List Proxy Locations

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds value beyond annotations by stating 'Public endpoint, no purchase required' and the pool_type limitation ('Not available for residential_premium'). These are behavioral traits not covered by annotations, so the description enriches the agent's understanding. No contradictions found.

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?

The description is two sentences, with the primary purpose front-loaded in the first sentence and usage context/constraints in the second. There is no wasted wording, and it efficiently conveys the essential information an agent needs. It is appropriately sized for the tool's complexity.

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?

The tool has no output schema, but the description explains what it returns conceptually (cities, states, ASNs, ZIP codes for a given pool type + country) and why it is used. It also mentions the availability constraint. Given the moderate complexity and the annotations covering read-only/idempotent behavior, the description is complete enough for correct invocation. A minor gap is the lack of an explicit note about the output format, but that is not critical.

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 100%, so all three parameters (kind, country, pool_type) are documented in the schema. The description does not add parameter-specific details beyond what the schema provides, but it does clarify the purpose of the output (discovering location_code values), which implicitly ties to the parameters. Since the schema covers semantics, baseline 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 states a specific verb ('List') and the resource ('available cities, states, ASNs, or ZIP codes') scoped by pool type and country. It explicitly distinguishes its purpose from siblings by noting it is for discovering valid location_code values before other tools like virtualsms_generate_proxy_endpoint and virtualsms_set_proxy_targeting. This is clear and 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?

The description gives explicit when-to-use guidance: 'Use this to discover valid location_code values before calling virtualsms_generate_proxy_endpoint or virtualsms_set_proxy_targeting with sub-country targeting.' It also states a key constraint ('Not available for residential_premium'), which helps the agent decide when not to use it. This is explicit and actionable.

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