create_label

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

With no annotations, the description discloses behavioral traits: input structure, override logic, optional output suppression, and return format. It mentions that config is for testing, implying normal credential loading from environment. It does not mention costs or destructive nature, but the behavior is well-explained.

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 well-structured: purpose first, then request details, then optional parameters and return value. It is somewhat verbose but every sentence adds value. Front-loading works well.

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 complexity (4 params, nested objects, output schema exists), the description covers input structure, overrides, credential handling, and return format. It does not detail all sub-fields but provides sufficient context for an agent to use the tool 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 0%, but the description fully compensates by detailing the nested request structure, address fields, carrier/product, parcels, references, label format, and the purpose of carrier, config, and include_label. This adds significant meaning beyond the bare schema.

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 'Create a shipping label from a canonical shipment request,' specifying the verb, resource, and primary action. It distinguishes itself from siblings (describe_carrier, list_carriers) which are about carrier info, not label creation.

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 explains when to use optional parameters like 'carrier' (overrides request value) and 'config' (for ad-hoc testing without env vars). It does not explicitly state when not to use the tool or compare to alternatives, but the sibling tools are clearly different in purpose.

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