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

Goes well beyond the annotations: 850P per call, no charge on failure, up to 180s latency, PDF returned plus an X-Apick-Job-Id response header, and the dual idempotency semantics (idempotency_key prevents double payment; the download endpoint is unlimited at 30P). The annotations only say readOnly=false and idempotent=true; the description supplies the cost, timing, and failure-charge behavior an agent needs before spending points.

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 and cost are front-loaded and most sentences carry real information (timeout, failure refund, re-download). However, the pricing is stated twice — "건당 850P(PDF 전송 포함)" and the bracketed "[호출당 850포인트]" — which is redundant, and the mixed Korean/English makes scanning slower than necessary.

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 does the necessary work by stating that a PDF is returned and that the job id arrives in a response header. Cost, latency ceiling, refund-on-failure, and the re-download path cover the main risks of a paid, slow, external call. Minor gap: it doesn't say what a caller should do if the 180s window is exceeded or how partial/failed jobs surface.

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 description coverage is 100%, so all 8 parameters (pin, index, query, usage, record_scope, include_cancelled, publish_resident_no, idempotency_key) are already documented. The description only indirectly gestures at the target selector ("검색 결과의 대상을 지정하면") and adds nothing about the usage/record_scope enums or how index relates to query. Baseline 3 is correct when the schema carries the semantics.

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?

Opens with a specific verb+resource pair ("View and issue a real estate registry certificate") and makes the scope explicit with "in one call" — payment plus PDF retrieval completed in a single invocation. The phrase "검색 결과의 대상을 지정하면" ties it to the search sibling's output, so an agent can tell this apart from registry_realestate_search 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?

Clearly states the prerequisite context (pick a target from search results) and gives a concrete alternative path for re-retrieval: POST /rest/registry_jobs/:job_id/download at 30P rather than re-calling this tool. It stops short of an explicit "do not use this when…" or naming the sibling tools outright, so it lands at 4 rather than 5.

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