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

Annotations already declare readOnly, non-destructive, closed-world behavior, so the safety profile is covered. The description adds genuinely useful context beyond them: result ordering by place count, that bounding boxes are only present 'when known', and that each area carries a place count. It does not discuss pagination or the response envelope, but with an output schema present that is acceptable.

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 with the core purpose, then layers scope, fields and filtering in one dense paragraph with little waste. The middle clause about geographic coverage is slightly long but still earns its place by telling the agent what data exists.

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 zero-required-parameter listing tool with an output schema and full annotations, the description supplies the needed context: what areas are, what fields they carry, how to filter, and how results are ordered. Only the undocumented `limit` parameter and pagination behavior remain uncovered.

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 67%, with `q` and `level` documented in the schema and `limit` undocumented in both places. The description restates `q` as a substring of the name and `level` as the level filter, adding only marginal detail beyond the schema's own wording, 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 ('List supported areas') and immediately scopes it: cities, neighborhoods and states, with geographic coverage named. An agent can distinguish this catalog-listing tool from search_places 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?

Gives clear operational context — filter with `q` and `level`, results ordered by place count — and connects this tool to a downstream one ('an `id` you can pass to search'). It never states when to prefer this over a sibling like list_categories or search_places, so it stops short of a 5.

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