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

With no annotations, the description carries the burden and it discloses a key side effect (sending an email to the registrant) and the fact that the code is not returned but must be obtained from the user. It adds behavioral context beyond the schema and name, though it omits details like error conditions or idempotency.

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 tight and well-structured: a one-sentence purpose, a clear bullet-like flow, and a concise args section. Every sentence adds value with no redundancy.

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 simple one-param tool with no annotations, the description adequately explains the tool's role in the broader flow and the required next steps. It doesn't explain the output, but an output schema exists, so that's acceptable. Some minor gaps like rate limits or re-sending behavior prevent a 5.

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 0% and the description compensates by explaining 'order_id: The order ID of a completed domain purchase.' This adds meaning beyond the schema's bare string type, making the parameter's purpose and prerequisite clear.

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 'Start the transfer verification flow by sending a code to the registrant's email' which is a specific verb+resource+action. It distinguishes from siblings by positioning itself as the initial step in a multi-step flow, explicitly naming the order of calls.

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?

Explicitly says 'Always call this before get_transfer_code or unlock_domain' and provides the subsequent steps: ask user for the code, then call verify_transfer_code. This gives clear when-to-use and ordering guidance relative to alternatives.

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