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 dual-source methodology, the return fields (price, spread, staleness, confidence), the failure mode ('Refused, not charged, if sources disagree over 2.5% or one is missing'), and the cost ($0.002 via x402). It omits auth/rate-limit details, so not 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?

Dense and front-loaded: the core deliverable leads, followed by methodology, return fields, refusal policy, disclaimer, and price. Every clause carries distinct information with no filler.

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?

Despite no output schema, the description enumerates the return fields and the failure/refund behavior, plus cost and a disclaimer, giving an agent everything needed to call and interpret the tool 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 67%, with token and request_id already documented in the schema and chain defaulting to 'base'. The description adds no parameter-level syntax or format detail, so the schema does the heavy lifting and a 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 resource and scope ('Verified USD price for a Base ERC-20') plus the methodology, making the tool's job unambiguous. It is clearly distinguishable from the sibling token_risk, which covers a different concern.

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 implied by the resource (fetch a verified token price) and the refusal condition is spelled out, but there is no explicit when-to-use vs alternative guidance and no mention of token_risk or other siblings. Adequate but with a clear routing gap.

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