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

Annotations already declare destructiveHint=true, so the write/create nature is covered; the description adds substantial extra context — the list_domains dependency, active-status requirement, partition-matching constraint, and the apex/subdomain capability rules. It doesn't describe rollback or quota behavior, keeping it just short of a 5.

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-loads the purpose and the deploy follow-up path before the parameter rules. Dense and mostly earned, though the apex/subdomain paragraph is lengthy and partly duplicates schema guidance.

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 mutation tool with no output schema, it names the return values, the prerequisite lookup tool, the confirmation flow location, and the capability constraints. An agent has everything needed to call it correctly without opening the schema.

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 the baseline is 3, but the description adds real cross-parameter semantics beyond the schema: domain must come from list_domains, partition must match domain, and subdomain validity depends on the domain's enableApexDomain/enableSubdomains capabilities. The www/apex rule overlaps with the schema text, so not a full 5.

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+resource ('Create a new Hostsmith site') and names the return payload (siteId, URL, configuration). It clearly routes the agent away from sibling deploy tools and delete_site, so selection is unambiguous.

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?

Explicitly states when to use it ('publish or host new content and no suitable site already exists') and names the correct follow-up alternatives, deploy_files vs deploy_create_upload + deploy_finalize, with the condition (inline text vs binaries > ~1 MB) that selects between them.

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