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

Beyond the readOnly/openWorld annotations, it discloses meaningful behavior: the counting methodology (each service counted once, at its median), that results are signed, and the exact cost/rail ($0.01 USDC per call via x402 on Base or Solana). The payment requirement is material for invocation and is not derivable from 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?

Purpose and scope are front-loaded, and the sentences are dense but each carries distinct information (category definition, methodology, price param, default, signing, cost). Slightly overloaded with the parenthetical examples, but no true filler.

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 previews the return shape (counts, percentiles, trends) and covers the cost and default-tag behavior, so an agent has enough to call it correctly. Minor gaps remain around the price param's accepted input format.

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 must carry both params. It does well for 'tag', giving concrete examples (search, llm, weather, market-data), but 'price' is defined only functionally ('see where a price sits') with no accepted format or type guidance for a string param.

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 ('price benchmarks for x402 services by category') and enumerates the return contents (service count, price percentiles, 7/30-day trends), which is unusually concrete. It does not, however, explicitly distinguish itself from the sibling prices_service, which covers similar ground, so it stops short of a 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?

It gives usage mechanics ('Add price= to see where a price sits'; 'Without tag: every category'), which tells the agent how to invoke it but not when to choose it over prices_service or the other price-related siblings. Tool-selection guidance is absent, leaving the agent to infer the boundary.

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