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

Annotations already cover read-only, idempotent, and non-destructive aspects, lowering the bar. The description adds meaningful context by specifying the return fields and the USDC integer base units (6 decimals), which clarifies the output format without contradicting annotations.

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 concise, packing the API endpoint, purpose, and return fields into two sentences with no redundant content. It is well-structured and easy to parse quickly.

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 explains the core purpose, lists the output fields, and clarifies the unit of amounts, which gives sufficient context for basic usage. It does not delve into fee calculation details or error conditions, but given the schema and annotations, it is reasonably 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 provides full descriptions for both parameters (sellerId and since), including constraints and units. The description does not add additional meaning beyond what is already in the schema, so it meets the baseline without enhancing understanding.

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: computing a seller's platform-fee invoice from settled receipts. It distinguishes from sibling tools by specifying the invoice calculation and the endpoint, which is specific and unambiguous.

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 when to use the tool (when an invoice is needed from settled receipts) but does not explicitly contrast with alternatives like get_seller_analytics or list_services. No direct 'when not to use' guidance is provided, so it relies on implied context.

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