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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses the 5 s cache window, the $0.010 per-call cost, and the x402 payment mechanism (USDC on Base or Solana) — real operational context an agent needs before calling a paid endpoint. It stops short of failure modes (what happens if a venue is down) or how deviation is computed.

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 dense sentences, front-loaded with the core capability, then venue/quotation detail, then caching and cost. No filler or repetition of the title beyond the necessary scope statement.

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 names the key return elements (median and max deviation across venues), and it covers cost, caching, and payment. A brief note on response shape or behavior when a venue is unavailable would make it fully 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?

Schema coverage is 100% and already documents symbols, its default, the 20-ticker pattern, and tx as an X-Payment-Tx header alternative. The description adds the useful detail that quotes are vs USDT on four venues and vs USD on Coinbase, which affects interpretation, but it says nothing about the tx parameter. Baseline 3 is appropriate.

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: consensus prices for up to 20 coins aggregated across five named venues, plus median and max deviation. This clearly separates it from single-coin siblings like price/token_price by scale and aggregation, though it never names those alternatives explicitly.

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 rather than stated: the agent can infer 'use this when you want a cross-venue consensus rather than one quote', and the 20-coin cap and 5 s cache imply batching is expected. There is no explicit when-not guidance or routing to price, token_price, candles, or market_overview.

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