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

Beyond the annotations (destructive, idempotent, non-readonly), the description discloses the account-token requirement, that autorenew=true is refused because it commits a charge, the confirm-gating, and 'Does not pay.' It adds real behavioral context the annotations cannot convey, though it does not detail error responses.

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 short sentences, front-loaded with the auth prerequisite, then read behavior, then the write/refusal rules. Every sentence carries distinct information with no padding.

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-capable tool with no output schema, it explains what is returned (renewal timing, price, auto-renew state), the auth need, and the confirm/refusal behavior. Only minor gaps remain around error handling and the effect of confirm on read-only calls.

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% (baseline 3), but the description adds the interaction semantics the schema only lists separately: autorenew=false only acts when confirm=true, autorenew=true is refused, and absent autorenew means read-only. This extra coupling meaning lifts it above baseline.

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 dual purpose: returning per-domain renewal dates, prices, and auto-renew status, plus optionally stopping renewal. The verb+resource is concrete, though it does not explicitly name which siblings (e.g. connect_domain, transfer_domain_out) it complements or replaces.

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 clearly conditions each mode: 'autorenew false with confirm=true stops the renewal,' 'autorenew true is refused,' and 'Absent means only read.' This tells the agent exactly which parameter combination to use for read vs. write, but no alternative tool is named.

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