zia_url_lookup

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

The annotations already declare 'readOnlyHint: true', indicating a safe read operation. The description adds that the tool works on a list of URLs/domains, but does not disclose any additional behavioral traits (e.g., rate limits, authentication requirements, or response structure). With annotations covering the read-only nature, the description contributes minimal extra transparency.

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 a single, clear sentence of only 10 words. It contains no unnecessary information and is front-loaded with the main action and resource.

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 tool with 2 parameters and no output schema, the description adequately explains the purpose. However, it lacks information about return values, limits on the number of URLs, or error conditions. The missing output schema means the agent has no insight into the response format, which is a significant 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?

The schema description coverage is 50% (only 'query' has a description). The tool description mentions 'a list of URLs/domains', which provides context for the 'urls' parameter but does not specify format or constraints. The 'query' parameter is well-documented in the schema. The description partially compensates for the missing 'urls' parameter description but could be more explicit.

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 the action ('look up') and the resource ('URL category classifications'). It is specific and distinguishes this tool from sibling tools like 'zia_list_url_categories' (which lists categories) and 'zia_get_url_category' (which retrieves a single category). The tool is clearly for classifying URLs, not managing categories.

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 no guidance on when to use this tool versus alternatives, such as when a particular URL classification is needed or if there are limits on the number of URLs. No context about prerequisites or exclusions is given.

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