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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It discloses nothing: no return format, no edge-case behavior, no side effects, no prerequisites, and no operational context. The text is an empty shell that adds zero behavioral information.

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 short, but this is under-specification rather than conciseness. The eight-word 'Contains Any: Contains Any' carries no information beyond the tool name itself — every sentence (and every word) is wasted repetition.

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 annotations, no output schema, an empty input schema, and a purely tautological description, an agent has no basis to select, invoke, or interpret the result of this tool. The definition is completely inadequate even for a tool of trivial complexity.

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 is empty (0 properties, 0 required, 100% coverage) and the description adds nothing beyond the name. Although the 0-param baseline is lenient, a tool named 'contains-any' clearly requires some input to operate, and neither the schema nor the description indicates how an agent should supply a value. An agent cannot determine how to construct a valid call.

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 is 'Contains Any: Contains Any' — a verbatim repetition of the tool name with no explanatory content. It does not state what operation is performed (string containment, array membership, collection check) or on what resource, and among roughly a thousand x402-* siblings it is completely indistinguishable.

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 usage guidance is provided whatsoever. The description never mentions when to use this tool versus closely related siblings like x402-ends-with-any, x402-line-contains, x402-substring-before, or the many is-* validators, nor any conditions or exclusions.

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