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

With no annotations, the description must disclose all safety/relevant behavior. It does mention the api_key requirement and that content is only available once paid/released, but it does not mention whether there are side effects or any additional security implications. Adequate but not thorough.

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 concise sentences with the main action and key details front-loaded. Every part adds value, and there is no redundancy.

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 read tool without an output schema, the description covers the key return elements, the condition for content delivery, and the authentication requirement. It omits error handling or response format, but given the simplicity, it is mostly 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?

The schema already describes api_key, and the description adds that it is the buyer's key needed for delivery. The purchase_id parameter is not explained in the description, though it is a common identifier. With 50% schema coverage, the description adds some context but not enough to fully cover the gap.

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 retrieves a purchase's status, receipt, and delivered content. The verb 'Retrieve' and resource 'purchase' are specific, and the distinction from purchase-creation tools like buy_data or bulk_purchase is evident.

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 use after a purchase and notes the 'paid/released' condition, plus the api_key requirement. However, it does not explicitly compare with alternative tools or state when not to use this tool, so guidance is mostly implied.

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