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

With no annotations, the description carries the full burden of behavioral disclosure. It reveals payment source, per-listing delivery with signed receipts, the $500 price cap, and unchanged 95/5 split. It does not cover failure modes or partial success behavior, but covers major operational traits well.

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 five sentences, front-loaded with the core purpose. Each sentence adds relevant detail, though the final note about the 95/5 split is tangential for buyers and could be omitted without losing essential operational context.

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 no output schema, the description explains the delivery process and directs the user to poll get_purchase per listing. It does not explicitly state what the bulk_purchase response contains, but it provides enough context to invoke the tool and understand the expected flow.

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 input schema already fully documents all parameters. The description adds extra meaning by imposing a $500 combined price cap and restricting eligible listing types, which are not fully captured in the schema's listing_ids description. This helps validate input choices.

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 the tool's function: 'Buy multiple standard listings (up to 100) in a single charge.' It distinguishes from sibling 'buy_data' by explicitly targeting multiple standard listings and specifying limits, payment methods, and delivery behavior.

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?

Provides clear when-to-use context for bulk purchasing standard listings, and explicit when-not via ineligibility of exclusive, limited, and Personal Health Data listings. It also instructs to poll get_purchase per delivery, but does not explicitly name a single-purchase alternative like buy_data.

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