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

Annotations declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the mutation profile is already known; the description adds the required 'listings:write' scope and the consequence ('A proven owner can't have the listing taken over'). It does not say whether calling twice issues a second token or invalidates the first, which matters given idempotentHint=false.

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 compact sentences: action, workflow/next step, safety consequence, permission requirement. No filler, and the core action is front-loaded before the conditional guidance.

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 two-parameter, non-destructive mutation with an output schema and full schema coverage, the description covers the essentials: permission scope, what is returned, and the required follow-up call. The remaining gap is token lifetime and re-invocation behavior.

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 100% and the schema already lists dns_txt, html_file and meta_tag, so the description's repetition of the same three values adds little. The only extra signal is that the chosen method determines where the token must be placed, which is a return-value hint rather than parameter semantics.

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?

States a specific verb and resource ('Start proving the person controls a listing's website') and names the three methods plus what comes back ('a token and exactly where to put it'). It also implicitly separates itself from the sibling verify_ownership, which it names as the follow-up step.

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?

Gives an explicit conditional workflow: 'If you can deploy the site or edit its DNS, place it, then call verify_ownership.' That tells the agent both the precondition and the next tool. It stops short of saying what to do when the caller cannot deploy or edit DNS, so the alternative path is left to inference.

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