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

No annotations exist, so the description carries the full burden. It does add genuinely useful non-annotation context (5 free trial calls per signed wallet), but omits the important behavioral facts: what input format is expected, whether large k is capped or errors, and how results are returned.

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?

One front-loaded sentence stating the operation, followed by a short promotional note. No wasted prose, though the emoji/trial tagline is noise for an agent selecting a tool.

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 utility with no output schema, no annotations, and 0% parameter documentation, the description leaves the agent unable to construct a valid call confidently - input encoding and result shape are both undefined.

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% and both parameters are typed only as 'string', so the description must compensate. It only loosely implies k is the length and values is the source set - it never clarifies how multiple values are encoded in a single string (CSV, JSON array, whitespace) or whether k is parsed as an integer.

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 precise verb+resource: 'Enumerates all k-length permutations of the input values.' This distinguishes it from x402-permutation-count (counting) and x402-combinations (unordered), though no sibling is named explicitly.

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?

Usage is implied by the mathematical task itself - an agent needing ordered arrangements of k items would select this. However, there is no explicit when-to-use, no exclusion (e.g., use permutation-count if you only need the number), and no guidance on size limits that make enumeration impractical.

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