check_domain

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

Without annotations, the description carries full burden. It correctly states the tool checks availability, implying a read-only lookup. It does not detail side effects or response format, which is acceptable for a simple lookup, but could explicitly mention non-destructiveness.

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 a single concise sentence (11 words) that front-loads the purpose. Every word is necessary; no extraneous information.

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 tool with one parameter and no output schema, the description is adequate. It could mention output type (e.g., boolean) or suggest using check_domains_batch for multiple domains, but it is functionally complete.

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 100%, so baseline is 3. The tool description does not add extra meaning beyond what the schema already provides (e.g., format example). The parameter is sufficiently described in the schema.

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 tool's action (check), resource (domain name), and outcome (availability for registration). It distinguishes from siblings by specifying 'single', which contrasts with 'batch' in check_domains_batch and suggestion in suggest_domains.

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 implies usage for checking a single domain, but does not explicitly state when to use this over siblings like check_domains_batch for multiple domains or suggest_domains for alternative names. No exclusions or prerequisites are mentioned.

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