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

Annotations already declare destructive, open-world, non-idempotent, and non-read-only behavior. The description adds important context beyond them: the operation costs real money and waits for owner approval.

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?

Two tightly packed clauses with the core action and financial consequence front-loaded. There is no wasted language.

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?

The description covers financial cost and approval delay, which are essential for a destructive purchase tool, and annotations supply safety cues. However, with no output schema, it does not explain what the agent receives after approval or what happens while waiting.

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 batch_id, rate_ids, ship_date, label_type, and max_total_usd are already documented. The description only reinforces batch and rate selection, adding little beyond the 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?

States a specific verb and resource: buying labels for a draft batch at chosen rates. An agent can distinguish this from creation tools such as create_batch and pricing tools such as get_rates.

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?

Makes clear this applies to a draft batch and selected rates, with schema fields pointing to create_shipment/create_batch and get_batch as sources. It gives clear context but does not explicitly state when not to use it or name alternatives in the description.

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