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

Annotations only provide readOnlyHint=false and destructiveHint=false, so the description carries much of the behavioral burden. It adds the key credential requirement and the sequencing requirement, but it does not disclose session effects, repeated-login behavior, or success/error outcomes.

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?

Two short sentences with no filler. The critical 'call first' instruction is front-loaded, followed by the provider and authentication method. Every sentence earns its place.

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 login tool with no output schema, the description provides the essential ordering and credential method, and the schema fully documents all five parameters. It omits post-login session behavior and verification steps, but those are not necessary for invoking the tool correctly.

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%, and each parameter already has detailed semantic documentation including conditional requirements (isoa_no for BE902) and defaults (BE904). The description adds no parameter-level meaning, so the baseline of 3 is appropriate.

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 names the specific verb ('Login'), resource ('work24 (고용24)'), and authentication mechanism ('공동인증서 / corporate joint certificate'). This clearly separates it from status-checking tools like work24__auth__session__status and from other providers' login tools.

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?

The opening instruction 'Call this FIRST before any other tool for this provider' is an explicit when-to-use directive with clear ordering context. It does not name alternatives or conditions for skipping login, such as checking an existing session first via work24__auth__session__status.

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