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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuinely new operational context: 20 results per page and a $0.005 per-request billing cost, which matters for an agent deciding whether to page through results.

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 description is dense and front-loaded: what it returns, then filters/sort, then pagination, then how to find slugs, then cost. Every sentence carries information, though the mid-sentence filter list is slightly cluttered.

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 the returned fields (name, domain, TrustScore, review count, categories, location, category size and subcategories) and supplies pagination limits, slug-discovery guidance and billing cost. An agent has everything needed to call and interpret 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 100%, so every parameter including defaults, enum values and the ISO country code format is already documented. The description restates the filter and sort options without adding syntax or semantics beyond the schema, so the baseline of 3 applies.

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?

The description gives a specific verb and resource ('List the companies in a Trustpilot category by category slug or URL'), which is immediately distinguishable from search_trustpilot_companies or trustpilot_category_details. It does not, however, explicitly differentiate itself from the close sibling trustpilot_category_newest or clarify how it relates to trustpilot_category_details.

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?

It states the filtering and sorting conditions (country, minimum rating, claimed status; recommended or recently reviewed) and routes the agent to search_trustpilot_categories plus an external doc URL for obtaining the required category_id. It stops short of saying when to prefer this over trustpilot_category_newest or the category search siblings.

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