Add site to Webmaster

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

Annotations already disclose readOnlyHint=false, openWorldHint=true, idempotentHint=false, and destructiveHint=false. The description adds genuinely new context: the host requires verification after creation, and that delete-host is irreversible and needs confirmation. It does not describe return values, but those are less critical here.

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?

Four tight sentences, front-loaded with the action, then the protocol requirement, then sibling routing. Every sentence carries distinct information with no repetition.

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 one-parameter mutation tool with full schema coverage and annotations covering the safety profile, the description covers trigger, format constraint, post-condition (verification), and alternatives. Nothing an agent needs to call it 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% and the single parameter's description matches the schema text verbatim ('Site URL with protocol'). The description adds no syntax or format detail beyond what the schema already states, so the baseline 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 ('Add a new site (host) to Yandex Webmaster') and immediately disambiguates from siblings by naming verify-host, start-verification, and delete-host. An agent can distinguish this from the many get-* siblings 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?

Provides explicit trigger ('Use when the user asks to add a new site') plus two negative routings: ownership checks go to verify-host/start-verification, and removal goes to delete-host. This is the full when/when-not/alternatives pattern.

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