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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses a paid, signed, weekly-refreshed census: $0.01 USDC per call via x402 (Base or Solana) and 'Signed.' These are material operational traits (cost, payment rail, auth/signing) an agent must know before invoking.

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 the census scope, then the filtering behavior, then payment terms. Dense but largely waste-free; the payment/signing sentence earns its place given the tool is metered.

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 wisely describes what gets measured, and it covers cost and signing. But the undocumented 'platform' parameter and lack of return-shape/pagination detail leave gaps for a data-query tool with two free-form string 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 must carry parameter meaning. It explains signal= and gives an example (signal=ucp) with ordering behavior, but the second parameter (platform) is never mentioned, leaving half the inputs undocumented in both schema and prose.

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: a weekly census of 65,000 top sites measuring UCP/ACP agent-checkout profiles, agent/MCP cards, llms.txt, crawler blocking, store platforms, and 30-day changes. The scope is concrete enough that an agent can distinguish it from generic readiness siblings without opening a 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 implies usage through 'With signal=, the stores that have it (for example signal=ucp), most-linked first,' which tells the agent how to pivot to a filtered view. However, it never states when to prefer this over sibling tools like web_readiness or commerce_stores, so the alternative-selection guidance is left to inference.

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