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

No annotations are supplied, so the description carries the burden. It does add genuinely useful behavioral context (a free-trial quota of 5 calls per signed wallet, implying a metered/paid service), but it says nothing about what the response looks like, whether duplicates or trailing punctuation are handled, or whether ordering is preserved.

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 core action and followed by the pricing note. The redundant "Extract Urls:" prefix is the only wasted text.

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, annotation-free tool with no output schema, the description covers the action and the billing model but leaves the agent guessing about return shape (list of strings? count?), deduplication, and input constraints. Adequate but with clear gaps.

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 the single `text` parameter, and the description only echoes it via "from text." It adds no detail on acceptable formats (multiline, HTML, markdown), size limits, or whether the field is required — a gap the schema cannot fill for the agent.

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 ("Extract URLs from text"), which is unambiguous. However, it does nothing to distinguish itself from near-identical siblings such as x402-extract-emails, x402-url-parse, or x402-url-inspect, and the leading "Extract Urls:" merely restates the 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?

Usage is only implied by the phrase "from text" — an agent can infer the input must be a string containing URLs. There is no explicit when-to-use guidance, no exclusions, and no routing to siblings like x402-url-parse for structured parsing.

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