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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, but the description adds crucial behavioral context beyond those: it does not contact the business, it is a directory lookup, it costs nothing, and typical latency is ~500ms. This is exactly the kind of non-obvious behavior an agent needs to know before invoking.

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 organized into clear labeled sections and front-loads the core behavior. The example query, usage guidance, cost, and latency each earn their place and no section is redundant. The formatting makes it easy for an agent to parse quickly.

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 covers what the tool returns, when to use it, when not to use it, cost, latency, and the critical 'does not contact the business' caveat. An agent has enough context to select and correctly invoke the tool with the right parameters.

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 carries the burden. It adds meaning to both parameters: smb_id is an 'SMB identifier' and capability_to_verify is demonstrated in the example query ('emergency_plumbing') and in WHEN TO USE ('confirmed capability'). It does not fully specify allowed capability values or behavior when omitted, but the example and context provide strong compensation.

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') and lists the exact data returned: contact channels, capabilities, and last verification time. It explicitly distinguishes itself as a DIRECTORY LOOKUP that does not contact the business, which separates it from sibling tools like call_business and 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 description provides explicit WHEN TO USE and WHEN NOT TO USE sections, plus a concrete user query example. It names find_business as the sibling alternative and gives a clear condition ('returned from find_business within the last 24 hours') under which this tool should not be used.

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