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

Annotations already cover readOnly/idempotent/openWorld, and the description adds genuinely non-obvious behavior: the three verdict outcomes with reasons, the exact checklist of sources consulted, and, critically, the $0.02 USDC x402 cost per call. It does not describe failure behavior (e.g., what a verdict looks like if the account is unreachable), which is why it isn't 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?

A single front-loaded sentence leads with the verdict and its allowed values, then the checks, then price. It is dense but every clause carries a distinct signal; only the parenthetical price note could have been folded in more tightly.

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 still specifies the return shape (allow/warn/block with reasons) and the inputs that modulate it. Combined with annotations and full schema coverage, an agent has everything needed to decide to call it and interpret the result.

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 coverage is 100%, so all five parameters, including the vault/account/network/minAgeDays/codeWindowHours defaults, are already documented in the schema. The description restates the vault behavior and the 72 h code window but adds no syntax or edge-case guidance beyond that, 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?

States a specific verb+resource (counterparty-risk verdict for a NEAR account) and enumerates the signals it checks (OFAC SDN, deny-lists, account existence/age, contract code churn, publisher-upgradeable contracts, vault denylist/payment history). The NEAR scope directly distinguishes it from sibling counterparty_risk_evm.

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?

"For use before paying it" gives a clear triggering context, and the NEAR naming plus the vault parameter show when it applies. It never explicitly names counterparty_risk_evm as the alternative for EVM accounts, so the routing is inferred from the suffix rather than stated.

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