResearch/hermes-agent#desktop

# run the tui
nix run github:NousResearch/hermes-agent -- setup
nix run github:NousResearch/hermes-agent -- --tui

# or install it in your profile
nix profile install github:NousResearch/hermes-agent
hermes setup
hermes --tui

After nix profile install, hermes, hermes-agent, and hermes-acp are on your PATH. From here, the workflow is identical to the standard installation — hermes setup walks you through provider selection, hermes gateway install sets up a launchd (macOS) or systemd user service, and config lives in ~/.hermes/.

:::warning Messaging platforms (Discord, Telegram, Slack) The default package includes ALL libraries hermes-agent might need. if you want a smaller variant, check the other flake outputs.

The default package adds ~700 MB to the closure. If you only need messaging platforms, #messaging adds just ~33 MB.

:::

git clone https://github.com/NousResearch/hermes-agent.git
cd hermes-agent
nix develop
hermes setup

NixOS Module

The flake exports nixosModules.default — a full NixOS service module that declaratively manages user creation, directories, config generation, secrets, documents, and service lifecycle.

:::note This module needs NixOS. Hermes is an agent for one person. If you want an agent for one person and not a system service, use the Home Manager module. That module runs on NixOS and on each other system that Home Manager supports. :::

Add the Flake Input

# /etc/nixos/flake.nix (or your system flake)
{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    hermes-agent.url = "github:NousResearch/hermes-agent";
  };

  outputs = { nixpkgs, hermes-agent, ... }: {
    nixosConfigurations.your-host = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        hermes-agent.nixosModules.default
        ./configuration.nix
      ];
    };
  };
}

Minimal Configuration

# configuration.nix
{ config, ... }: {
  services.hermes-agent = {
    enable = true;
    settings.model.default = "anthropic/claude-sonnet-4";
    environmentFiles = [ config.sops.secrets."hermes-env".path ];
    addToSystemPackages = true;
  };
}

That's it. nixos-rebuild switch creates the hermes user, generates config.yaml, wires up secrets, and starts the gateway — a long-running service that connects the agent to messaging platforms (Telegram, Discord, etc.) and listens for incoming messages.

:::warning Secrets are required The environmentFiles line above assumes you have sops-nix or agenix configured. The file should contain at least one LLM provider key (e.g., OPENROUTER_API_KEY=sk-or-...). See Secrets Management for full setup. If you don't have a secrets manager yet, you can use a plain file as a starting point — just ensure it's not world-readable:

echo "OPENROUTER_API_KEY=sk-or-your-key" | sudo install -m 0600 -o hermes /dev/stdin /var/lib/hermes/env

services.hermes-agent.environmentFiles = [ "/var/lib/hermes/env" ];

:::

:::tip addToSystemPackages Setting addToSystemPackages = true does two things: puts the hermes CLI on your system PATH and sets HERMES_HOME system-wide so the interactive CLI shares state (sessions, skills, cron) with the gateway service. Without it, running hermes in your shell creates a separate ~/.hermes/ directory. :::

Container-aware CLI

:::info When container.enable = true and addToSystemPackages = true, every hermes command on the host automatically routes into the managed container. This means your interactive CLI session runs inside the same environment as the gateway service — with access to all container-installed packages and tools.

• The routing is transparent: hermes chat, hermes sessions list, hermes --version, etc. all exec into the container under the hood
• All CLI flags are forwarded as-is
• If the container isn't running, the CLI retries briefly (5s with a spinner for interactive use, 10s silently for scripts) then fails with a clear error — no silent fallback
• For developers working on the hermes codebase, set HERMES_DEV=1 to bypass container routing and run the local checkout directly

Set container.hostUsers to create a ~/.hermes symlink to the service state directory, so the host CLI and the container share sessions, config, and memories:

services.hermes-agent = {
  container.enable = true;
  container.hostUsers = [ "your-username" ];
  addToSystemPackages = true;
};

Users listed in hostUsers are automatically added to the hermes group for file permission access.

Podman users: The NixOS service runs the container as root. Docker users get access via the docker group socket, but Podman's rootful containers require sudo. Grant passwordless sudo for your container runtime:

security.sudo.extraRules = [{
  users = [ "your-username" ];
  commands = [{
    command = "/run/current-system/sw/bin/podman";
    options = [ "NOPASSWD" ];
  }];
}];

The CLI auto-detects when sudo is needed and uses it transparently. Without this, you'll need to run sudo hermes chat manually. :::

Verify It Works

After nixos-rebuild switch, check that the service is running:

# Check service status
systemctl status hermes-agent

# Watch logs (Ctrl+C to stop)
journalctl -u hermes-agent -f

# If addToSystemPackages is true, test the CLI
hermes --version
hermes config       # shows the generated config

Choosing a Deployment Mode

The module supports two modes, controlled by container.enable:

To enable container mode, add one line:

{
  services.hermes-agent = {
    enable = true;
    container.enable = true;
    # ... rest of config is identical
  };
}

:::info Container mode auto-enables virtualisation.docker.enable via mkDefault. If you use Podman instead, set container.backend = "podman" and virtualisation.docker.enable = false. :::

Configuration

Declarative Settings

The settings option accepts an arbitrary attrset that is rendered as config.yaml. It supports deep merging across multiple module definitions (via lib.recursiveUpdate), so you can split config across files:

# base.nix
services.hermes-agent.settings = {
  model.default = "anthropic/claude-sonnet-4";
  toolsets = [ "all" ];
  terminal = { backend = "local"; timeout = 180; };
};

# personality.nix
services.hermes-agent.settings = {
  display = { compact = false; personality = "kawaii"; };
  memory = { memory_enabled = true; user_profile_enabled = true; };
};

Both are deep-merged at evaluation time. Nix-declared keys always win over keys in an existing config.yaml on disk, but user-added keys that Nix doesn't touch are preserved. This means if the agent or a manual edit adds keys like skills.disabled or streaming.enabled, they survive nixos-rebuild switch.

:::note Model naming settings.model.default uses the model identifier your provider expects. With OpenRouter (the default), these look like "anthropic/claude-sonnet-4" or "google/gemini-3-flash". If you're using a provider directly (Anthropic, OpenAI), set settings.model.base_url to point at their API and use their native model IDs (e.g., "claude-sonnet-4-20250514"). When no base_url is set, Hermes defaults to OpenRouter. :::

:::tip Discovering available config keys Run nix build .#configKeys && cat result to see every leaf config key extracted from Python's DEFAULT_CONFIG. You can paste your existing config.yaml into the settings attrset — the structure maps 1:1. :::

{ config, ... }: {
  services.hermes-agent = {
    enable = true;
    container.enable = true;

    # ── Model ──────────────────────────────────────────────────────────
    settings = {
      model = {
        base_url = "https://openrouter.ai/api/v1";
        default = "anthropic/claude-opus-4.6";
      };
      toolsets = [ "all" ];
      max_turns = 100;
      terminal = { backend = "local"; cwd = "."; timeout = 180; };
      compression = {
        enabled = true;
        threshold = 0.85;
        summary_model = "google/gemini-3-flash-preview";
      };
      memory = { memory_enabled = true; user_profile_enabled = true; };
      display = { compact = false; personality = "kawaii"; };
      agent = { max_turns = 60; verbose = false; };
    };

    # ── Secrets ─────────────────────────────────────���──────────────────
    environmentFiles = [ config.sops.secrets."hermes-env".path ];

    # ── Documents ──────────────────────────────────────────────────────
    # USER.md is memory, so it goes to HERMES_HOME. Workspace files use
    # `documents`, and that option needs an explicit `workingDirectory`.
    hermesHomeFiles = {
      "memories/USER.md" = ./documents/USER.md;
    };

    # ── MCP Servers ────────────────────────────────────────────────────
    mcpServers.filesystem = {
      command = "npx";
      args = [ "-y" "@modelcontextprotocol/server-filesystem" "/data/workspace" ];
    };

    # ── Container options ──────────────────────────────────────────────
    container = {
      image = "ubuntu:24.04";
      backend = "docker";
      hostUsers = [ "your-username" ];
      extraVolumes = [ "/home/user/projects:/projects:rw" ];
      extraOptions = [ "--gpus" "all" ];
    };

    # ── Service tuning ─────────────────────────────────────────────────
    addToSystemPackages = true;
    extraArgs = [ "--verbose" ];
    restart = "always";
    restartSec = 5;
  };
}

Escape Hatch: Bring Your Own Config

If you'd rather manage config.yaml entirely outside Nix, use configFile:

services.hermes-agent.configFile = /etc/hermes/config.yaml;

This bypasses settings entirely — no merge, no generation. The file is copied as-is to $HERMES_HOME/config.yaml on each activation.

