compare_shipping_rates

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

With no annotations, the description carries full burden. It discloses the tool is free and requires no API key, but does not mention rate limits, precision of rates, or whether dimensions are needed for accurate comparisons. Behavioral traits are partially covered.

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?

Two sentences, no filler. The first sentence delivers the core purpose with carrier names, the second adds a key selling point (free, no API key). Highly efficient and front-loaded.

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?

No output schema is provided, so the description should hint at return format. It says 'returns cheapest and fastest options' but does not explain structure (e.g., object with carrier, price, time). Also does not clarify if dimensions are mandatory for accurate rates, though schema marks them optional.

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 baseline is 3. The description does not add extra meaning to parameters beyond what the schema provides; it only mentions carriers which are not reflected in parameters.

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 tool compares shipping rates across multiple named carriers (UPS, FedEx, USPS, DHL) and returns cheapest and fastest options. This distinctly separates it from sibling tools like track_shipment or list_shipments.

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?

No explicit guidance on when to use this tool versus alternatives among siblings, such as track_shipment for tracking or get_order_status for order details. The mention of 'Free — no API key needed' is a condition but not a comparative guideline.

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