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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint). The description adds genuinely non-structured context: 10 results per page and a $0.005 per-request billing rate, which matters for cost-aware agent planning. It stops short of describing pagination limits or rate limiting, so not a 5.

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 core action, then filters, page size, alternative tool, and cost in a compact sequence. The enumerated return-field list is the one slightly bloated part, but it substitutes for a missing output schema and so earns its space.

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 usefully enumerates the returned fields (business_unit_id, name, domain, TrustScore, stars, review count, categories, location) and covers paging and cost. An agent has everything needed to call and interpret results 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% with enum values documented for min_rating and min_review_count, so the schema carries parameter meaning. The description's 'filter by minimum rating and review count' restates that rather than adding syntax or behavioral nuance, so baseline 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?

States a specific verb (search) and resource (Trustpilot companies) plus the query semantics ('by name or keyword'), which separates it from search_trustpilot_categories and trustpilot_category_companies. An agent can identify the tool without opening the schema.

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?

Explicitly routes the agent to trustpilot_company_reviews when it wants a company's reviews, which is a real disambiguation. It does not, however, contrast itself with the other Trustpilot siblings (search_trustpilot_categories, trustpilot_category_companies), so it falls short of full when/when-not coverage.

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