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

With no annotations provided, the description carries the full burden of behavioral disclosure, yet it only states the bare operation. It does not disclose how input text is provided given an empty schema, what URL patterns are matched, whether results are deduplicated, or what the return value looks like.

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 very short and the operative statement 'Extract URLs from text' is front-loaded. The only waste is the redundant 'Extract Urls:' prefix, which duplicates the tool name, but there is no other fluff.

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 tool with an empty input schema, no output schema, and no annotations, the description must explain how the agent provides text and what to expect in return. It does neither, so an agent cannot reliably determine how to invoke this tool correctly.

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 contains zero parameters, so there are no parameter semantics for the description to elaborate on; the 0-param baseline of 4 applies. The description adds nothing about parameters, but nothing is required.

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 states a specific action — extracting URLs from text — so an agent knows what the tool does. However, it does not differentiate from sibling tools like x402-url-parse or the x402-extract-emails / x402-extract-numbers family, and the 'Extract Urls:' prefix simply restates the tool name.

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 guidance on when to prefer this tool over alternatives such as x402-url-parse or x402-extract-emails, and no exclusions or when-not conditions. The phrase 'from text' only weakly implies the use case, and because the schema has zero parameters, the description never explains how the agent is supposed to supply the text.

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