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

Annotations already declare readOnly, idempotent, non-destructive. The description adds the meaning of the risk score (not a probability of attack), the evidence components, and rate-limit behavior, which are not captured in annotations. This goes beyond the structured data without contradicting it.

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 sentences, with the core purpose and return summary in the first, a crucial clarification in the second, and operational details (rate limits, auth) in the third. No wasted words, and the most important information is front-loaded.

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?

With no output schema, the description compensates by listing all return components (risk score, evidence state, network, geographic attribution) and explains the score's interpretation. One parameter is fully covered. The tool's complexity is low, and the description is sufficient for an agent to call it correctly.

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 sole parameter 'ip' is fully described in the schema (coverage 100%), including example formats. The description reiterates IPv4/IPv6 but adds no new semantics beyond the schema. 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 clearly states a specific verb ('look up') and resource ('IPv4 or IPv6 address'), and enumerates the returned information (risk score, evidence state, network, geography). With no siblings, it stands alone as a clear purpose.

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?

Although there are no sibling tools, the description provides usage context by specifying rate limits (1000/day, 60/min) and the option for higher limits via API key. It doesn't explicitly state when to use it, but the purpose makes that obvious. No exclusions are needed given no alternatives.

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