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

Annotations already declare this a read-only, idempotent, non-destructive lookup, so the safety profile is covered. The description still adds real behavioral context: it returns links only, it never touches private orders or personal records, and the policy_specimen service exists only for WorldTrips Atlas Travel. It does not mention behavior on a missing or unresolvable plan, which is the one identifiable gap.

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?

Two sentences, front-loaded with the resource and its three services before the lookup mechanics and the exclusion list. The first sentence is dense with em-dash clauses, but every clause carries distinct information and nothing is repeated from the schema verbatim.

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?

The tool is a simple read-only link resolver with a full input schema, an output schema, and complete annotations. The description covers the lookup paths, the service scope, the one carrier-specific exception, and the negative intents, so nothing an agent needs in order to call 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 100%, so the baseline is 3. The description adds meaning beyond the schema by explaining that plan_id alone resolves both carrier and plan name, and that carrier and plan_name form an alternative lookup path, plus the service-specific Atlas Travel constraint that the enum alone does not convey.

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 ('Return the insurer's official public pages for a visitor insurance plan') and enumerates the exact three services it resolves, including the WorldTrips Atlas Travel restriction on policy specimens. An agent can distinguish this from search_visitor_insurance_plans and get_visitor_insurance_plan_details without opening a 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 tells the agent how to locate the plan (plan_id from search_visitor_insurance_plans, or carrier plus plan_name) and explicitly rules out adjacent intents: filing a claim, checking claim status, judging coverage or eligibility, confirming network participation, and looking up personal records. That is a strong when-to-use and when-not-to-use contract.

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