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

Beyond the readOnlyHint/non-destructive annotations, it discloses an auth prerequisite tied to a specific account_link_id and a per-call cost ('호출마다 토큰 1소진'), which materially affects invocation strategy. It also spells out idempotency-key semantics (generate before first call, reuse only to recover a lost response, new key for new execution), though it omits what the detail payload contains.

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 and purpose are correctly front-loaded, but the middle block spends four sentences on idempotency for a read-only lookup, including the awkward 'anonymous taste calls' phrasing and an aside about provider-specific keys. It is informative but over-weighted relative to a single-invoice fetch.

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?

Auth, identifier provenance, and cost are covered, but with no output schema and no statement of what 'detailed information' contains (line items, parties, tax amounts), an agent cannot anticipate the response shape. For a detail tool this is a noticeable gap.

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 already 100%, so the baseline would be 3; the description earns above that by being the authoritative explanation of the idempotency key lifecycle and by reiterating where etan comes from and that account_link_id must match the login call. The schema's idempotency field literally defers to the tool description, so this text is doing real work.

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 and resource: 'Get detailed information for a specific e-tax invoice by its 승인번호 (etan)'. The identifier-based retrieval clearly separates it from the sibling list/summary/statistics invoice tools without needing to open any 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 the prerequisite ('REQUIRES prior hometax__session__login call with same account_link_id') and the exact upstream source for its required argument ('Get etan from hometax__etax__invoice__search_list results'). It does not explicitly state when not to use it versus search_summary/search_statistics, but the context is clear.

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