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

Annotations already cover read-only, idempotent, open-world, so the bar is lower, but the description adds genuinely new operational context: which calls are charged (only 2xx answers), that missing parameters and no-data items are free, and that empty search results still cost. Retention and refunds are named as topics but not elaborated, and no auth or rate-limit details are given.

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 front-loaded sentence opens with the cost signal 'FREE.' and then packs the charge rules, retention, and refunds into one parenthetical clause. It is dense but every clause carries information; only the compressed parenthetical slightly hurts readability.

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 a no-parameter informational tool with no output schema, the description states what topics are returned and the key billing behavior. Return format and how the terms are structured are unspecified, but an agent has enough to decide to call it and know what it will get.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline applies. The description correctly adds no parameter text and spends its space on behavioral content instead.

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?

Names the resource (service terms) and enumerates the substance it returns: charging rules, retention, and refunds. An agent can tell this is a policy/pricing-information tool rather than a data lookup, though the verb is implicit and the title merely restates the name.

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?

The leading 'FREE.' signals cost but is not explicit when-to-use guidance, and no alternative or precondition is named. An agent must infer that it should consult this tool to understand billing before or after calling chargeable siblings.

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