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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real context beyond that: it is free to call, it returns routing data (x402 path) plus per-call price, and it enumerates catalog contents including price points. It stops short of describing the response shape or whether results are ranked.

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 opening 'Free. Find the right paid AUN utility…' is well front-loaded. But the long parenthetical enumerating eight $0.001 primitives (json.validate, url.parse, text.slugify, …) is catalog inventory that doesn't help an agent select or invoke the tool and crowds out more useful routing guidance.

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 output schema, the description must carry the return-value burden and does so partially: it says you get an x402 HTTP path and a price. It doesn't say what the response container looks like (single match vs ranked list, field names), though for a two-param, no-required-param lookup that is a minor gap.

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 coverage is 100% and both params are self-documented, so baseline is 3. The description earns an extra point by supplying a worked example value ({"task":"research a vendor company website"}) that shows the expected phrasing of a plain-language task, which the schema only gestures at.

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 — find a paid AUN utility and return its x402 HTTP path and price — which is more concrete than a generic search. However, it never distinguishes itself from the sibling search_utilities or get_utility_details, which look like direct competitors for the same job, so an agent can't tell from the text alone which to call.

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?

Gives one concrete usage rule — 'Omit task for the full catalog' — and an example task phrasing, which helps. It offers no guidance on when to choose this over search_utilities or get_utility_details, and no exclusion criteria, leaving sibling selection to inference.

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