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

With no annotations present, the description carries the full burden and handles it well. It explicitly discloses a financial side effect ('Deducts from account balance'), clarifies that this is a staged action rather than immediate execution, and specifies that executeConfirmedAction must be called after user approval. This is materially important behavioral information.

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 compact and front-loaded: purpose first, then key requirements, then the return value and required follow-up. Every sentence earns its place, and there is no redundant filler.

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 two-step mutation flow with no output schema, the description explains what the tool returns (actionId), what to do with it, and the key consequence (deducting balance). The agent has enough context to call the tool and complete the confirmation flow correctly.

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 description coverage is only 33%, with domain and years lacking schema descriptions. The description compensates by providing a domain format example ('example.com') and the allowed years range (1-10). The sessionKey parameter is documented in the schema, so coverage across parameters is adequate.

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 the operation: 'Stage renewal of a domain for a specified number of years.' It names the resource (domain), the action (renewal), and the key constraint (years). This differentiates it from sibling tools like registerDomain, transferDomain, and updateDomainAutoRenew.

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 gives concrete usage context: required inputs, valid years range, and the confirm-then-execute flow via executeConfirmedAction. It does not explicitly name alternatives or exclusions, but the domain renewal context is clear enough for an agent to use it appropriately.

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