mailkite_register_domain

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

Beyond the annotations (readOnlyHint false, idempotentHint false, destructiveHint false), the description adds crucial behavioral details: it charges the registrar, requires a management session token, does not register automatically but returns a dashboard link for user review, and explicitly states an assistant cannot purchase alone. This fully discloses side effects and auth requirements.

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 sentences, front-loaded with the primary action and side effects, then the crucial limitation. Every sentence carries useful information with no filler. The structure is efficient and easy to parse.

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?

Given the tool's complexity (4 params, nested object, financial consequences) and absence of an output schema, the description covers key aspects: the outcome (returns a dashboard link), auth requirement, and the non-automatic nature. However, it omits explanation of the dryRun parameter (which would be very useful) and does not mention the contact object's purpose beyond the schema. Still, an agent can determine when to call it and roughly what to expect.

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 has 4 parameters with 0% description coverage overall (only nested fields like phone have descriptions). The description does not explain the meaning of 'years' or the purpose of 'dryRun', which is critical for a domain purchase (to test without charging). It also does not describe the required 'contact' object structure beyond what the schema already shows.

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 states a specific verb and resource: 'Register (buy) a domain on the customer's behalf'. It clearly distinguishes this from sibling tools like check_domain_availability or create_domain by emphasizing the purchase and provisioning in one call. The scope is unambiguous.

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?

It provides clear context on when to use: it requires a management session token and explicitly warns that an assistant can never purchase a domain on its own, indicating it is not for finalizing the purchase without user confirmation. However, it does not name alternatives like check_domain_availability for pre-checking, leaving some inference to the agent.

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