urlhausLookup

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

With no annotations, the description carries the full burden. 'Look up' implies a read-only query and naming URLhaus gives the data source, but it does not mention response format, error behavior, rate limits, or access requirements. It barely meets the minimum transparency bar.

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?

A single, front-loaded sentence conveys the purpose and usage with no wasted words. Every phrase contributes meaningful 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?

The tool is simple and the description covers purpose and parameter selection, but with no output schema it should also indicate what kind of result is returned (e.g., reputation data, tags, timestamps). This missing return-value context leaves the description minimally viable but incomplete.

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 coverage is 100%, so the schema already documents both parameters. The description adds the valuable mutual-exclusion rule ('either... or...') and clarifies the expected format, going beyond the schema's individual descriptions.

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 ('Look up') and names the exact resource ('URLhaus (abuse.ch)'). It clearly distinguishes this from sibling tools like urlhausTag by specifying both URL and host lookups.

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 provides parameter-level guidance ('Provide either a full URL... or a hostname/IP...') but does not explain when to prefer this tool over alternatives like urlhausTag or other threat-intel lookups. There are no exclusions or alternative tool references.

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