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

Adds rich behavior beyond annotations: live on-chain reads, spot (not time-averaged) prices, graceful handling of pool-less tokens via 'unpriced' instead of failing, plus a specific cost ($0.005 in USDC on Base via x402). The x402 payment explains why readOnlyHint=false despite the read-like operation.

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?

Purpose and chain scope are front-loaded, and each sentence carries distinct information (mechanism, edge-case handling, pricing caveat, cost). Dense but slightly long, with the pricing/payment detail repeated across two sentences.

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 proactively explains return content (pool, reserve, thin-liquidity flag, unpriced bucket) and the cost model. An agent has everything needed to call and interpret the result 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 coverage is 100%, so both parameters (addresses, chain) are already documented, and the description's 'up to 20 tokens' merely echoes the 1-20 schema constraint. No additional format or syntax detail beyond the schema, so 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 (price in USD) plus resource (ERC-20 tokens), with scope (up to 20, four named chains) and mechanism (deepest Uniswap v3 pool vs USDC/WETH). This differentiates it from the singular sibling price_token and from report/audit tools at a glance.

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 a concrete when-to-use ('value a basket of tokens or refresh a watchlist in one paid call'), which the plural batch scope supports. It does not explicitly name price_token as the singular alternative or state when-not to use, so it stops short of full routing guidance.

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