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

No annotations are supplied, so the description carries the full behavioral burden. It does disclose the shape of the result set (ids, names, endpoints, prices), which is genuinely useful given there is no output schema. It says nothing about payment/auth requirements, result ordering, pagination beyond the limit cap, or rate limits — meaningful gaps for a tool in a paid x402 ecosystem.

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?

A single front-loaded sentence that leads with the action and resource, then the return payload, then the accepted inputs. No filler, no restatement of the tool name, nothing that fails to earn its place.

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 six-parameter tool with no annotations and no output schema, the description does the right things — it explains the result fields and two of the inputs — but leaves the alias parameters and any auth/payment preconditions unaddressed. Adequate to attempt a call, not complete enough to call it confidently.

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 nominally 100% but the per-parameter text is boilerplate ('Q to process', 'Query to process'), so the schema adds essentially nothing. The description partially compensates by naming q and giving the 1-20 limit range, which the schema omits. However, four alias parameters (text, query, search, keyword) are left completely unexplained, so the agent cannot tell whether they are synonyms or distinct filters.

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+resource: keyword search over the live x402 service catalogue, and even enumerates the returned fields (service ids, names, endpoints, prices). That is clear enough for an agent to know what it does. It stops short of differentiating itself from close siblings such as service_discovery or x402-search, which is the only thing keeping it out of the top band.

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 guidance, no when-not-to-use, and no named alternative among the many discovery-oriented siblings (service_discovery, x402-token-search, x402-search). An agent is left to infer that this is the general catalogue-lookup entry point. Pure capability statement with no routing help.

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