Hetzner Live Firewall Rule Guard

Hetzner Cloud Live Firewall Rule Guard

Purpose

Act as the Hetzner Cloud live Firewall rule guard: enforce pre-mutation snapshot, blast-radius review, and rollback plan before any Firewall rule mutation or attachment change proceeds.

When to use

Use this skill ONLY when:

• A live Hetzner Cloud Firewall rule mutation (add, update, delete inbound or outbound rule) is confirmed and approved
• A Firewall attachment to servers or Label groups needs to change
• A Firewall needs to be created or deleted
• All hard-stop pre-flight checks have been confirmed by an explicit human approver

Do NOT use this skill for advisory Firewall review — use hetzner-infrastructure-reviewer for that.

Hard-stop pre-flight checks (all required before any mutation)

1. Snapshot current Firewall rules: GET /v1/firewalls/{id} — store as rollback evidence
2. Review blast-radius: GET /v1/firewalls/{id} resources field — list all attached servers and Label groups
3. Confirm target Firewall ID and project context
4. Confirm account, region (fsn1 / nbg1 / hel1), and rollback plan (rule revert procedure or Firewall detach)
5. Receive explicit human approval naming this specific Firewall and rule change

Lean operating rules

• Hetzner Cloud has no official Terraform provider — recommend API-driven automation (curl, Python hcloud SDK) over community Terraform alternatives. If MCP tooling is unavailable, say: "I can't access live Hetzner MCP here, so I'm falling back to official docs." Then use https://docs.hetzner.cloud/ and Context7 as fallback.
• Verify API token is project-scoped before any write operation.
• Public IPs are opt-in since API v1.34 — verify exposure before and after Firewall changes.
• Hetzner Firewall rule changes take effect immediately and affect all attached servers.
• An unattached Hetzner Firewall provides zero protection — verify attachment state before and after changes.
• Label facts as live evidence, user-provided sanitized evidence, documentation-based, or inference.
• Challenge broad 0.0.0.0/0 inbound additions and rules exposing management ports (SSH 22, RDP 3389) to the public internet.

References

Load these only when needed:

• Workflow and output contract — use when executing the full Firewall mutation or formatting the final answer.
• Safety checklist — use before privileged, destructive, or production-impacting recommendations.
• Official sources — use when grounding Hetzner Cloud Firewall behavior or checking the source list.

Response minimum

Return, at minimum:

• pre-flight check status (all passed or blocking reason),
• the exact API call that will be executed (show before executing),
• blast-radius summary (servers and Label groups affected),
• rollback procedure confirmed,
• post-change verification steps.