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

No annotations exist, so the description carries the full behavioral burden. It reveals sort direction (ascending) and input domain (numbers), but says nothing about input format, whether the original list is mutated, performance characteristics, or return shape.

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 tight and front-loaded, but the appended '🆓 5 free trial calls' promo adds marketing noise rather than operational information, diluting an otherwise efficient description.

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?

With no output schema, no annotations, and an undocumented single string parameter, the description should specify input encoding and return format. It omits both, leaving the agent unable to construct a correct call confidently.

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?

One parameter ('values') with a string type and zero schema description coverage. The description's 'list of numbers' hints at the parameter's content but does not clarify that a string encoding (e.g., comma-separated) is expected, which is the critical ambiguity for this schema.

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 ('Sorts a list of numbers ascending') and names the algorithm (selection sort), which distinguishes it from siblings like x402-bubble-sort, x402-quick-sort, and x402-merge-sort. It doesn't explain why one would pick this algorithm, but the purpose is 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 only extra sentence is a pricing/billing note ('5 free trial calls per signed wallet'), which is not usage guidance. Nothing says when to use selection sort over the many sibling sorts, nor any input constraints or prerequisites.

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