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

Discloses billing behavior (charged on first result return, free re-queries within validity), the expiry behavior (RESULT_EXPIRED after resultExpiresAt), the polling states, and where the payload lives (result.personalIncome). It also notes re-auth is required after expiry. This goes well beyond the annotations. The readOnlyHint=false vs. a pure read query is slightly at odds but explainable by billing side effects, so no contradiction.

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?

Four dense Korean sentences, front-loaded with the core action, then state handling, then billing, then result location. The bracketed repetition of the billing rule is redundant with the earlier sentence but otherwise contains no filler.

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?

Covers everything an agent needs for a single-param polling/result tool: the producing sibling, the polling states and re-query cadence, the billing trigger, the expiry failure mode, and the result field location. No output schema exists, yet the description still points to the key result fields (resultAvailable, status, errorCode, result.personalIncome).

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; the description adds real value by tying transactionId's provenance to req_personal_income's response and by clarifying that the same ID can be reused within the validity window, which the schema does not state.

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?

Specifies a clear verb (조회) and resource (금융소득 조회 결과), and explicitly distinguishes itself from its sibling req_personal_income by positioning itself as the result-retrieval tool that consumes the transactionId produced by req_personal_income. An agent can tell the pair apart without inspecting schemas.

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 explicit when-to-use routing: on AUTH_WAITING wait for mobile approval; on COLLECTING re-query later with the same ID; on RESULT_EXPIRED submit a new authentication (req_personal_income). This is a full state-machine guide, not just a hint.

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