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

Beyond the readOnlyHint and openWorldHint annotations, the description adds valuable behavioral context: every figure is a count with its definition, no entry is scored/rated/labelled, answers come from a dated weekly snapshot, and the tool is free. This fully discloses what the agent can and cannot expect, with no contradiction to annotations.

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 description is three sentences, each earning its place: the first states the core function and outputs, the second clarifies the data's neutral nature, and the third addresses freshness. It is front-loaded and avoids redundancy.

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 covers the main return fields (price, chains, usage counters) and the snapshot date, which is sufficient for an agent to know what to expect. It could mention ordering or pagination, but those are minor given the limit parameter and the tool's straightforward search nature.

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 input schema already covers 100% of the parameters with detailed descriptions (e.g., q has whole-word matching and no stemming, limit has range, network gives chain id format, max_price is in USDC). The description adds no additional parameter-level meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 states a specific verb ('Searches'), a clear resource ('x402 resource catalogue'), and enumerates what it returns (matching paid endpoints with price, chains, and 30-day usage counters). It clearly differentiates itself from the sibling tools, none of which are resource-search tools, so an agent can immediately recognize this as the catalogue lookup.

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 gives a clear context for use — searching for paid x402 endpoints — and includes the useful note that omitting q lists resources with the broadest paying base. It does not explicitly name alternatives or state when not to use it, but no sibling performs an equivalent catalogue search, so the absence of exclusion guidance is a minor gap.

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