list_locations

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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true, destructiveHint=false), so the bar is lower, and the description adds genuinely useful behavior: the 100-row cap and the next_offset/offset continuation loop. It does not mention auth, rate limits, or errors beyond pagination.

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 short sentences, front-loaded with the purpose before the parameter rules and pagination mechanics. Nearly every clause earns its place, though the pagination sentence is slightly terse relative to its importance.

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 needn't be explained, and the description still helpfully notes next_offset. For a 6-parameter tool it is largely complete, but the omission of limit and connection_type leaves a small gap.

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 load. It explains the meaning of country_code and region_code per kind and the offset continuation, but never mentions limit or connection_type (an enum with residential/mobile), leaving two parameters undocumented.

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 ('List locations available for targeting') and immediately frames the purpose: producing the codes that proxy_url consumes. This explicitly ties it to the sibling proxy_url and distinguishes it from unrelated siblings like traffic_stats or top_domains.

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 hierarchy-aware guidance: 'regions need country_code; cities and isps can be narrowed by country_code and region_code.' This tells the agent which parameters matter for which kind. It stops short of naming alternative tools or stating when not to call it, so it lands at 4 rather than 5.

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