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

Annotations already establish readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds business-critical context not present in structured fields: prices are in USD, all payments are one-time, and nothing renews — the last point materially shapes how an agent communicates cost to a user. It stops short of describing the shape of the listing (e.g., per-pack rows with names and amounts).

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 sentences with zero filler, and the most decision-relevant fact (USD, one-time, no renewal) is front-loaded. Nothing is repeated from the title or annotations.

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 simple zero-parameter lookup with no output schema, the description supplies enough — what is priced, in what currency, and the billing model — for an agent to call it and set user expectations. It could add one clause on what the response contains (a list of packs/top-ups with amounts), which is the only real gap.

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 no parameters, so there is nothing for the description to disambiguate; baseline for a zero-parameter tool is 4. The USD mention is the only semantic detail, and it applies to the values rather than to inputs.

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 contents (DatingProfile packs and top-ups, priced in USD), which distinguishes it from siblings like buy_pack or account_status. It lacks an explicit verb such as 'returns prices for,' so the agent must infer that this is a read-only price lookup rather than a purchase action, but the intent is unambiguous in context.

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 can infer it should call this to see costs before calling buy_pack, but the description never states that relationship or names any alternative. With zero parameters and a read-only profile the gap is low-risk, but no explicit when-to-use or when-not-to-use guidance is given.

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