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

Adds real context beyond the annotations: it authenticates via NPKI certificate, returns an API_KEY used to chain later calls, and costs one token per invocation ('호출마다 토큰 1소진'). The idempotency paragraph is dense and slightly muddled (login itself is unauthenticated, yet the key is described as 'for an authenticated call'), and the 'anonymous taste calls' phrase is unexplained boilerplate.

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?

Front-loaded well with the critical ordering instruction, but the middle is a long generic idempotency boilerplate block that reads as injected template text, and the trailing Korean token-cost note is a language switch tacked on at the end.

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?

No output schema, and the description compensates by stating the return value (API_KEY for chaining) plus cost and idempotency behavior. Missing only operational edge cases: what happens on certificate failure or expired session, and whether re-login is safe once a session exists.

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% and the schema itself defers the request_idempotency_key definition to this description, so the description genuinely carries that parameter's meaning (generate before first request, reuse only for lost-response recovery). account_link_id is never mentioned in the description, but the schema already documents it fully.

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 ('Login to NHIS EDI via NPKI certificate') and names its distinctive output ('Returns API_KEY for chaining'), which separates it from read-only siblings like nhis_edi__session__status. The 'Call this FIRST before any other tool for this provider' opener pins down its role immediately.

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?

Explicit sequencing guidance ('FIRST before any other tool') and explicit idempotency-key lifecycle rules (reuse only to recover a lost response, new key for new execution). It does not mention alternatives such as nhis_edi__session__status or what to do if a session is already active, so the routing advice is one-sided.

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