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

Adds meaningful traits beyond the readOnly/idempotent/openWorld annotations: cost ('FREE (no credits)') and a subtle failure mode — interpreting an empty `hosts` list incorrectly unless `requiresReconnect` is checked. That turns a silent trap into actionable guidance.

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 tight clauses ordered purpose → usage → edge case. No filler, and the most actionable warning (requiresReconnect) lands where an agent will read it before acting.

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?

No output schema exists, so the description carries the return-value burden and does so by naming both `hosts` and `requiresReconnect`. Combined with the annotation-covered safety profile, an agent has everything needed to call it correctly.

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 (projectId) is fully documented in the schema, including where to obtain it. The description adds nothing about the parameter, 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+resource ('every host the caller's connected Yandex Webmaster OAuth grant can access') and immediately frames its role relative to a sibling (see set_yandex_host). An agent can distinguish it from get_yandex_site_overview, list_bing_sites, and other list_* tools without opening any 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?

Clearly signals the when: it is 'the data source for picking which host to bind to a project', pointing at set_yandex_host as the downstream consumer. It gives strong positive context but no explicit exclusion (e.g., when to reach for a different Yandex tool instead).

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