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

With no annotations, the description carries the full burden, and it discloses little: no indication that this is a pure, side-effect-free computation, no output shape, and no behavior for out-of-range or missing inputs. The only behavioral detail is the '🆓 5 free trial calls per signed wallet' billing note, which is promotional rather than operational.

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 core sentence is efficient and front-loaded, but the trailing '🆓 5 free trial calls per signed wallet' emoji/promo fragment is clutter that does not help selection or invocation.

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 3-parameter tool with zero schema descriptions, no annotations, and no output schema, the description should clarify each input and what is returned (savings amount vs. final price). It gestures at the outputs but leaves the parameter roles and edge-case behavior unresolved.

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 0%, so all three string params are undocumented. The description maps loosely to 'original price' and '0-100 percent', but leaves the third parameter (discount) completely unexplained, and the overlap between 'percent' and 'discount' is exactly the ambiguity the agent needs resolved.

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 ('computes discount savings and final price from an original price and a 0-100 percent'), so the agent knows this is a discount/price arithmetic tool. It is distinguishable from generic siblings like x402-percent-of, though it does not explicitly reference the near-identical x402-discount sibling.

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?

No when-to-use guidance, no prerequisites, and no mention of alternatives such as x402-discount, x402-decrease-by-percent, or x402-percent-of. The agent is left to infer that this is the discount-specific entry point.

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