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

No annotations are provided, so the description must carry the burden. It discloses that the tool is 'Free' and mentions the inclusion of payment instructions (x402, USDC), but does not describe the response format or any permissions needed. For a simple get operation, this is adequate but not rich.

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 a single efficient sentence with an additional 'Free.' indicator. Every word contributes to understanding the tool's purpose and cost, with 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 tool with one parameter and no output schema, the description adequately conveys what the user receives: product details and payment instructions. It could clarify the structure of the response, but given the tool's simplicity, it is sufficiently 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 fully describes the 'id' parameter with an example ('econ-fred'), and the description only repeats 'by id.' Since schema coverage is 100%, the description adds no additional semantic value, so the baseline score of 3 applies.

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: 'Get details and payment instructions... for one product by id.' It uses a specific verb ('Get') and identifies the resource ('product'), and the scope ('one product by id') distinguishes it from sibling tools like list_products.

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 the use case—when you have a specific product id—which differentiates it from listing tools. It does not explicitly name alternatives or provide exclusions, so it's clear but not exhaustive.

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