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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description discloses that the tool does not contact the business, which is a meaningful behavioral trait. It also outlines what data is returned and includes cost and latency context, all consistent with the annotations.

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 well structured and front-loaded: purpose first, then the key non-contact caveat, a relevant example, and clear WHEN TO USE/WHEN NOT TO USE sections. Every section serves a purpose, with no redundant filler.

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 lookup tool with no output schema, the description explains what the tool returns, when to use it, when not to use it, and provides a full example invocation. It lacks an explicit statement that capability_to_verify is optional and does not describe failure behavior, but these are minor gaps given the annotations and the example.

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 0%, so the description must compensate. It partially does via a concrete example mapping a user query to smb_id and capability_to_verify, and the opening sentence references capabilities. However, it does not define valid values for capability_to_verify, clarify the format of smb_id, or note that capability_to_verify is optional.

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 ('look up') and resource ('a business in our supply network'), then enumerates what the lookup returns: contact channels, capabilities, and last verification time. It explicitly labels itself a 'DIRECTORY LOOKUP' and contrasts with contacting the business, and the WHEN NOT TO USE section distinguishes it from find_business.

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 explicit WHEN TO USE and WHEN NOT TO USE rules, including a concrete alternative tool (find_business) and a temporal condition (results within the last 24 hours are already verified). This gives an agent clear decision criteria for selecting this tool over siblings.

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