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

The annotation readOnlyHint: true already indicates it's a safe read operation. The description adds behavioral context such as the legal compliance requirement and the per-call cost of 40 points, plus parameter constraints. These go beyond the annotations and provide useful operational guidance, though the return format is not described.

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 description is moderately concise, with the redundant Korean sentence repeating the first English sentence being the main inefficiency. However, the rest of the sentences each add unique value (parameter details, legal note, cost), so it remains well-structured and informative.

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?

At 3 parameters with no output schema, the description provides enough context to understand the tool's purpose and constraints, but it does not describe the return value or error behavior. Given the tool is for verification, this omission leaves some ambiguity for the agent regarding how to interpret the result.

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 input schema has 100% description coverage for all 3 parameters. The description adds extra semantic detail, particularly the 11-digit format for card_sn and the conditional requirement that it becomes mandatory for cards issued after 2011-01-01, which is not in the schema.

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 clearly states it verifies the authenticity of a Korean alien registration card using text input, which is a specific verb and resource. It distinguishes from image-based siblings by explicitly mentioning 'text input'.

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 description provides context for when the tool should be used, including legal basis ('정보주체의 동의 등 적법한 처리 근거를 확보한 경우에만 사용하십시오') and conditional requirement for card_sn for cards issued after 2011-01-01. However, it does not explicitly name alternatives or state when not to use it.

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