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 pricing ($0.005/call), payment chains accepted (USDC on Arc/Base/Solana, XNT on X1), the x402 auth requirement, and that concentrated/shared-payout cases are flagged. It lacks detail on rate limits or failure modes, but covers the key behavioral traits.

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 front-loaded: the ranking thesis leads, followed by what is returned, flags, and payment mechanics. Every sentence earns its place, though the payment-chain list and workflow sentence are packed 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?

No output schema exists, so the description usefully enumerates the returned signals (payers, payments, USDC, concentration, liveness). Combined with pricing and the payment workflow, an agent has enough to call it correctly; only ranking order ties and error handling are unspecified.

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% and the single `payment` param is documented, so baseline is 3. The description adds genuine value beyond the schema by explaining the two-step x402 flow (fetch terms unsigned, then re-call with the signed payload), which the schema alone does not convey.

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 — ranking Arc agents by distinct OUTSIDE payers read from settlements — and immediately differentiates itself from reputation/market siblings via 'Track record, not price.' An agent can tell what this produces without opening the 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?

Gives clear invocation workflow (call once without `payment` for terms, sign, call again with `payment`), but no explicit when-to-use or when-not-to-use versus siblings like arc_agent_reputation or arc_trust_check. Usage is implied by the ranking semantics rather than stated.

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