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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false. The description adds meaningful behavioral context beyond those annotations, including the cost of 10 credits, the boolean return fields, the verification date, and paid-tier differences for Tor detection and risk levels.

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 compact and front-loads the core purpose before return details and cost. It has minor redundancy in 'VPN Proxy Detector: VPN Proxy Detector checks...' but otherwise every sentence carries useful information.

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 simple one-parameter lookup with an output schema and annotations, the definition covers purpose, cost, return flags, and tier differences well enough to invoke it correctly. Its main gap is the lack of sibling differentiation for usage decisions, not missing behavioral or output context.

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% for the single required ip parameter, and the schema itself includes an example and description. The description only restates that any IP address can be checked, adding no format, IPv4/IPv6, or validation detail beyond the schema.

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 and resource: it checks an IP address to detect VPN connections and cloud datacenter hosting. It is clearly distinguishable from generic lookup siblings by naming VPN and datacenter detection, though it does not explicitly contrast against related tools such as IPLookup or TorNodeDetector.

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 explains what the tool checks but gives no explicit when-to-use guidance, exclusions, or routing to alternatives. With sibling tools like IPLookup, TorNodeDetector, and BotDetector available, the agent receives no help deciding when this VPN-specific detector is the right choice.

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