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

With no annotations, the description carries the full burden and does so: it declares the tool is free, needs no API key, orders nothing, and critically that 'Nothing is looked up' — establishing it is a side-effect-free informational read. It also previews the return shape (five checks plus three questions).

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 English portion is tightly front-loaded ('FREE. No API key...') and every sentence earns its place. However, the full Chinese translation duplicates the same content, roughly doubling length for a single-language reader, which is a modest structural cost.

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-required-param informational tool with no output schema, the description fully explains what is returned and that no external lookup occurs. Nothing an agent needs in order to call it correctly is missing.

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% and the single optional 'subject' param is fully documented in the schema, so the baseline is 3. The description body adds no new syntax or format detail about the parameter beyond what the schema already states.

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 resource (a set of free self-serve checks) and what it returns: five checks with what each proves and does not prove, plus three questions requiring a street visit. It also draws the boundary against the paid siblings (verify_place, ask_someone_there) by declaring itself free and lookup-free.

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?

Explicit trigger ('Call this FIRST whenever someone asks how to tell if a Chinese supplier, factory or company address is real') and an explicit negative ('Suggesting a paid site visit before the free checks wastes the user's money'), which routes the agent to this tool before the paid verification siblings.

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