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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered; the description adds the auth prerequisite and a per-call token cost note, which is useful. However, roughly half the text is a dense idempotency-key policy for one optional parameter, and it says nothing about what a "payment row" contains or how pagination/max_pages behaves.

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 prerequisite is correctly front-loaded, and the closing token-cost note is valuable. The middle is disproportionately devoted to idempotency edge cases (recovery-after-lost-response, anonymous taste calls, provider-specific key collisions) while core search behavior goes unmentioned, so the word budget is misallocated.

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?

There is no output schema, and the tool sits in a multi-step init/page/result family, yet the description never explains that flow or what a search returns. Combined with the silent pagination parameters, an agent can call it but cannot predict the result set or know whether it must follow up with payments__result.

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 baseline is 3, but the description earns above baseline because the schema's request_idempotency_key entry explicitly defers to it ("see the tool description") and the description supplies the full reuse-vs-new-key semantics, plus ties account_link_id to the login requirement. It still does not clarify date format expectations, page, or max_pages beyond what the schema already states.

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 a specific verb and resource: "Search KB Biz Card payments rows," which is clear and unambiguous. It never differentiates itself from the closely related siblings kb_biz_card__payments__init/__page/__result or from purchases__search and approvals__search, so an agent must infer which of the payments tools to call.

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 a hard prerequisite (a prior kb_biz_card__session__login with the same account_link_id), which is genuine usage guidance. It never says when to choose this over payments__page, payments__result, or purchases__search, so the sibling-selection question is left unanswered.

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