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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely new behavioral context: USD currency, cheapest-printing basis per collector number, parity with the set page figure, the 25/10 result caps, and that master set totals are labeled separately from companion sets. Only return-shape and pagination/caching behavior are unstated.

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?

Front-loaded with the use case, then the return contents, then the ID dependency — a sensible ordering with no filler sentences. It is dense and long-sentenced, though every clause (basis, currency, caps, subset handling) contributes distinct information.

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 one-parameter, read-only, idempotent tool with an output schema and full schema coverage, nothing an agent needs to call it correctly is missing: trigger conditions, ID source, and the exact scope of what is priced are all stated.

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 100% and there is a single required integer parameter, so the schema already carries the load. The description still adds value by stating the parameter's origin ('Needs a group_id from search_cards'), confirming it is a set identifier rather than a card or product id.

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 gives a precise verb-plus-resource picture: it returns set-level price totals (completion cost, master set total, top 25 singles, 10 sealed products, companion subsets). That aggregate framing implicitly separates it from card-level siblings like card_price and sealed_prices, but it never names those siblings explicitly.

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?

It gives concrete user-intent triggers: 'when the user asks what a set is worth, what it costs to complete, or which cards in one set are the most valuable,' plus the prerequisite that group_id comes from search_cards. There are no explicit exclusions (e.g., 'for a single card use card_price'), so it stops short of a 5.

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