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

No annotations exist, so the description carries the full load — and it does disclose the important behavior: what gets sent to the user per method, that the user must open a URL and approve, that approval is polled via check_signup, and that terms consent and identity verification are performed by the user, not the agent. It stops short of stating return payload shape or any auth/rate constraints, 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?

Front-loaded with purpose and the hard precondition, then cleanly branched by method with no filler sentences. It is longer than strictly minimal, but every clause carries operational meaning; only the closing consent sentence partially overlaps with the precondition.

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 mutation entry-point with no annotations and no output schema, the description covers the trigger condition, both branches, what the user sees, and where to go next. What an agent receives back (e.g., a status or handle) is only implied by the branch narratives rather than stated.

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 schema leaves the method enum undocumented, but the description supplies the meaning of both enum values and their distinct flows, which is exactly the gap-filling needed. email and client_name semantics live in the schema (67% coverage); client_name in particular is never echoed in the description, so the description does not fully compensate for the missing third.

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 ('ChatAd 가입을 시작한다') and immediately splits it into its two concrete modes (email_code, device), each with distinct downstream behavior. Naming complete_signup and check_signup as the follow-on tools makes it unambiguously distinct from those siblings.

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, emphasized precondition ('🔴 사용자가 가입하겠다고 답한 뒤에만 부른다') and then routes per-method: email_code goes to complete_signup, device goes to check_signup. The agent knows both when to call it and which sibling to hand off to in each branch.

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