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

The annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is clear. The description adds useful behavioral detail beyond annotations: it checks both apex and www, reports free/attached/erroring status, includes required DNS records, and reinforces that nothing is changed.

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 efficient sentence, front-loaded with the verb and resource, and ends with the important non-mutation guarantee. Every clause adds relevant 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 two-parameter read-only preflight tool with full schema coverage and rich annotations, the description provides enough context about what is checked and what kinds of results to expect. It does not explicitly explain how it relates to get_domain_status or set_domain, which keeps it short of fully complete routing guidance.

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 both parameters are already documented in the input schema. The description adds the useful detail that the candidate domain is checked at apex and www, but it does not explain the optional site id parameter, so baseline 3 is appropriate.

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 gives a specific verb and resource: preflight a candidate domain, covering apex + www and returning free/attached/erroring status plus required DNS records. It implicitly differentiates from sibling mutation tools by saying it changes nothing, but it does not explicitly name alternatives such as get_domain_status or set_domain.

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?

Usage is implied by the word "preflight": this is a read-only check to run before attaching or changing a domain. However, the description gives no explicit when-to-use guidance, no exclusions, and no named alternative for checking an already-attached domain.

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