Create a Hetzner Cloud firewall with custom inbound and outbound rules, labels, and resources to control network traffic. Apply rules to servers or label selectors.
| Name | Required | Description | Default |
|---|---|---|---|
| body | Yes |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the mutation profile is covered. The description adds genuine value beyond that with a table of operation-specific 422 errors (server_already_added, incompatible_network_type, firewall_resource_not_found), which tells an agent what failure modes to expect. It still omits what the call returns, whether the firewall is created unattached, and any auth/permission context.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The error table is compact and useful, but the opening two lines ('Create a Firewall' followed by 'Create a Firewall') are pure duplication with no informational payload. The useful content (error codes) is not front-loaded.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a create tool with a deeply nested body and no output schema, the description should at minimum say what is created and returned and how the firewall is attached. It covers failure modes well but leaves the success path and the apply_to attachment behavior entirely to the schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Top-level schema description coverage is 0% — the single 'body' parameter has no description — and the description does not compensate by explaining the request body at all (name uniqueness, rules limits, apply_to semantics). The nested properties are well documented in the schema itself, but the description contributes nothing about parameters.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific verb and resource ('Create a Firewall'), which is unambiguous against the many get/list/update siblings. However, the first two lines merely restate the tool name and title, and there is no explicit differentiation from related creation tools (hcloud_create_network, hcloud_create_server) or from hcloud_firewall_set_rules_action.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this tool versus alternatives such as hcloud_apply_firewall_to_server or hcloud_firewall_apply_to_resources_action, and no prerequisites are mentioned. Usage is only implied by the verb 'Create'.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.