Customization Cheatsheet

Quick reference for the most common things Nix users want to customize:

Secrets Management

:::danger Never put API keys in settings or environment Values in Nix expressions end up in /nix/store, which is world-readable. Always use environmentFiles with a secrets manager. :::

Both environment (non-secret vars) and environmentFiles (secret files) are merged into $HERMES_HOME/.env at activation time (nixos-rebuild switch). Hermes reads this file on every startup, so changes take effect with a systemctl restart hermes-agent — no container recreation needed.

sops-nix

{
  sops = {
    defaultSopsFile = ./secrets/hermes.yaml;
    age.keyFile = "/home/user/.config/sops/age/keys.txt";
    secrets."hermes-env" = { format = "yaml"; };
  };

  services.hermes-agent.environmentFiles = [
    config.sops.secrets."hermes-env".path
  ];
}

The secrets file contains key-value pairs:

# secrets/hermes.yaml (encrypted with sops)
hermes-env: |
    OPENROUTER_API_KEY=sk-or-...
    TELEGRAM_BOT_TOKEN=123456:ABC...
    ANTHROPIC_API_KEY=sk-ant-...

agenix

{
  age.secrets.hermes-env.file = ./secrets/hermes-env.age;

  services.hermes-agent.environmentFiles = [
    config.age.secrets.hermes-env.path
  ];
}

OAuth / Auth Seeding

For platforms requiring OAuth (e.g., Discord), use authFile to seed credentials on first deploy:

{
  services.hermes-agent = {
    authFile = config.sops.secrets."hermes/auth.json".path;
    # authFileForceOverwrite = true;  # overwrite on every activation
  };
}

The file is only copied if auth.json doesn't already exist (unless authFileForceOverwrite = true). Runtime OAuth token refreshes are written to the state directory and preserved across rebuilds.

Documents

Hermes reads files from two directories. Thus there are two options. Use the option for the directory that the file must go into.

documents installs into the working directory of the agent, which is workingDirectory. The agent reads its project context from that workspace:

{
  services.hermes-agent = {
    # documents needs this option. Read the note below.
    workingDirectory = "/var/lib/hermes/workspace";
    documents = {
      "AGENTS.md" = ./documents/AGENTS.md;   # path reference, copied from Nix store
      "notes/oncall.md" = "Page #infra before restarting anything.";
    };
  };
}

:::warning documents needs an explicit workingDirectory The module refuses documents until you set workingDirectory. The default of that option is different on each module. It is your home directory on Home Manager, and ${stateDir}/workspace on NixOS. Thus an unset default puts the files in a directory that you did not select. A directory with the same path as the default is a correct selection, and it satisfies the rule. :::

hermesHomeFiles installs into HERMES_HOME. Hermes reads the identity file and the memory files of the agent from that directory. SOUL.md and memories/ work only from there. A SOUL.md in documents makes a workspace file. Hermes does not load that file as the identity:

{
  services.hermes-agent.hermesHomeFiles = {
    "SOUL.md" = "You are a helpful AI assistant.";
    "memories/USER.md" = ./documents/USER.md;
  };
}

Each value is a string or a path. A key in either option can contain subdirectories, and the module makes the parent directories. Each activation installs the files again.

hermesHomeFiles needs no workingDirectory, because the module owns the HERMES_HOME directory. Most users want hermesHomeFiles.

MCP Servers

The mcpServers option declaratively configures MCP (Model Context Protocol) servers. Each server uses either stdio (local command) or HTTP (remote URL) transport.

