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 adds genuinely non-obvious behavior: an empty result is not proof of non-support, and payment observations are not acceptance guarantees, which prevents the agent from over-reading 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?

Four sentences, front-loaded with the usage trigger, then capabilities, then two caveats. Every sentence carries information; only the 'Review filters match the same reported attempt' clause is cryptic without further context.

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 an 11-parameter, zero-required, no-output-schema search tool, the description covers purpose, triggers, facets and result-interpretation caveats, which is most of what an agent needs. It does not describe result shape or pagination behavior, leaving a small gap given there is no output schema.

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 burden and largely delivers: it maps out q/name/domain/category/country/paymentMethod/outcome/blocker/inferenceEffort as searchable facets. It omits pagination (limit, offset) and gives no syntax or matching-semantics hints for those filters.

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 clear verb+resource ('find merchants') and enumerates the searchable facets (name, domain, keywords/category, country, payment method, outcome, blocker, inference effort), so the agent knows exactly what this tool retrieves. It does not explicitly differentiate itself from the singular sibling get_merchant, which keeps it at 4 rather than 5.

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?

Gives explicit triggering conditions: 'Use before an online purchase or after a blocked checkout to find alternatives,' which tells the agent when this tool is the right call. It also guards against misreading empty results and advises broadening the query, but names no alternative tool for those cases.

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