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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds meaningful context beyond annotations by stating that the tool does not contact the business and by providing cost (free, no key) and latency (~500ms), which helps an agent decide to invoke 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?

The description is front-loaded with the core behavior and then uses labeled sections (example, when to use, when not to use, cost, latency). Every section adds decision-relevant information with no filler or repetition.

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?

Despite having no output schema, the description states what the lookup returns (contact channels, capabilities, last verified), when to call it, when not to call it, cost, and latency. This is sufficient for an agent to select and invoke the tool 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?

Schema coverage is 0%, but the description compensates with a worked example mapping smb_id and capability_to_verify to concrete values, and the 'WHEN TO USE' text explains capability_to_verify as a confirmed-capability check. It doesn't explicitly define the exact smb_id format or the optionality behavior, but the example and context make parameter usage clear enough.

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 opens with a specific action and resource ('Look up what we know about a business in our supply network') and lists the returned data (contact channels, capabilities, last verified). It adds a sharp disambiguation ('DIRECTORY LOOKUP - it does not contact the business') that separates it from call_business, but it does not explicitly differentiate from the similarly named sibling verify_company_record.

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 'WHEN TO USE' and 'WHEN NOT TO USE' sections give explicit conditions with a concrete example: use before communications/scheduling for unverified identifiers or confirmed capability, and avoid when find_business returned the SMB within 24 hours because it is already verified. It names the alternative tool find_business, leaving little to inference.

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