Stdio Transport (Local Servers)

{
  services.hermes-agent.mcpServers = {
    filesystem = {
      command = "npx";
      args = [ "-y" "@modelcontextprotocol/server-filesystem" "/data/workspace" ];
    };
    github = {
      command = "npx";
      args = [ "-y" "@modelcontextprotocol/server-github" ];
      env.GITHUB_PERSONAL_ACCESS_TOKEN = "\${GITHUB_TOKEN}"; # resolved from .env
    };
  };
}

:::tip Environment variables in env values are resolved from $HERMES_HOME/.env at runtime. Use environmentFiles to inject secrets — never put tokens directly in Nix config. :::

HTTP Transport (Remote Servers)

{
  services.hermes-agent.mcpServers.remote-api = {
    url = "https://mcp.example.com/v1/mcp";
    headers.Authorization = "Bearer \${MCP_REMOTE_API_KEY}";
    timeout = 180;
  };
}

HTTP Transport with OAuth

Set auth = "oauth" for servers using OAuth 2.1. Hermes implements the full PKCE flow — metadata discovery, dynamic client registration, token exchange, and automatic refresh.

{
  services.hermes-agent.mcpServers.my-oauth-server = {
    url = "https://mcp.example.com/mcp";
    auth = "oauth";
  };
}

Tokens are stored in $HERMES_HOME/mcp-tokens/<server-name>.json and persist across restarts and rebuilds.

The first OAuth authorization requires a browser-based consent flow. In a headless deployment, Hermes prints the authorization URL to stdout/logs instead of opening a browser.

Option A: Interactive bootstrap — run the flow once via docker exec (container) or sudo -u hermes (native):

# Container mode
docker exec -it hermes-agent \
  hermes mcp add my-oauth-server --url https://mcp.example.com/mcp --auth oauth

# Native mode
sudo -u hermes HERMES_HOME=/var/lib/hermes/.hermes \
  hermes mcp add my-oauth-server --url https://mcp.example.com/mcp --auth oauth

The container uses --network=host, so the OAuth callback listener on 127.0.0.1 is reachable from the host browser.

Option B: Pre-seed tokens — complete the flow on a workstation, then copy tokens:

hermes mcp add my-oauth-server --url https://mcp.example.com/mcp --auth oauth
scp ~/.hermes/mcp-tokens/my-oauth-server{,.client}.json \
    server:/var/lib/hermes/.hermes/mcp-tokens/
# Ensure: chown hermes:hermes, chmod 0600

Sampling (Server-Initiated LLM Requests)

Some MCP servers can request LLM completions from the agent:

{
  services.hermes-agent.mcpServers.analysis = {
    command = "npx";
    args = [ "-y" "analysis-server" ];
    sampling = {
      enabled = true;
      model = "google/gemini-3-flash";
      max_tokens_cap = 4096;
      timeout = 30;
      max_rpm = 10;
    };
  };
}

Managed Mode

When hermes runs via the NixOS module, the following CLI commands are blocked with a descriptive error pointing you to configuration.nix:

This prevents drift between what Nix declares and what's on disk. Detection uses two signals:

1. The HERMES_MANAGED environment variable. The service sets it, and the gateway process reads it.
2. The .managed marker file in HERMES_HOME. The activation script writes it, and an interactive shell reads it. Thus the CLI also blocks a command such as docker exec -it hermes-agent hermes config set ....

Both signals hold the name of the system that manages the install. Thus the refusal names the correct rebuild command. The NixOS module gives sudo nixos-rebuild switch. The Home Manager module gives home-manager switch.

Home Manager Module

The flake also exports homeManagerModules.default. Hermes is an agent for one person. The credentials, the memory, the sessions and the cron jobs all belong to that person. Thus a user service is the correct shape on a personal machine. It runs on each distribution that Home Manager supports, and not only on NixOS.

The option set is the same set that the NixOS module uses. It is services.hermes-agent, with the same settings, environmentFiles, documents, mcpServers, extraPlugins and backend options. Each example above works here without a change. Only the necessary parts are different:

Add the Flake Input

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    home-manager.url = "github:nix-community/home-manager";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";
    hermes-agent.url = "github:NousResearch/hermes-agent";
  };
}

Then import the module into your Home Manager configuration. The configuration can be standalone. It can also be under home-manager.users.<name> in a NixOS or nix-darwin configuration:

{
  imports = [ hermes-agent.homeManagerModules.default ];

  services.hermes-agent = {
    enable = true;
    gateway.enable = true;
    settings.model.default = "anthropic/claude-sonnet-4";
    environmentFiles = [ config.sops.secrets."hermes-env".path ];
  };
}

home-manager switch makes ~/.hermes, writes config.yaml, builds .env and starts the gateway as a user service.

