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

Beyond the annotations (openWorld true, idempotent false, readOnly false), the description discloses the genuinely useful behavioral facts: it is a chained two-step call, it short-circuits and stops if the registry page does not name the entity, and it costs $0.10 USDC per call via x402. The per-call payment explains the non-idempotent hint. It does not describe what happens if the oracle lookup itself fails, which keeps it below 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?

Three short sentences, front-loaded with the action, followed by the abort condition and the price. No filler, no repetition of the tool name, and the parenthetical cost is compactly placed at the end.

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?

For a paid composite tool with no output schema, the description omits what the BlindOracle trust record actually returns (fields, verdicts, score) and whether partial results are surfaced when the registry check passes but the oracle step yields nothing. The core mechanics and cost are covered, so it is adequate but not complete.

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?

With only one parameter at 100% schema coverage, the baseline is 3, and the description does not raise it. The schema text ('Task/query text for this SKU') is generic boilerplate and does not say how the target entity should be expressed, and the description likewise never clarifies whether the entity name goes in the task string or what format it expects.

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 names a specific two-stage operation: verify the entity against a public registry, then fetch its BlindOracle trust record. That is a clear verb+resource statement an agent can act on. It does not explicitly distinguish itself from near-siblings such as data.business-registry, reputation.lookup, or procurement.trust-layer, 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?

Usage is only implied: an agent can infer this is for entity trust verification when both a registry presence and an oracle trust record are needed. There is no explicit when-to-use, when-not-to-use, or named alternative for the single-source cases (registry-only or reputation-only), which are covered by sibling tools.

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