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

Annotations already declare read-only, idempotent, non-destructive behavior, so the safety profile is covered. The description adds genuine behavioral context beyond that: pricing is age-conditional ('when an age is given') and the response includes premium projections every five years out to twenty years, which shapes how an agent interprets 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?

A single dense sentence that front-loads the resource and then the returned fields. It is efficient with no filler, though the trailing clause about five-to-twenty-year projections is slightly compressed and takes a second read.

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, return format needn't be described, and annotations cover the safety profile, so the description's job is narrower. It covers what the tool does and the key pricing behavior, but omits guidance on when to prefer it over sibling pricing tools.

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 75%, so the schema already documents cert, gender and smoker. The description adds meaning for the undocumented age parameter ('priced at this age when an age is given'), clarifying it is optional and changes the output, but adds nothing beyond the schema for the other three. Baseline 3 for high coverage is appropriate.

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 names the resource (every option sold under one certification number) and enumerates the fields returned (room class, deductible, area) plus the pricing behavior, so the agent knows exactly what this returns. It does not explicitly differentiate from siblings like price_plans or compare_plans, which is the only thing keeping it from a 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?

Usage is implied: you need a cert (from an earlier result) and optionally an age to get age-priced figures. However, there is no explicit when-to-use vs. when-not, and no mention of the closest alternatives (price_plans, compare_plans), so the agent must infer the routing.

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