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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'Nothing is purchased, created or printed', so there is no contradiction. It adds useful operational context (account pickup default, courier prerequisite, endpoint) beyond the annotations, though it doesn't cover rate behavior like carrier response variance or error handling.

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?

Front-loads the critical 'QUOTE ONLY' constraint, then layers returned fields, side-effect exclusions, defaults, and prerequisite in tight sentences with no filler. Every sentence carries distinct information.

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 nested-parameter quoting tool with no output schema, the description names the return fields and the read-only guarantee, making it callable without guessing. Minor remaining gap is the unmentioned currency parameter, but overall it is nearly complete.

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 75%, so the schema already documents most fields including units and the sender default. The description adds little beyond restating destination, parcels, and the sender default that the schema already carries, and never mentions the currency parameter.

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 (quote) and resource (shipping rates), spells out what is returned (service name, code, price), and scopes it to a destination, parcels, and account-enabled couriers. This clearly distinguishes it from the order-mutating siblings like starshipit_create_order.

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?

'QUOTE ONLY' plus 'Nothing is purchased, created or printed' tells the agent exactly when this applies versus a create tool, and 'Needs at least one enabled courier' gives a prerequisite. It stops short of naming an explicit alternative tool, but the exclusion of write behavior is clear.

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