Hetzner Cloud MCP Server

Instructions

Set rules for a firewall.

Sets the rules of a firewall. All existing rules will be overwritten.
Pass an empty rules array to remove all rules.

Example:
- Set rules: {"firewall_id": 12345, "rules": [{"direction": "in", "protocol": "tcp", "port": "80", "source_ips": ["0.0.0.0/0"]}]}

Implementation Reference

• mcp_hetzner/server.py:794-842 (handler)

  The handler function for the 'set_firewall_rules' MCP tool. It retrieves the specified firewall, converts the provided rule parameters into hcloud FirewallRule objects, applies the rules using the Hetzner API client.firewalls.set_rules(), and returns the resulting actions.

  def set_firewall_rules(params: SetFirewallRulesParams) -> Dict[str, Any]:
      """
      Set rules for a firewall.
      
      Sets the rules of a firewall. All existing rules will be overwritten.
      Pass an empty rules array to remove all rules.
      
      Example:
      - Set rules: {"firewall_id": 12345, "rules": [{"direction": "in", "protocol": "tcp", "port": "80", "source_ips": ["0.0.0.0/0"]}]}
      """
      try:
          firewall = client.firewalls.get_by_id(params.firewall_id)
          if not firewall:
              return {"error": f"Firewall with ID {params.firewall_id} not found"}
          
          # Convert rule parameters to FirewallRule objects
          rules = []
          for rule_param in params.rules:
              rule = FirewallRule(
                  direction=rule_param.direction,
                  protocol=rule_param.protocol,
                  source_ips=rule_param.source_ips,
                  port=rule_param.port,
                  destination_ips=rule_param.destination_ips,
                  description=rule_param.description
              )
              rules.append(rule)
          
          # Set the rules
          actions = client.firewalls.set_rules(firewall, rules)
          
          # Format the response
          return {
              "success": True,
              "actions": [
                  {
                      "id": action.id,
                      "status": action.status,
                      "command": action.command,
                      "progress": action.progress,
                      "error": action.error,
                      "started": action.started.isoformat() if action.started else None,
                      "finished": action.finished.isoformat() if action.finished else None,
                  }
                  for action in actions
              ] if actions else None,
          }
      except Exception as e:
          return {"error": f"Failed to set firewall rules: {str(e)}"}

• mcp_hetzner/server.py:205-208 (schema)

  Pydantic BaseModel defining the input schema for the set_firewall_rules tool, including firewall_id and rules list.

  class SetFirewallRulesParams(BaseModel):
      firewall_id: int = Field(..., description="The ID of the firewall")
      rules: List[FirewallRuleParam] = Field(..., description="List of firewall rules")

• mcp_hetzner/server.py:177-183 (schema)

  Pydantic BaseModel defining the structure for individual firewall rules used in set_firewall_rules.

  class FirewallRuleParam(BaseModel):
      direction: str = Field(..., description="Direction of the rule (in or out)")
      protocol: str = Field(..., description="Protocol (tcp, udp, icmp, esp, or gre)")
      source_ips: List[str] = Field(..., description="List of source IPs in CIDR notation")
      port: Optional[str] = Field(None, description="Port or port range (e.g., '80' or '80-85'), only for TCP/UDP")
      destination_ips: Optional[List[str]] = Field(None, description="List of destination IPs in CIDR notation")
      description: Optional[str] = Field(None, description="Description of the rule")

• mcp_hetzner/server.py:794-794 (registration)

  The @mcp.tool() decorator registers the set_firewall_rules function as an MCP tool.

  def set_firewall_rules(params: SetFirewallRulesParams) -> Dict[str, Any]: