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

With no annotations present, the description carries the full behavioral burden, and it does so well: it discloses the payment model ($0.01 USDC on Base), the endpoint (GET /api/search), and the non-obvious fact that the tool returns a payment resource instead of search results. It omits failure modes, payment-resource lifetime, and post-payment flow, so it falls short of exhaustive.

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?

Front-loads purpose, then the payment mechanic, then parameters — a sensible order with no fluff. The trailing parameter recap is largely redundant against a 100%-covered schema, which is the only thing that keeps it from a 5.

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 6-parameter tool with no annotations and no output schema, the description supplies the essential missing context: what it returns (a payment resource, not results) and the cost/mechanism. It stops short of explaining how to complete the call or what a successful response looks like, leaving a modest 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 description coverage is 100%, so the schema already documents every parameter including defaults, ranges, and optionality. The description merely restates query/count/country/language/page/device with no added syntax, format, or interaction detail, matching the baseline for fully-covered schemas.

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 ("Live web search") and enumerates the result scope: ranked results plus answer box, knowledge graph, people-also-ask and related searches. Critically, it also pins down the tool's odd role — it returns the payment resource rather than executing the search — which separates it from a naive search or from a page-fetch sibling like scrape_url.

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 the context an agent needs to decide whether to invoke: this is a PAID x402 call costing $0.01 USDC on Base, so it should be reserved for cases where live search justifies the spend. There is no explicit naming of alternatives or when-not-to-use, keeping it below a 5.

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