Set hostname

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

Annotations already mark the operation as destructive and idempotent. The description adds meaningful behavioral context beyond annotations by warning that changing the hostname does not automatically update the PTR record and that A/AAAA records must point to the VM IP for hostname reachability. This helps an agent anticipate side effects.

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 description is compact and front-loaded with the core purpose. The DNS/PTR caveats and the explicit use statement are useful additions rather than filler. It could be slightly tighter, but every sentence contributes meaningful 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 simple two-parameter mutation tool with annotations and no output schema, the description covers the key operational concerns: what the endpoint does, what it does not do automatically, and what else is needed for hostname reachability. Minor gaps remain around hostname validation and whether the previous hostname is replaced, but these are not critical for basic invocation.

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?

The input schema has 100% description coverage for both parameters, so the schema carries most of the burden. The description adds a little semantic context by framing the hostname as a 'custom hostname' and implying it should be resolvable via DNS, but it does not specify format, length, allowed characters, or how virtualMachineId is used beyond 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 a specific verb and resource: 'Set hostname for a specified virtual machine.' It further clarifies the purpose by saying it configures custom hostnames for VPS instances, which distinguishes it from sibling tools like VPS_resetHostnameV1 that imply resetting rather than setting custom values.

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?

The description provides an explicit use statement: 'Use this endpoint to configure custom hostnames for VPS instances.' It also supplies relevant operational context about DNS/PTR requirements, but it does not explicitly contrast this with alternatives such as VPS_resetHostnameV1 or other VPS configuration endpoints.

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