:::warning Enable linger, or the service stops at logout CAUTION: Enable linger for your account. Without linger, systemd stops the user manager when your last session ends, and the gateway stops with it. Home Manager cannot set linger, because linger is a property of the account:

# NixOS
users.users.your-username.linger = true;

# anywhere else
sudo loginctl enable-linger your-username

macOS has no equivalent option. A launchd agent with RunAtLoad starts at login and continues to run. :::

Running the Desktop / Dashboard Backend

gateway.enable runs the messaging gateway for Telegram, Discord, Slack and the other platforms. Hermes Desktop and the web dashboard connect to a different process, which is hermes serve or hermes dashboard. backend.mode runs that process with the gateway:

{
  services.hermes-agent = {
    enable = true;
    gateway.enable = true;      # messaging platforms
    backend.mode = "dashboard"; # + the browser dashboard on 127.0.0.1:9119
    backend.port = 9119;
  };
}

serve runs without a user interface. It gives the /api/ws and /api/pty sockets that Hermes Desktop connects to, and it does not build the web application. dashboard gives all of that, and also serves the browser admin panel. Both processes use one HERMES_HOME with the gateway. Thus the sessions, the skills, the memory and the cron jobs are the same for all of them. backend.mode works in the same way on the NixOS module, but not in container mode.

:::warning Binding to an address other than loopback The default address is 127.0.0.1. Each other address starts the authentication gate of the dashboard. The server also refuses each request with a Host header that is different from the address that the server bound to. This is a defence against DNS rebinding. Bind to the name or the address that your client uses. :::

Verify It Works

# Linux
systemctl --user status hermes-agent
journalctl --user -u hermes-agent -f

# macOS
launchctl list | grep hermes
tail -f ~/Library/Logs/hermes-agent.log

hermes --version
hermes config     # shows the configuration that Nix wrote

Container Architecture

:::info This section is only relevant if you're using container.enable = true. Skip it for native mode deployments. :::

When container mode is enabled, hermes runs inside a persistent Ubuntu container with the Nix-built binary bind-mounted read-only from the host:

Host                                    Container
────                                    ─────────
/nix/store/...-hermes-agent-0.1.0  ──►  /nix/store/... (ro)
~/.hermes -> /var/lib/hermes/.hermes       (symlink bridge, per hostUsers)
/var/lib/hermes/                    ──►  /data/          (rw)
  ├── current-package -> /nix/store/...    (symlink, updated each rebuild)
  ├── .gc-root -> /nix/store/...           (prevents nix-collect-garbage)
  ├── .container-identity                  (sha256 hash, triggers recreation)
  ├── .hermes/                             (HERMES_HOME)
  │   ├── .env                             (merged from environment + environmentFiles)
  │   ├── config.yaml                      (Nix-generated, deep-merged by activation)
  │   ├── .managed                         (marker file)
  │   ├── .container-mode                  (routing metadata: backend, exec_user, etc.)
  │   ├── state.db, sessions/, memories/   (runtime state)
  │   └── mcp-tokens/                      (OAuth tokens for MCP servers)
  ├── home/                                ──►  /home/hermes    (rw)
  └── workspace/                           (agent working directory)
      ├── AGENTS.md                        (from the documents option)
      └── (agent-created files)

Container writable layer (apt/pip/npm):   /usr, /usr/local, /tmp

The Nix-built binary works inside the Ubuntu container because /nix/store is bind-mounted — it brings its own interpreter and all dependencies, so there's no reliance on the container's system libraries. The container entrypoint resolves through a current-package symlink: /data/current-package/bin/hermes gateway run --replace. On nixos-rebuild switch, only the symlink is updated — the container keeps running.

What Persists Across What

The container is only recreated when its identity hash changes. The hash covers: schema version, image, extraVolumes, extraOptions, and the entrypoint script. Changes to environment variables, settings, documents, or the hermes package itself do not trigger recreation.

:::warning Writable layer loss When the identity hash changes (image upgrade, new volumes, new container options), the container is destroyed and recreated from a fresh pull of container.image. Any apt install, pip install, or npm install packages in the writable layer are lost. State in /data and /home/hermes is preserved (these are bind mounts).

