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

Annotations cover read-only and open-world behavior, and the description adds context beyond them: the service is free and capped at 10 checks per IP per day, which materially affects retry strategy. It does not say what happens on an unreachable URL or how failures are reported.

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?

Front-loaded with the purpose and scope; the nine-item checklist is long but earns its place since there is no output schema to describe the returned checks. No filler sentences.

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?

Because there is no output schema, the enumerated checklist is essential and present, and the rate limit is disclosed. Minor gaps remain: no indication of result format (pass/fail per check) or behavior on error, but nothing that would prevent an agent from calling it correctly.

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 one parameter at 100% schema coverage plus an inline example ('yourbusiness.com'), the schema carries the load. The description adds only a mild constraint ('one small business homepage'), implying the URL must be a homepage rather than a deep link, but no format rules beyond the schema's own example.

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 ('check') and a precisely scoped resource ('one small business homepage'), then enumerates the nine checks so the agent knows exactly what the tool inspects. This is clearly distinct from siblings like request_redesign or live_numbers without needing to name them.

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?

'One small business homepage' and 'Up to 10 checks a day for each IP address' establish scope and a hard rate limit, which implicitly tells the agent when the tool applies. However, there is no explicit guidance on when to use this over the sibling tools or what to do when the daily quota is exhausted.

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