Add a subnet to an existing Hetzner Cloud network; provide the network ID and subnet type, or omit the IP range to auto-select the first available /24.
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | ID of the Network. | |
| body | Yes | ||
| wait | No | Poll the resulting action until success/error or timeout. |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already flag this as a non-readonly, non-destructive, open-world mutation, so the description adds real value on top: it discloses the default /24 allocation when ip_range is omitted and the conflict failure mode when a change is in flight on the Network. It doesn't mention that polling is controlled by `wait` or what the async action returns, but the behavioral picture is substantially better than the annotations alone.
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?
Three short sentences, front-loaded with the core action, then default behavior, then the failure case — every sentence carries information. The repeated markdown anchor links are mild noise but not distracting.
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 mutation action with nested body params and no output schema, the description covers the action's purpose, the default-allocation behavior, and the conflict condition, which is enough for correct invocation. Prerequisites (Network must exist, parent IP range constraints) are left 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?
Schema coverage is 67%, between the high and low baselines. The description supplies important semantics the schema lacks for `ip_range` (omitting it triggers automatic /24 selection), but says nothing about `type`, `vswitch_id`, or the `wait` polling flag, so it only partially compensates for the coverage gap.
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 gives a specific verb and resource ('Add a subnet to a Network') and names the target Network, which cleanly separates it from siblings like hcloud_network_add_route_action or hcloud_network_delete_subnet_action. It doesn't explicitly reference a sibling, but the operation is unambiguous.
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?
Usage is implied by the operation itself, and the note about the conflict error tells the agent when a call will fail, but there is no explicit 'use this instead of X when Y' guidance among the many network/route/subnet siblings.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.