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

Without the description the agent would have no idea this read-like call is metered. It discloses the billing model (first result 60P × (1 + 0.5 × (years-1)), free re-queries within the validity period), the async approval states, and the expiry behavior (RESULT_EXPIRED forces re-authentication). This adds substantial value beyond the annotations, which only cover the generic safety/idempotency hints.

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?

Purpose is front-loaded in the first clause, followed by state handling, billing, and result location. The bracket at the end compactly restates the cost rule. It is dense but every sentence carries actionable information; mildly packed rather than wasteful.

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?

With no output schema, the description carries the return-value burden and does so: it names resultAvailable, status, errorCode, result.npsDeductionCert, and resultExpiresAt, and explains the expiry error. For a polling-plus-billing tool this covers everything an agent needs to call and interpret 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?

There is only one parameter and schema description coverage is 100%, so the schema already documents the transactionId format (32 lowercase hex chars) and its source. The description restates the same origin (req_nps_deduction_cert) without adding format or usage detail, so the baseline of 3 applies.

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?

States a specific verb (조회/retrieve) and a precise resource (국민연금 소득공제용 납부확인서 결과), and explicitly ties itself to the sibling it depends on, req_nps_deduction_cert, whose transactionId it consumes. An agent can distinguish this from the request-side sibling without opening either schema.

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?

Gives concrete when-to-use guidance tied to the req_nps_deduction_cert call that produces the transactionId, and tells the agent how to act in each state: wait on AUTH_WAITING, re-query the same ID on COLLECTING, and resubmit a new auth after RESULT_EXPIRED. It does not frame the paired request tool as an explicit alternative or spell out a when-not-to-use case, 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.