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

Goes well beyond the annotations: annotations only say readOnlyHint=false and destructiveHint=false, while the description discloses that nothing is charged, no carrier is contacted, the shipment can be deleted at any time, and an id is returned. For a write tool these are the exact side-effect facts an agent needs.

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?

Three tight sentences, front-loaded with the WRITE marker and the core scope, then the alternative, then the endpoint. Every sentence earns its place with no repetition of schema or annotation content.

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 9-parameter nested write tool with full schema coverage and no output schema, the description supplies the missing pieces: what is and isn't charged, reversibility, the return value ('shipment id'), and the sibling that buys a label. Nothing material is absent.

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 100%, so the schema already documents all 9 parameters (carrier, service, packages, addresses, etc.), making baseline 3 appropriate. The description adds no parameter-level detail beyond the conceptual 'create_shipping_label=false', which isn't even a field in the schema, so it does little extra work here.

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?

States a specific verb and resource ('save a shipment') plus a precise scope ('WITHOUT buying a label'), which distinguishes it cleanly from shipcloud_create_shipment_with_label. An agent can select it without opening either schema.

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?

Explicitly names the alternative and the condition that selects it: 'To buy the label use shipcloud_create_shipment_with_label.' That is exactly the routing decision an agent needs, with nothing left to inference.

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