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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context on top: the currency (USD), the three billing cadences returned, and the fact that no account or authentication is required. It stops short of describing result shape or whether the catalog is exhaustive, which keeps it below 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?

Two short fragments totalling under fifteen words, with the resource and currency front-loaded and the access precondition last. Every clause carries information; nothing is padding.

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 zero-argument read-only lookup with no output schema, an agent needs to know what comes back and whether any setup is required; the description answers both (plans and prices in USD across three cadences, no account needed). Only the absence of any note on result shape or freshness keeps it from being fully complete.

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, which sets the baseline at 4. The description correctly adds no parameter talk and instead spends its words on what the output covers, so nothing is misleading.

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 and its content precisely: current plans and prices, quoted in USD with monthly/yearly/one-time cadences. That is specific enough to separate it from get_company_info and search_site, though it never uses an explicit verb like 'list all plans', so the retrieval framing is implied rather than stated.

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 only implied: an agent should call this when it needs pricing or plan information. The 'No account needed' clause usefully signals there is no auth prerequisite, but there is no explicit when-to-use rule and no reference to when a sibling such as get_company_info would be the better call.

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