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

Annotations already declare destructive=true, idempotent=true, readOnly=false, and the description adds real behavior on top: other domains 301-redirect to the chosen one, confirm=true applies while confirm=false is a dry run that reports the diff, and no charge is incurred. It does not describe reversibility or permission scope beyond the account token, so it is strong but not exhaustive.

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?

Three sentences, front-loaded with the prerequisite token requirement and the core action, with the confirm gate and cost note following. Dense and mostly waste-free, though the 'main name' clause and the search-engine/shared-link explanation are slightly redundant with each other.

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?

With no output schema, the description usefully covers the prerequisite, the dry-run/report behavior, and the redirect side effect, which is what an agent needs to call it safely. The remaining gap is the lack of any indication of failure modes (e.g., unknown domain or missing token) or how to verify the result afterward.

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 all three parameters (site, domain, confirm) are already documented with examples and semantics. The description restates the confirm semantics ('confirm=true applies it') without adding syntax or constraints beyond the schema, so the baseline of 3 applies.

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 verb and resource ('chooses which of a site's domains is its main name') and spells out the concrete effect (the domain that serves the site and is used by search engines and shared links). An agent can distinguish this from connect_domain, point_domain, or split_domain without opening a schema.

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?

Gives clear context for use: it needs an account token, it operates on a site that already has multiple domains, and it notes 'Does not charge.' It does not, however, name or exclude alternatives such as split_domain or connect_domain, so the routing guidance stops short of explicit when-not-to-use.

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