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

It discloses the underlying API call (PUT /1.3/server/{uuid}), the accepted simple_backup grammar including UTC interpretation, and the disabling value 'no' — context the annotations do not carry. The 'reversible fields' claim sits in mild tension with destructiveHint=true, but since renaming and backup-schedule changes are recoverable, this is a conservative annotation rather than a contradiction.

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 tightly packed sentences, front-loaded with the action and its scope, then exclusions, then the backup format. No filler sentences; every clause adds operational value.

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?

With no output schema, the description covers the mutation surface, the exclusion boundaries, the backup string format, and the API endpoint — enough for correct invocation. It does not describe return values or whether partial updates are supported, which is a minor gap.

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 description coverage is 100%, so the baseline is 3, but the description adds meaning the schema lacks: the UTC timezone for simple_backup and the semantics of 'no' to disable. The server_uuid parameter is only implied ('a server's'), not explicitly called out.

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 names a specific verb (Change) and the exact resource fields (title, hostname, simple-backup schedule), and explicitly contrasts with what it does not do. An agent can distinguish it from start/stop/restart and get_server siblings without opening any schema.

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 clearly scopes usage with explicit exclusions ('no resizing or plan change (billing) and no firewall toggle'), which steers the agent away from misuse. It lacks an explicit pointer to a sibling alternative (e.g. when to use get_server first), so it stops short of full when/when-not/alternatives guidance.

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