Manage Sandboxes

Install Hermes Plugins

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Hermes plugins extend the Hermes runtime inside a NemoClaw-managed sandbox. They are different from NemoClaw skills and from OpenClaw plugins, so install them through the Hermes plugin path instead of skill install.

How Hermes Loads Plugins

NemoClaw sets HERMES_HOME to /sandbox/.hermes when it starts the Hermes gateway. Hermes plugin directories live under /sandbox/.hermes/plugins/<plugin-name>. NemoClaw uses the same mechanism for its built-in Hermes integration, which the sandbox image bakes into /sandbox/.hermes/plugins/nemoclaw.

The built-in NemoClaw Hermes plugin provides sandbox status tools, skill reload support, managed-tool broker patches, and runtime grounding for the OpenShell sandbox. Do not replace or remove /sandbox/.hermes/plugins/nemoclaw when you add your own plugin.

Choose an Install Path

Today, the supported path for custom Hermes plugins is to bake the plugin into a custom sandbox image and onboard from that Dockerfile. Use this path when the plugin adds Python code, runtime hooks, or dependencies that Hermes must see at gateway startup.

nemohermes <name> skill install <path> is only for SKILL.md agent skills. It uploads skill instructions and refreshes skill discovery, but it does not install Hermes runtime plugins.

Prepare a Build Directory

Put the custom Dockerfile and everything it needs to COPY in one directory. nemohermes onboard --from <Dockerfile> sends the Dockerfile’s parent directory as the Docker build context. Add a .dockerignore next to the Dockerfile to keep local caches, generated artifacts, model files, or other unneeded paths out of the staged context. NemoClaw still excludes credential-like paths such as .env*, .ssh/, .aws/, .npmrc, secrets/, *.pem, and *.key, even if .dockerignore tries to include them.

my-hermes-plugin-sandbox/
├── Dockerfile
└── my-hermes-plugin/
    ├── __init__.py
    └── requirements.txt

If you start from the stock NemoClaw Hermes Dockerfile, keep the NemoClaw Hermes image contract intact. The image must still include the generated Hermes config, NemoClaw Hermes plugin, blueprint files, and nemoclaw-start entrypoint.

A custom --from Dockerfile replaces the normal NemoClaw Hermes Dockerfile. Starting from ghcr.io/nvidia/nemoclaw/hermes-sandbox-base:latest alone is not enough unless your Dockerfile also preserves the NemoClaw Hermes layers from agents/hermes/Dockerfile.

Install the Plugin in the Image

Add your plugin after the Dockerfile has created /sandbox/.hermes. The example below shows the layer that copies a plugin directory into the Hermes plugin tree.

1COPY my-hermes-plugin/ /opt/my-hermes-plugin/
2
3USER root
4RUN mkdir -p /sandbox/.hermes/plugins/my-hermes-plugin \
5    && cp -a /opt/my-hermes-plugin/. /sandbox/.hermes/plugins/my-hermes-plugin/ \
6    && if [ -f /opt/my-hermes-plugin/requirements.txt ]; then \
7        /opt/hermes/.venv/bin/python -m pip install --no-cache-dir -r /opt/my-hermes-plugin/requirements.txt; \
8    fi \
9    && chown -R sandbox:sandbox /sandbox/.hermes/plugins/my-hermes-plugin \
10    && chmod -R a+rX /sandbox/.hermes/plugins/my-hermes-plugin
11
12USER sandbox
13WORKDIR /sandbox

Keep plugin code and dependency files inside the build directory. Avoid copying host credentials, local caches, or broad home-directory contents into the image.

Create the Sandbox

Run onboarding with the custom Dockerfile and an explicit sandbox name. NemoClaw requires a name for --from builds so a custom image cannot silently replace the default sandbox.

$nemohermes onboard --name my-hermes-build --from ./my-hermes-plugin-sandbox/Dockerfile

For non-interactive onboarding, set the same values through environment variables.

$NEMOCLAW_NON_INTERACTIVE=1 \
>NEMOCLAW_SANDBOX_NAME=my-hermes-build \
>NEMOCLAW_FROM_DOCKERFILE=./my-hermes-plugin-sandbox/Dockerfile \
>nemohermes onboard

If you resume an interrupted onboarding run, use the same Dockerfile path that started the session. NemoClaw records the custom Dockerfile path and rejects a resume that points at a different image source.

Network Access

Hermes plugins still run inside the OpenShell sandbox boundary. If a plugin calls an external API at runtime, add a policy preset for the required hostnames and binaries before you recreate the sandbox.

Hermes uses Python for plugin execution, so policy entries usually need to allow the Hermes Python runtime, such as /opt/hermes/.venv/bin/python, in addition to any command-line wrapper your plugin starts. For package downloads during sandbox runtime, use the pypi preset or a custom preset that allows the package hosts you need.

For policy concepts, refer to Network Policies. For custom preset workflows, refer to Customize Network Policy.

Common Mistakes

These are the most common places where Hermes plugin installation gets mixed up with other NemoClaw extension paths.

  • Do not use skill install for Hermes runtime plugins.
  • Do not install Hermes plugins into /sandbox/.openclaw/extensions; that path is for OpenClaw plugins.
  • Do not remove /sandbox/.hermes/plugins/nemoclaw; NemoClaw depends on that plugin for managed Hermes behavior.
  • Do not put the Dockerfile in a broad directory unless you intend to send that whole directory as the Docker build context.
  • Do not rely on .dockerignore to include credential-like paths; NemoClaw excludes those from staged custom build contexts for safety.
  • Do not assume OpenShell policy allows Python package downloads during runtime by default.

Next Steps