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

Annotations only declare readOnlyHint and openWorldHint; the description adds genuinely non-obvious behavior — a $0.002 USDC per-successful-call charge via x402 on Base/Solana/Arc, and that failed calls are free. That is real cost/auth context an agent needs before invoking. It stops short of disclosing rate limits, caching, or price-refresh frequency, so it is 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?

Front-loads the purpose and keeps the whole definition to three dense sentences with little waste. The 'Related tools on this server, for a different need' preamble is slightly verbose framing but still earns its place via the routing information.

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?

An output schema exists, so return values need no prose, and the description covers scope, cost, and alternatives. The one meaningful omission for a price-list tool is data freshness/update cadence, which an agent may care about when comparing to live ticker siblings.

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 parameter already documents the 1-100 range and default of 10; the description's '(N from 1 to 100)' merely restates it. Baseline 3 applies since the schema does all the semantic work.

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+resource and enumerates the returned fields (USD price, market cap, 24h volume, 1h/24h/7d changes) plus the scope (top N coins, N 1-100). That is specific enough to distinguish it from the oracle and ticker siblings without opening any 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?

Explicitly routes to finance_nomics_crypto for general tickers and finance_dia_crypto_oracle for a single-asset USD price, with the condition that selects each. However, it does not differentiate against the many other equally-similar market-data siblings (finance_coingecko, finance_coinmarketcap, finance_coinpaprika_tickers), so the routing is partial rather than complete.

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