hetzner-mcp

An MCP server for Hetzner. Cloud projects, account resources and dedicated servers from one connection, with the whole REST API reachable — not just the parts somebody wrapped in a tool.

npx @donedynamics/hetzner-mcp install

What it is

Hetzner's APIs have 221 operations. Publishing 221 tools would spend the host's context budget on schemas it never calls, so this server publishes thirteen: the loop an operator actually repeats, plus a searchable catalog that reaches everything else.

It is built for people running more than one thing. A Hetzner Cloud token is created inside a project and cannot see any other project — there is no project parameter anywhere in the API — so ten projects across three accounts are simply ten connections, and every tool takes the connection by name.

Related MCP server: hcloud-mcp

Quick start

The shortest working setup is one environment variable:

export HETZNER_TOKEN=<your Hetzner Cloud API token>
npx @donedynamics/hetzner-mcp install

install detects the MCP clients on your machine — Claude Code, Claude Desktop, Codex, Cursor, Zed, opencode, Kimi, MiniMax — shows you exactly what it will write, and writes only what you approve. It writes a pointer: a command and at most a connection name. It never writes a credential into a client config.

npx @donedynamics/hetzner-mcp install --dry-run   # show the diff, change nothing
npx @donedynamics/hetzner-mcp install --pin       # pin the exact version
npx @donedynamics/hetzner-mcp doctor              # what is configured, and what is wrong with it

Several projects, several accounts

Put the name in the variable and you have a second connection:

export HETZNER_TOKEN_PROD=...        # connection "prod"
export HETZNER_TOKEN_STAGING=...     # connection "staging"
export HETZNER_ACCOUNT_TOKEN=...     # connection "account"  (Storage Boxes)

Every tool then takes connection: "prod", and find_resources takes connection: "*" to search all of them at once. With exactly one connection configured, the parameter does not exist at all — there is nothing to choose.

For per-connection settings — a read-only production connection, a credential from 1Password, a longer timeout — use a config file. Full reference: docs/connections.md.

{
  "version": 1,
  "defaultConnection": "prod",
  "connections": {
    "prod": { "tokenEnv": "HZ_PROD", "readOnly": true },
    "prod-write": { "tokenCommand": ["op", "read", "op://Infra/hcloud/credential"] },
    "storage": { "surface": "hetzner", "tokenEnv": "HZ_ACCOUNT" }
  }
}

Credentials cannot go in that file. The schema has no token property and rejects unknown keys, so writing one is a startup error that tells you the three places it can live instead.

Three surfaces

Hetzner is not one API, and this server does not pretend otherwise:

The surface is always visible, because a cloud server is a virtual machine billed by the hour and a robot server is leased physical hardware on a monthly contract with a cancellation period. Merging those two into one word is how "reboot the server" becomes a question nobody can answer safely.

You never configure an address. Hetzner runs exactly one instance of each API, so it is derived from the surface — a value you could type there could only repeat what the server already knows, or be wrong.

The tools

Most of this API is asynchronous

144 of Hetzner's 221 operations return an Action rather than a result: the call returns {action: {status: "running"}} and the work happens afterwards. So waiting is the default here rather than a convenience, and every response says in meta.action.awaited whether the work actually finished or the wait gave up. A tool that reported a running Action as done would be worse than one that never waited, because you could not tell.

Safety

Deletes are off by default. execute_destructive_operation is not registered unless HETZNER_ALLOW_DESTRUCTIVE=true — not listed-and-refusing, absent. Nothing in tools/list then carries destructiveHint: true, so a host that auto-approves non-destructive tools is auto-approving something genuinely non-destructive.

Four operations are destructive without being deletes, and the build fails if any of them stops matching: rebuilding a server, importing a zone file, replacing a record set, and rolling a Storage Box back to a snapshot.

Read-only is a ceiling. HETZNER_READ_ONLY=true, or readOnly on one connection, refuses every non-GET at the HTTP client before the socket opens. A connection cannot opt back out of it.

No tool schema can name a host. There is no baseUrl, url, host or credential parameter anywhere. connection is an enum over the names you configured. An injected instruction to point at another server has nowhere to land.

One thing to know before you use writes

Operations that open a bill are not gated. With a write-capable connection, provisioning a server is reachable without any additional flag. The server makes the cost visible rather than absent — search_operations marks those operations costly, and a call that created something reports Hetzner's published price in meta.billing.

That is a real mitigation for a model reasoning in good faith and not a mitigation against prompt injection. If it is the wrong trade for you, use a read-only Hetzner token, or readOnly: true, and keep writes on a separate connection you name explicitly.

The full threat model is in SECURITY.md, including the parts where the news is not good.

Environment reference

Documentation

• docs/connections.md — connections, credentials, precedence

• SECURITY.md — threat model and recommended posture

• docs/clients/ — per-client installation notes

• CHANGELOG.md

Development

npm install
npm test          # 1238 tests
npm run typecheck
npm run codegen   # regenerate the catalog from the vendored OpenAPI specs
npm run build

The catalog is generated from Hetzner's own OpenAPI specifications, which are vendored into scripts/ and committed. Every MCP client spawns this process fresh, so parsing 3.4 MB of spec on each start — or fetching it — would be worse than a file in git. CI regenerates and diffs, so an upstream change breaks the build loudly instead of shipping a stale tool surface.

Contributions welcome — see CONTRIBUTING.md.

License

MIT