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

Annotations already disclose readOnly=false, destructive=false, idempotent=true, and openWorld=true, so the safety profile is covered. The description adds genuinely non-derivable behavior: hostId is re-validated against the caller's LIVE host list on every call, which tells the agent a stale or fabricated hostId will fail at invocation time.

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?

Two sentences, zero padding, with the action front-loaded and the validation caveat immediately after it. Every clause carries information an agent needs.

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 two-parameter mutation tool with a full annotation set and no output schema, the description covers what it does, the upsert/repoint semantics, and the key failure mode (stale hostId). It does not say what is returned or what happens to a previously bound host, but those are minor gaps given the annotation coverage.

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% (both parameters carry descriptions and the hostId format is spelled out), so the baseline is 3. The description goes beyond the schema by stating the live re-validation of hostId on every call, adding operational meaning about when that value can be trusted.

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?

The description names a specific verb pair ('Link (or repoint)') and a specific resource ('a project's Yandex Webmaster host'), making it clearly distinct from siblings like list_yandex_hosts, disconnect_yandex, or reindex_yandex_url. It stops short of explicitly naming which sibling to use instead, so it is clear but not fully sibling-differentiated.

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?

The 'link (or repoint)' framing implies the context of use (binding a host to a project, including overwriting an existing binding), but there is no explicit when-to-use statement, no when-not-to-use exclusion, and no named alternative. The only routing hint, that hostId comes from list_yandex_hosts, lives in the schema rather than the description.

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