If the agent relies on specific packages, consider baking them into a custom image (container.image = "my-registry/hermes-base:latest") or scripting their installation in the agent's SOUL.md. :::

GC Root Protection

The preStart script creates a GC root at ${stateDir}/.gc-root pointing to the current hermes package. This prevents nix-collect-garbage from removing the running binary. If the GC root somehow breaks, restarting the service recreates it.

Plugins

The NixOS module supports declarative plugin installation — no imperative hermes plugins install needed.

Directory Plugins (extraPlugins)

For plugins that are just a source tree with plugin.yaml + __init__.py (e.g., hermes-lcm):

services.hermes-agent.extraPlugins = [
  (pkgs.fetchFromGitHub {
    owner = "stephenschoettler";
    repo = "hermes-lcm";
    rev = "v0.7.0";
    hash = "sha256-...";
  })
];

Plugins are symlinked into $HERMES_HOME/plugins/ at activation time. Hermes discovers them via its normal directory scan. Removing a plugin from the list and running nixos-rebuild switch removes the symlink.

Entry-Point Plugins (extraPythonPackages)

For pip-packaged plugins that register via [project.entry-points."hermes_agent.plugins"] (e.g., rtk-hermes):

services.hermes-agent.extraPythonPackages = [
  (pkgs.python312Packages.buildPythonPackage {
    pname = "rtk-hermes";
    version = "1.0.0";
    src = pkgs.fetchFromGitHub {
      owner = "ogallotti";
      repo = "rtk-hermes";
      rev = "v1.0.0";
      hash = "sha256-...";
    };
    format = "pyproject";
    build-system = [ pkgs.python312Packages.setuptools ];
  })
];

The package's site-packages is added to PYTHONPATH in the hermes wrapper. importlib.metadata discovers the entry point at session start.

Optional Dependency Groups (extraDependencyGroups)

For optional extras declared in hermes-agent's pyproject.toml, use extraDependencyGroups to include them in the sealed venv at build time. This is required for any extra not in the default [all] set — on Nix, runtime installation into the read-only store is not possible.

# Enable Discord, Telegram, Slack
services.hermes-agent.extraDependencyGroups = [ "messaging" ];

# Enable a memory provider
services.hermes-agent = {
  extraDependencyGroups = [ "hindsight" ];
  settings.memory.provider = "hindsight";
};

This is resolved by uv alongside core dependencies — no PYTHONPATH patching, no collision risk. Available groups:

Or use the pre-built #messaging or #full flake packages instead of per-extra configuration (see Quick Start).

When to use which:

Combining Both

A directory plugin with third-party Python dependencies needs both options:

services.hermes-agent = {
  extraPlugins = [ my-plugin-src ];          # plugin source
  extraPythonPackages = [ pkgs.python312Packages.redis ];  # its Python dep
  extraPackages = [ pkgs.redis ];            # system binary it needs
};

Using the Overlay

External flakes can override the package directly:

{
  inputs.hermes-agent.url = "github:NousResearch/hermes-agent";
  outputs = { hermes-agent, nixpkgs, ... }: {
    nixpkgs.overlays = [ hermes-agent.overlays.default ];
    # Then:
    #   pkgs.hermes-agent.override { extraPythonPackages = [...]; }
    #   pkgs.hermes-agent.override { extraDependencyGroups = [ "hindsight" ]; }
  };
}

Plugin Configuration

Plugins still need to be enabled in config.yaml. Add them via the declarative settings:

services.hermes-agent.settings.plugins.enabled = [
  "hermes-lcm"
  "rtk-rewrite"
];

:::note A build-time collision check prevents plugin packages from shadowing core hermes dependencies. If a plugin provides a package already in the sealed venv, nixos-rebuild fails with a clear error. :::

Development

Dev Shell

The flake provides a development shell with Python 3.12, uv, Node.js, and all runtime tools:

cd hermes-agent
nix develop

# Shell provides:
#   - Python 3.12 + uv (deps installed into .venv on first entry)
#   - Node.js 26, ripgrep, git, openssh, ffmpeg on PATH
#   - Stamp-file optimization: re-entry is near-instant if deps haven't changed

hermes setup
hermes chat

direnv (Recommended)

