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

Annotations already establish non-read-only, non-destructive, so the description mainly adds the per-call token cost ('호출마다 토큰 1소진') and the retry/idempotency contract. However, a large share of the text is generic boilerplate (e.g. 'anonymous taste calls', 'provider-specific idempotency_key') that adds noise rather than session-specific behavior, and there is no mention of session lifetime, auth prerequisites, or failure modes.

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 first sentence is well front-loaded with the critical ordering rule, but the middle of the description is bloated with generic idempotency boilerplate and an out-of-place Korean cost note. Several sentences could be trimmed without losing information relevant to this specific tool.

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?

For a session-establishment tool with no output schema, the description should say what a successful session yields and how long it lasts; that is missing. It does cover ordering and the token cost, which are the two behaviors an agent most needs here, so it is adequate but incomplete.

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 the baseline is 3; the description goes beyond by explaining exactly how request_idempotency_key should be generated and reused, which the schema itself defers to ('see the tool description'). account_link_id is left entirely to the schema, but the multi-connection guidance there is already sufficient.

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: 'Create an IBK fast-account session from the parent account link,' which is distinct from the sibling list/summary tools. The opening 'Call this FIRST before any other tool for this provider' also fixes its role in the tool chain.

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 an explicit ordering rule (call first, before any other tool for this provider) and explains the idempotency-key lifecycle: new key for new execution, reuse only to recover a lost response. It doesn't say whether a session must be refreshed, when a re-login is required, or what to do on failure, so it stops short of full when/when-not coverage.

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