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

Annotations only cover safety (readOnly, idempotent, openWorld); the description adds substantive behavior beyond that: 60 s cache, Binance/Jupiter fallbacks, 0.002 USDC x402 pricing with no account or API key, invalid input rejected before payment, failed runs never charged, and PaymentRequired returned without payment. This is exactly the non-obvious operational context an agent needs.

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 identifier forms are front-loaded in the first sentence, then returns, then cost/safety terms. Density is high and nearly every clause carries information, though the free-sample and HTTP-URL tail is auxiliary rather than essential.

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 compensates by enumerating the returned fields (price, 24h change, high/low, market cap, volume, rank, source). For a 2-parameter read-only tool, the pricing, caching and failure semantics leave nothing important unexplained.

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 the baseline is 3, but the description adds a real constraint not present in the schema: the 25-asset cap. It also restates the accepted identifier forms (ticker vs. Solana mint) and names example quote currencies beyond the schema's parenthetical.

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 ('live prices ... for up to 25 assets') and enumerates accepted identifier forms: CoinGecko id, ticker symbol, and Solana mint address. An agent can tell this apart from sibling tools like crypto_trending or solana_token_check 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 usage context: batch up to 25 assets in one call, use get_example for a free sample, and an equivalent HTTP endpoint. It does not explicitly say when to prefer crypto_trending or solana_token_check instead, so the sibling routing is implied rather than stated.

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