Delivery: cancel parcel [sandbox]

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

Annotations already indicate destructiveHint=true and readOnlyHint=false. The description adds valuable context: it cancels on behalf of the receiver, is sandbox-only, and only works for specific parcels. It also notes access restrictions (delivery-service PARTNERS). No contradictions with annotations.

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 a concise three-sentence paragraph with no fluff. It states purpose, constraints, and differentiation in a logical order. Could be slightly more structured with bullet points, but it is 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?

Given the tool has 4 parameters including a nested object (parcelID) and no output schema, the description provides basic completeness: purpose, constraints, return status. However, it does not explain the structure of parcelID (an object with propertyNames), nor provide usage examples or details on the success response. Schema descriptions for parcelID and actor are minimal, and the description does not compensate fully.

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 mentions the actor field is for receiver, but this is already in the schema. It adds the constraint that only parcels from delivery_create_sandbox_parcel_v2 are valid, linking to a sibling. However, the description does not explain the complex parcelID object structure beyond what the schema says.

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 it cancels a test parcel on behalf of the receiver and returns a success status. It specifies that only parcels created via delivery_create_sandbox_parcel_v2 can be cancelled, and distinguishes itself from delivery_v1_cancel_parcel by mentioning the actor field and being the base contract.

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 clear context: it is for sandbox/test parcels, only for parcels created via a specific v2 method, and for delivery-service PARTNERS only. It contrasts with delivery_v1_cancel_parcel, giving agents guidance on when to use each. However, it does not exhaustively list all alternatives or conditions not to use.

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