login_status

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

Annotations only declare readOnlyHint=true; the description goes further by disclosing what is NOT returned ('Keys and cookies are never returned') and what the call yields (authenticated, message), which matters for a credential-adjacent tool. It stops short of describing caching or expiry semantics, so not a 5.

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?

Content is front-loaded: purpose first, then return shape, then the routing hint. The Korean/English duplication adds length but each language block carries the same compact payload and no sentence is 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?

For a zero-parameter read tool with an output schema already covering the return fields and annotations covering the safety profile, the description supplies the two things an agent actually needs: what validity means here and which sibling to call when the session is dead.

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?

The tool takes zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate.

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?

The description states a specific verb and resource ('저장된 포털 세션의 유효성을 확인합니다' / check whether the saved portal login is valid), which is clearly separable from the sibling 'login' and the other data tools in the set.

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?

It explicitly names the alternative tool and the condition that selects it: '세션이 없거나 만료되면 login 도구로 로그인하세요 / Use login for missing or expired sessions.' Clear routing, though it does not state the situations in which checking status (rather than going straight to login) is the right first step.

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