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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior. The description adds meaningful context beyond that: it returns a link only, does not fetch live status or location, and explains carrier booking constraints including the UPS situation in Ukraine. It does not describe the exact return shape, but that gap is minor for a link-returning tool.

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 action and return value, then adds exclusion and carrier context. Every sentence contributes useful information, though the carrier caveat is somewhat dense and includes a parenthetical operational note. It remains efficient overall.

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?

With only two required parameters, full schema coverage, and annotations covering safety and idempotency, the description supplies everything else an agent needs: what is returned, what is not fetched, and how carrier options work. No output schema exists, but the description already states that the return value is a tracking page link.

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 both parameters are already documented by the schema itself. The description still adds real meaning for the 'carrier' parameter by explaining that SEMERO books DHL and FedEx while UPS and GLS links apply only to existing customer waybills. It adds no extra detail for 'awb' beyond the schema, so it falls short of a full 5.

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 and resource: 'Returns the carrier's official tracking page link for a waybill number (AWB, накладна, трек-номер).' It also explicitly excludes adjacent capabilities ('Does not fetch status or location'), which prevents confusion with a shipment-status tool. No sibling tool is similar, so the purpose stands alone clearly.

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?

It gives an explicit trigger ('Use when the user wants to track a shipment') and an explicit non-use case ('Does not fetch status or location; shipment statuses are emailed automatically'). The carrier-specific constraints further guide when the tool is appropriate for UPS/GLS versus DHL/FedEx waybills.

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