domain_add

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds the useful 'no purchase / virtual domain' context but does not disclose prerequisites (e.g., whether the domain must not already exist) or any auth/side-effect details.

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 one-line purpose followed by a compact Args block; every line earns its place with no redundancy. Appropriately sized for a two-parameter tool.

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?

An output schema exists, so return values needn't be explained, and annotations cover the safety profile. Still, a mutation tool benefits from stating preconditions or effects of registration, which are absent.

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 0%, so the description carries the burden, and it does well: hostname is illustrated with 'example.com' and zone_id is explained with a concrete default ('1 = .ru') plus a pointer to domain_zones for the full list. This compensates meaningfully for the empty 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?

States a specific verb ('register'/'зарегистрировать') and resource ('virtual domain'), and the parenthetical 'without purchase' scopes it away from a purchase flow. An agent can distinguish it from siblings like domain_delete, domain_list, or domain_check_to_register without opening the 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?

Usage is implied by the verb and the 'without purchase' qualifier, and it helpfully points to the domain_zones sibling for retrieving a zone_id. However, it gives no explicit when-to-use/when-not guidance and does not state alternatives for the registration action itself.

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