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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description still adds real value beyond them: reviewer names and profiles are never returned, and only public data is read — both material expectations an agent would otherwise have to discover empirically.

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 short sentences, front-loaded with purpose and lookup key, then return contents, then privacy constraints. Every clause carries information and nothing is repeated from the schema.

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 enumerating exactly what comes back (TrustScore, star rating, total count, and per-review rating, title, text, date, company reply). Combined with the required domain key and the privacy constraint, an agent has everything needed to call it and interpret results.

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%, so all five parameters (including the sort enum, limit range, stars filter and language) are already documented in the schema. The description only restates the domain example, adding no semantics for filters or ordering — baseline 3 is appropriate.

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 ('Read the public Trustpilot rating and reviews of a company') and names the exact lookup key ('by its website domain, e.g. "zalando.de"'). This cleanly separates it from the sibling google_maps_get_reviews, since the data source is named explicitly in the first clause.

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 description implies the use case (fetching Trustpilot reputation data for a domain) but never states when to prefer it over google_maps_get_reviews or what happens when a company has no Trustpilot presence. No explicit when-not or alternative-routing guidance is given, which is a notable gap given a review-reading sibling exists.

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