webmaster_list_regions

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the trailing 'Read-only' adds nothing. The one genuinely useful behavioral fact — that these IDs feed webmaster_query_analytics — is disclosed, but nothing is said about pagination or result size despite a limit parameter.

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 terse statements front-load the resource and the downstream usage before the trailing qualifier. The final 'Read-only' fragment is wasted space because annotations already encode it, but overall nothing else is padded.

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 need no explanation, and annotations cover the safety profile. However, for a tool whose only required input (host_id) is undocumented and whose limit default of 100 raises unaddressed paging questions, the definition is only minimally complete.

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 must carry the burden, and it only gestures at filter_text ('filter by name'). The required host_id and the limit parameter are left completely unexplained, leaving an agent to infer what host context and pagination behavior are expected.

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 the resource (region directory) and its functional role — supplying region IDs consumed by webmaster_query_analytics — so an agent can tell it apart from other list tools like yandex_wordstat_regions. The verb is nominalized ('directory') rather than an explicit 'list', but the intent 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?

It states the purpose context clearly: use this to obtain region IDs for the region_ids parameter of webmaster_query_analytics, and it notes name-based filtering. It stops short of explicit when-not guidance or naming an alternative region source, so it is clear but not fully routing.

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