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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safe read nature is covered. The description adds the login requirement and the account_link_id matching nuance, which is useful beyond annotations. However, it does not describe potential side effects, rate limits, or error conditions, though these are less critical for a read-only pagination tool.

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 brief and front-loads the critical prerequisite (login requirement) before describing the action. Two sentences with no fluff. It efficiently conveys the required state and the tool's purpose, though it could structure the requirement more formally.

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 pagination tool with a search context and page number, the description covers the essential prerequisites: login and prior search context. The schema documents parameters, and annotations cover the safety profile. The description does not mention edge cases like page out of range, but that is minor for this simple tool. Overall, it is complete enough for an agent to call it correctly.

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%, so all three parameters (page, search_context, account_link_id) have descriptions. The description reinforces that search_context comes from a prior search, which aligns with the schema. It does not add new meaning beyond the schema, so a baseline 3 is appropriate.

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 clearly states the tool fetches a page of KB Biz Card purchases from a prior search context, using the verb 'Fetch' with a specific resource. It distinguishes from init/search/result by implying it is for pagination, though it doesn't explicitly name sibling alternatives. The 'from a prior search context' clause helps differentiate it from a fresh search.

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 description explicitly requires a prior kb_biz_card__session__login call with the same account_link_id, which is a clear prerequisite. It also indicates the need for a prior search context, but it does not state when to use this tool versus alternatives like kb_biz_card__purchases__result or kb_biz_card__purchases__search. The usage context is implied but not fully enumerated.

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