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

Annotations already declare the operation read-only, and the description adds useful behavior: it returns every option under one cert and shows pricing at the supplied age plus premium projections in five-year steps to twenty years. This goes beyond the annotations and schema, though it doesn't address ordering, filtering, or error conditions.

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?

The description is a single compact sentence that front-loads the key scope ('Every option sold under one certification number') and then packs the useful details. It is slightly dense and grammatically awkward, but no word is wasted.

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?

Given the readOnlyHint, the optional age parameter, and a rich output schema, the description says enough about what the caller gets and the projection cadence. It does not discuss edge cases such as missing age or null cert, but those are relatively minor for this tool.

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 descriptions already cover cert, gender, and smoker well (75% coverage). The description adds meaning mainly for age, clarifying that it controls the displayed current price and the projection horizon. That is helpful but not comprehensive, so it doesn't clearly rise above the baseline.

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 identifies a specific resource (one certification number) and the output content (all options with room class, deductible, area, current and projected premiums), so an agent can tell it returns a comprehensive option list for a single plan. It lacks an explicit verb and does not call out sibling tools, so it falls short of 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?

There is no guidance about when to choose plan_options over related tools such as price_plans, compare_plans, or plan_coverage, and no exclusions or prerequisites are stated. The only conditional clause ('when an age is given') describes parameter behavior, not usage context.

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