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

With no annotations, the description carries the full burden, and it does add real behavioral facts: the catalogue is 'live', results include ids/names/endpoints/prices, and queries are capped at 500 characters. However it says nothing about the x402 payment/auth model, cost, rate limits, result count caps, or pagination — significant gaps for a paid catalogue search.

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 tight sentences, front-loaded with the action and scope, followed by the sibling comparison. Nothing is redundant and the distinguishing detail is placed where the agent will read it.

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 annotations and no output schema, the description usefully enumerates the returned fields and the query limit. But for a tool with five aliased parameters and an implicit paid-catalogue access model, it leaves the agent guessing on how to actually form the call, so it is only minimally sufficient.

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 exposes five optional string parameters (q, text, query, search, keyword) whose descriptions are vacuous placeholders ('Q to process', 'Text to process'), so the nominal 100% coverage conveys no meaning. The description mentions 'up to 500 characters of query' but never explains that the five names are aliases or which one to send, leaving a genuine ambiguity unresolved.

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 names a specific verb and resource — keyword search over the live x402 service catalogue — and states exactly what comes back (service ids, names, endpoints, prices). It also explicitly distinguishes itself from the sibling x402-find by noting the longer query limit, so an agent can choose between them without opening either schema.

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?

It routes the agent by naming the alternative (x402-find) and the condition that selects this tool (a longer query, up to 500 characters). There is no explicit when-not-to-use or prerequisite guidance (e.g., payment/auth requirements), so it falls short of a 5.

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