change_vps_hostname

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Despite the annotations only saying readOnly=false, destructive=false, etc., the description discloses the real side effect: it rewrites files on the offline disk image and is unsafe on a running VPS. It also surfaces the mandatory confirm=true guard. No contradiction with annotations.

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?

Two dense sentences: main action up front, then the critical precondition and confirmation requirement. No filler or repeated schema information.

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 three-parameter mutation with no output schema, the definition supplies the core operation, the prerequisite, the safety rationale, the first-to-call sibling, and the guard flag. Nothing needed to invoke it correctly is missing.

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?

With 0% schema description coverage, the description must carry parameter meaning. It does for the two key ones: hostname is what is being changed and confirm must be true despite the schema default of false. It does not explicitly describe vps_id, but its role is clear from 'a VPS's' and the schema.

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 opens with 'Change a VPS's hostname,' a specific verb+resource statement that exactly identifies the operation and distinguishes it from sibling mutations like change_vps_root_password or resize_vps. It goes beyond the tool name by adding the offline-disk-image context.

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?

It explicitly states the prerequisite ('The VPS must already be stopped'), explains why (rewrites files on the offline disk image), and names the tool to call first ('stop it first with stop_vps'). This is clear when-to-use guidance and a concrete alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.