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

Annotations are all false (readOnlyHint, destructiveHint, etc.), so the description carries the behavioral burden. It discloses that account creation is a write operation, that consent flags require genuine human confirmation, and that linking a checkoutToken attaches an existing order to the new account – a side effect beyond the schema. It doesn't cover error cases, but key behaviors are transparent.

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?

Four sentences, each carrying a distinct piece of information: purpose, credential sourcing, consent requirement with URLs, and conditional checkoutToken linking. The purpose is front-loaded in the first sentence, and there is no verbosity or repetition of schema details.

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 12-parameter, 7-required signup with a prior step and optional payment linking, the description covers the essential flow: verify code, collect real user data, require explicit consent, and link a previous checkout if present. It doesn't explicitly state that send_signup_code must be called first (though the schema's phone description pins this) or describe the return value, but these gaps are minor given annotations and schema coverage.

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 adds meaningful value by insisting that loginId/password/name be user-provided ('임의로 짓지 마세요') and by supplying the exact terms and privacy URLs to show the user, which the schema lacks. These are actionable semantics beyond the schema's descriptions.

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 opens with '[회원가입 2단계]' and states '인증번호를 확인하고 계정을 만듭니다' – a specific action (verify code and create account) with a clear resource (account). This clearly distinguishes it from sibling send_signup_code and other tools in the list.

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 conditional usage instructions: collect credentials directly from the user, only set consent flags after showing the linked terms and receiving explicit confirmation, and include checkoutToken only when a payment link was previously created. It doesn't explicitly name alternatives or when-not-to-use cases, but the step-2 label and schema reference to send_signup_code imply the sequencing.

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