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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds high-value behavior beyond that: it is a paid x402 endpoint at $0.004 USDC on Base or Solana, it requires an X-PAYMENT header, and X-Trial: 1 yields free trial calls. It does not describe failure modes on payment rejection, which keeps it from a 5.

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 sentences, front-loaded with the purpose and return fields before the payment constraints. The parenthetical field list and the dual-chain pricing detail are dense but each earns its place. Slightly compressed notation (X-PAYMENT, x402) assumes reader familiarity, but no sentence is wasted.

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 usefully lists the response fields and the 20-item ceiling, and it discloses the payment requirement that would otherwise block invocation entirely. However, for a tool with 5 parameters at 0% schema coverage, it leaves the q/query and gl/location duplication unexplained and gives no query syntax or location format. Complete on cost and returns, incomplete on inputs.

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 0%, so the description carries the full burden, and it only implies that a query string and a numeric cap map to the parameters. It says nothing about the apparent duplicates: both 'q' and 'query' exist, as do 'gl' and 'location', and the description never says which to use or whether gl is a country code versus a free-text locality. That ambiguity is exactly what the description should resolve and does not.

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 resource (Maps/places results) and enumerates the returned fields (name, address, rating, phone, website, lat/lng), plus a hard cap of 20 results per query. That is enough to separate it from generic siblings like web_search or news_search. It stops short of explicitly contrasting with those siblings, so it lands at 4 rather than 5.

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 statement of when to prefer this over siblings such as web_search, answer, or map_site, and no prerequisites or exclusions. The only conditional content is payment mechanics, which is invocation detail rather than usage guidance. An agent must infer the use case from the name alone.

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