Get delivery label formats

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

With readOnlyHint=true already covering safety, the description adds rich behavioral context: the three mode values with their exact implications, the fact that formats is empty for NOT_SUPPORTED, the non-applicability of preselected when label_format is omitted, and the platform-specific ordering of returned services. These are exactly the behavioral quirks an agent needs to know.

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 compact and front-loaded with the core purpose, then adds only consequential details about modes, preselected behavior, and ordering. Every sentence earns its place and no information is repeated from the schema.

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 a single well-documented parameter, a read-only annotation, and no output schema, the description fully explains what the response contains (mode, formats, preselected), how to interpret it, and how to look up the correct service. An agent has everything necessary to call and consume the result correctly.

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%, and the schema already documents that delivery_service is an array, lists all allowed enum values, notes that duplicates are ignored, and provides the source path in get_order. The description itself adds little parameter-specific detail, but the schema carries that burden, so baseline 3 is appropriate.

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 starts with a specific verb and resource: 'List the label sizes the given delivery services can print.' It also distinguishes itself from get_order_delivery_labels by saying these are exactly the values accepted by that tool's label_format, so an agent can tell them apart immediately.

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 strongly implies when to use this tool: before generating labels, to learn valid label_format values for get_order_delivery_labels. It also gives important context about not applying preselected when label_format is omitted Mend and warns against relying on array position. It stops short of an explicit 'use this when...' statement or explicit alternative comparison, so it gets a 4 rather than 5.

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