chitchats_buy_postage

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose a key trait: this is an async operation, and advises checking shipment status afterward. However, it omits other important details such as side effects (financial transaction), failure modes, or whether the shipment must be in a particular state. The disclosure is partial.

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 two short sentences, front-loaded with the core action and followed by a critical behavioral note. Every sentence serves a purpose, and there is no redundant or filler content.

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 simple one-parameter tool with no output schema and no annotations, the description covers the essential action and the important async follow-up. It lacks explicit prerequisites or success/failure details, but given the tool's simplicity, the description is sufficiently complete for basic usage.

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?

The schema already describes the only parameter 'id' as 'Shipment ID' with 100% coverage. The description adds no extra parameter semantics beyond the schema, so the baseline score of 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 states a specific action: 'Purchase postage for a shipment.' This clearly identifies the verb (purchase) and resource (postage for a shipment), and distinguishes it from siblings like get_rates or create_shipment. The async note adds a unique behavioral trait that further disambiguates it.

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 implies usage: you have a shipment and need to purchase postage. It provides a follow-up instruction ('check shipment status after') but does not explicitly mention when to use this tool versus alternatives, nor does it give exclusions or prerequisites. Guidance is minimal but not misleading.

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