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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description still adds specifics beyond them ('never write, send email or submit an enquiry') and discloses regulatory context (unlicensed referrer, referral fee, licensed HK broker, Mainland signing requirement) that an agent could not infer from structured fields.

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 capability statement is correctly front-loaded, but the following four sentences are largely compliance boilerplate (referral fee, licensing, signing location) that does not help an agent select or invoke the tool, and the final clause restates the readOnly annotation.

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 compensates by naming what is returned, and annotations cover the safety profile. The remaining gap is that one of three parameters ('limit') is undocumented anywhere, but overall an agent has enough to call 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?

Schema description coverage is 0%, so the description carries the load. It does map the locale enum to 'EN/Traditional/Simplified Chinese', which is genuine added meaning, but says nothing about the 'query' string constraints or the 'limit' parameter's role.

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 ('Search published EN/Traditional/Simplified Chinese guides') plus the return shape ('titles, URLs and answer snippets'). The scope boundary ('General information only; no product recommendation...') implicitly separates it from compare_products, but no sibling is named explicitly.

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?

The exclusions ('no product recommendation, suitability assessment or best ranking') clearly tell the agent when this tool is the wrong choice, which is real usage guidance. It stops short of naming the alternative tool an agent should route to instead.

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