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

Annotations only declare the mutation/open-world flags; the description adds the substantive behavior: single USDC payment on Base, same list price as card, no account or checkout, and a permanent download link. It stops short of describing failure/refund behavior or payment-confirmation timing, which would be the remaining gap.

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 short paragraphs, the action and outcome front-loaded, followed by the decision rule. Every sentence carries either purpose, cost logic, or a pointer to a sibling tool; no filler.

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 one-parameter purchase tool with no output schema, the description covers what happens (permanent CSV download), cost model, and prerequisites (get_dataset for pricing). Nothing an agent needs to invoke it correctly is missing.

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 coverage is 100% for the single 'dataset' parameter, so the schema already carries the semantics (slug, example, 'use search_datasets first'). The description adds no parameter-level detail, making the baseline 3 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?

States a specific verb and resource ('Buy an ENTIRE dataset outright') plus the outcome ('permanent download link for the CSV'). It explicitly distinguishes itself from query_locations and get_dataset, so an agent can pick it without opening a schema.

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?

Gives an explicit when-to-use rule ('prefer this over repeated query_locations calls whenever you want most of a file'), quantifies the crossover ('past a few hundred rows'), and routes the agent to get_dataset for price/record count first. Nothing is left to inference.

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