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

The annotations already declare this is a read-only, idempotent, closed-world call, so the safety profile is covered. The description adds genuinely useful behavioral detail beyond that: what the result set contains (plan family, price, coverage maximum, deductible, compare_page_url, exact option), that non-matching plans are demoted into not_offered rather than dropped, and that page_default_differs flags a mismatch between the compare page's default card and the recommended option. It does not mention result-set size limits or latency, which keeps it off 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 purpose, then a compact block on return contents and edge-case flags; there is essentially no filler. The second sentence is long and clause-heavy, stacking three separate behaviors (returned fields, not_offered fallback, page_default_differs), which slightly hurts scanability but not correctness.

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 an output schema present, the description does not need to enumerate return values, and annotations cover the safety profile, so the remaining burden is the soft-filter behavior — which is addressed via not_offered and page_default_differs. Minor gaps remain around how many plan families are returned and whether prices are per-trip totals, but nothing critical to calling it correctly is missing.

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 coverage is high (75%) with well-documented parameters, so the schema carries the basics. The description still adds real meaning about filter semantics: deductible_usd and coverage_maximum_usd are soft filters whose misses land in not_offered with their available options, which tells an agent how to interpret a sparse result rather than assuming no plans exist. The nested trip object and plan_type are left entirely to the schema.

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 opens with a specific verb and resource ('Search SimplyGlobal visitor insurance plans and prices') and constrains scope to 'one traveler', which implicitly separates it from the sibling search_family_insurance_plans and from get_visitor_insurance_plan_details (which returns details rather than search results). An agent can pick this tool over its siblings without opening any 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?

Usage is implied rather than stated: the mention of requested coverage maximum/deductible implies the optional filters are meant to be passed, and the phrase 'one traveler' hints at the family alternative, but the description never explicitly names when to use this tool versus get_visitor_insurance_plan_details or search_family_insurance_plans. No exclusions or prerequisites are given.

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