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

With no annotations, the description carries the full disclosure burden, and it delivers almost none: nothing about whether duplicates are collapsed, ordering, how URLs are delimited (punctuation, trailing parens), or what the response shape is. 'Extract URLs from text' merely restates the title.

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?

Two short clauses, front-loaded with the operation and with zero filler. The only waste is the near-duplicate restatement of the title in the first clause.

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 one-parameter text utility with no output schema and no annotations, this is minimally viable: the agent knows what to send. It does not say what comes back (array of strings? count? positions?), which for a URL extractor is the main open question.

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?

There is a single 'text' parameter and its schema description ('Text to process') covers it at 100%, so per the baseline the schema does the work. The description adds no syntax, size, or encoding guidance beyond that.

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?

Names a specific verb (Extract) and resource (URLs) plus the source (from text), so the operation is unambiguous. It does not, however, differentiate itself from near-identical siblings such as x402-extract-emails, x402-extract-numbers, or x402-url-parse.

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 description gives no when-to-use context, no exclusions, and never mentions an alternative such as x402-url-parse (which analyzes a single URL) or x402-validate-url. The agent must infer the routing decision entirely on its own.

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