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

With no annotations and no output schema, the description carries the full burden: it usefully discloses the return shape (JSON array) and number forms captured (integers, decimals, leading minus). It also discloses a commercial constraint ('5 free trial calls per signed wallet'), which is genuinely behavioral context. However, edge cases are unaddressed—unbounded params, empty input, whether extraction is order-preserving, and how thousands separators or scientific notation are treated.

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 with an inline example that does real work by showing sign handling; nothing bloated. The trailing trial-call line is promotional but does convey pricing, so it is not pure waste.

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 trivially simple parser the description is nearly sufficient, and no output schema is needed since the return shape is stated. The unresolved dual-parameter ambiguity and undocumented edge-case behavior are the remaining gaps for a tool with zero annotation and zero schema-description support.

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 description coverage is 0% for two string parameters named 'text' and 'input', and required is empty. The description refers only to 'text', leaving the duplicate 'input' parameter completely unexplained and the choice between them ambiguous.

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 ('Pull every number out of text') and pins it down with a concrete input/output example ('a1 b-2.5' becomes [1, -2.5]). It does not name the inverse sibling x402-strip-numbers or any other near-neighbor, so an agent must infer differentiation from names alone.

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?

There is no when-to-use or when-not-to-use guidance and no named alternative. The only implicit signal is the example, which shows a parse task rather than telling the agent to pick this tool over x402-strip-numbers, x402-number-report, or x402-regex-test.

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