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

With no annotations, the description carries the full burden and does well: it discloses the paid model ($0.002 USDC on base, no account/API key/invoice), the exact two-call payment handshake, and a non-obvious data caveat ('Counts are per receiving wallet, so one operator on several hostnames shows the same totals on each'). It omits error/failure behavior and rate limits.

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?

Dense but well front-loaded: the pricing/access model comes first, the call protocol second, the returned data and its caveat last. Every sentence carries information.

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?

No output schema and no annotations, yet the description names exactly what is returned (payment count, distinct paying wallets, first/last seen) and flags the per-receiving-wallet aggregation. That is sufficient for an agent to invoke and interpret it correctly.

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% and the schema already explains both `target` and the optional `payment` header, including 'Omit it to receive the payment requirements... supply it to be served.' The description largely restates that handshake, so baseline 3 applies.

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 concrete verb+resource: 'On-chain payment evidence for one service: how many payments, how many distinct paying wallets, first and last seen.' The phrase 'Read off the chain, not off a claim' implicitly distinguishes it from claim-based siblings like get_trust_score, but no sibling is named explicitly.

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?

The two-step invocation protocol is spelled out ('Call without `payment`... then call again with `payment`'), but there is no guidance on when to choose this tool over adjacent siblings such as get_trust_score, get_service_report, or price_check. Usage is implied rather than framed against alternatives.

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