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

The description adds meaningful behavioral details beyond the annotations: results are ordered busiest first, missing cities definitively mean not covered (closed-world semantics), and cities are always returned even when quiet so presence does not imply activity. These details are consistent with the readOnlyHint, idempotentHint, and openWorldHint=false annotations.

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 tightly written sentences, each carrying unique information: scope/ordering, coverage semantics, and the quiet-city caveat. The most important fact is front-loaded and there is no filler.

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 read-only list tool, the description plus schema and annotations cover selection criteria, ordering, coverage semantics, safety, and idempotency. No output schema exists, but the description sufficiently clarifies what the list represents and how to interpret it.

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?

The input schema already provides 100% parameter coverage with clear descriptions for limit, country, and activity. The tool description adds nothing about these parameters beyond the general ordering behavior, so the baseline score of 3 is appropriate.

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 uses a specific verb ('list') and resource ('every city Vicinity covers'), and adds a precise ordering rule ('busiest first'). It also frames the tool as the authoritative answer to coverage questions, which distinguishes it from siblings like get_coverage and get_city_status.

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 description clearly establishes when to use the tool: whenever the agent needs to answer 'is <place> covered?' It does not explicitly name alternatives or state when not to use it, but the authoritative framing gives strong contextual guidance among the sibling tools.

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