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

Goes well beyond the annotations (which only say non-read-only, non-destructive, open-world). It discloses the returned DNS record set, the critical gating rule that the site is not served until the TXT proof record is seen, and the enumerable statuses pending/verifying/active — exactly the operational context an agent needs before calling.

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?

Front-loaded with the trigger condition and kept to a single, information-dense sentence with no filler. It is slightly run-on due to stacked parentheticals, but every clause carries distinct 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?

Despite having an output schema, the description still conveys the return shape (DNS steps, status values, HTTPS reachability) and the verification dependency. Nothing needed to call this two-mode, 3-parameter tool correctly is missing.

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%, so baseline is 3, but the description adds real meaning: it explains the present-vs-absent semantics of `domain` as the mode switch and that `with_www` governs which address is primary and which redirects. That goes past the schema's field-level text.

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?

States a specific action pair on a specific resource: connecting the user's own domain to a site, or checking its current status. The dual-mode framing (with vs. without `domain`) leaves no ambiguity about what the tool does, and the example domain makes the outcome concrete.

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?

Opens with an explicit trigger: 'Use when the user wants their own domain ... on a site, or asks whether it works yet', and maps each mode to its invocation condition (supply `domain` to connect, omit it to check). No alternative tools are named or excluded, so it stops just short of a 5.

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