The included .envrc activates the dev shell automatically:

cd hermes-agent
direnv allow    # one-time
# Subsequent entries are near-instant (stamp file skips dep install)

Flake Checks

The flake includes build-time verification that runs in CI and locally:

# Run all checks
nix flake check

# Individual checks
nix build .#checks.x86_64-linux.package-contents   # binaries exist + version
nix build .#checks.x86_64-linux.entry-points-sync  # pyproject.toml ↔ Nix package sync
nix build .#checks.x86_64-linux.cli-commands        # gateway/config subcommands
nix build .#checks.x86_64-linux.managed-guard       # HERMES_MANAGED blocks mutation
nix build .#checks.x86_64-linux.bundled-skills      # skills present in package
nix build .#checks.x86_64-linux.config-roundtrip    # merge script preserves user keys

Options Reference

Core

Configuration

Secrets & Environment

Documents

MCP Servers

Service Behavior

Backend (hermes serve / hermes dashboard)

This option runs the process that Hermes Desktop and the web dashboard connect to, with the gateway. You cannot use it with container.enable.

Home Manager only

Container (NixOS only)

Directory Layout

Native Mode

/var/lib/hermes/                     # stateDir (owned by hermes:hermes, 0750)
├── .hermes/                         # HERMES_HOME
│   ├── SOUL.md                      # from hermesHomeFiles: the agent identity
│   ├── config.yaml                  # Nix-generated (deep-merged each rebuild)
│   ├── .managed                     # Marker: CLI config mutation blocked
│   ├── .env                         # Merged from environment + environmentFiles
│   ├── auth.json                    # OAuth credentials (seeded, then self-managed)
│   ├── gateway.pid
│   ├── state.db
│   ├── mcp-tokens/                  # OAuth tokens for MCP servers
│   ├── sessions/
│   ├── memories/
│   ├── skills/
│   ├── cron/
│   └── logs/
├── home/                            # Agent HOME
└── workspace/                       # Agent working directory
    ├── AGENTS.md                    # from the documents option
    └── (agent-created files)

Home Manager

~/.hermes/                           # hermesHome (HERMES_HOME), 0700
├── SOUL.md                          # from hermesHomeFiles
├── config.yaml                      # written by Nix, merged at each activation
├── .managed                         # marker: names the system that manages this
├── .env                             # written again from environment + environmentFiles
├── auth.json                        # OAuth credentials: seeded, then Hermes owns it
├── memories/  sessions/  skills/  cron/  logs/  plugins/
└── (runtime state)

~/                                   # workingDirectory, your home by default
└── AGENTS.md                        # from the documents option

Container Mode

Same layout, mounted into the container:

Updating

# Update the flake input (run from the directory containing flake.nix)
cd /etc/nixos && nix flake update hermes-agent

# Rebuild
sudo nixos-rebuild switch          # for the NixOS module
home-manager switch                # for the Home Manager module

In container mode, the current-package symlink is updated and the agent picks up the new binary on restart. No container recreation, no loss of installed packages.

Troubleshooting

:::tip Podman users All docker commands below work the same with podman. Substitute accordingly if you set container.backend = "podman". :::

Service Logs

# Both modes use the same systemd unit
journalctl -u hermes-agent -f

# Container mode: also available directly
docker logs -f hermes-agent

Container Inspection

systemctl status hermes-agent
docker ps -a --filter name=hermes-agent
docker inspect hermes-agent --format='{{.State.Status}}'
docker exec -it hermes-agent bash
docker exec hermes-agent readlink /data/current-package
docker exec hermes-agent cat /data/.container-identity

Force Container Recreation

If you need to reset the writable layer (fresh Ubuntu):

sudo systemctl stop hermes-agent
docker rm -f hermes-agent
sudo rm /var/lib/hermes/.container-identity
sudo systemctl start hermes-agent

Verify Secrets Are Loaded

If the agent starts but can't authenticate with the LLM provider, check that the .env file was merged correctly:

# Native mode
sudo -u hermes cat /var/lib/hermes/.hermes/.env

# Container mode
docker exec hermes-agent cat /data/.hermes/.env

GC Root Verification

nix-store --query --roots $(docker exec hermes-agent readlink /data/current-package)

Common Issues