Who paid an agent, and whether its reviews come from payers (free)

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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior, yet the description adds real interpretation context: the 250 cap, that observed payers are a lower bound, and that payment-grounded reviews are not independent because a same-operator payer grounds its own reviews. Those caveats materially affect how an agent reads the result.

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?

Three sentences, each carrying load, with the resource definition front-loaded. The first sentence is extremely dense and jargon-heavy, which slightly hurts scannability, but nothing is padding.

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 carries the return-shape burden and does so, naming payments, USD, first/last paid, and the feedback grounding measure. Combined with the cap and independence caveats, an agent has enough to call and interpret it, though the dense jargon leaves some ambiguity.

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 both agent and limit. The description restates the 250 ceiling and USD ordering rather than adding new syntax or format detail, so the 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?

The description states a specific verb+resource: the wallets observed paying one agent, plus how much of its ERC-8004 feedback is payment-grounded. An agent can tell it returns a payer set with USD/timestamps and a grounding ratio, distinct from siblings like agent_record or pay_check. Sibling differentiation is implicit rather than explicit, so it falls 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 a downstream usage tip (pass the addresses as clientAddresses to getSummary to read only paid reviews) but never states when to choose payer_set over siblings such as counterparty_preview or agent_independence. Usage is implied by the returned data rather than framed as a decision rule.

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