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

Annotations already state readOnlyHint=true and destructiveHint=false; the description reinforces this by declaring the tool only explains steps and creates nothing. That negative scope disclosure is the most valuable behavioral fact here, though no rate limits, auth expectations, or returned content shape are described.

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 sentences, no filler, and the non-actions are listed where the agent will read them. The lead phrase is slightly padded but not wasteful.

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 zero-parameter, read-only guidance tool with no output schema and safety already covered by annotations, the description supplies enough: what it explains and what it deliberately does not do. It stops short of saying what the agent receives back or what to do after reading the steps.

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 tool takes zero parameters, so the baseline is 4 and there is no parameter meaning for the description to add. Nothing in the text misleads about inputs.

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 the resource (Voidly Agent Home setup) and, more usefully, narrows the actual action to explaining local key/signing steps and a mailbox command, which separates it from voidly_home and voidmail_setup. The opening phrase 'Start private ... setup' is vague on its own and only gets clarified by the second sentence.

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 gives an explicit when-not: 'does not register an agent, create a wallet or mailbox, or publish a profile,' which steers the agent away from expecting provisioning side effects. It never names the sibling tool to use for those operations (e.g. voidmail_setup), so the routing is implicit rather than complete.

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