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

Adds substantial context beyond the readOnly/openWorld annotations: a 15-second cache, the behavior that unpriced symbols land in 'unavailable' rather than erroring, a per-price source attribution, and a concrete cost model ($0.002 USDC per successful call via x402; failures are free). The payment requirement is exactly the kind of trait an agent must know before invoking.

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 but front-loaded: capability first, then edge-case behavior, then cache/cost. Nearly every sentence earns its place; the 'Information only, not financial advice' clause is the one near-filler line, though it is arguably relevant to an agent relaying prices.

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 shape need not be explained, and the description still covers source attribution and the 'unavailable' bucket. Combined with cache TTL, provider selection, and x402 payment terms, an agent has everything needed to decide, pay, and interpret results.

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 100%, so the single 'symbols' parameter is already fully documented (comma-separated, up to 20, Solana mint addresses accepted). The description largely restates this, adding only the fallback behavior for symbols with no price. 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 verb+resource ('USD spot prices'), quantifies the batch ('up to 20 symbols') and names the data sources (Coinbase for symbols, Jupiter for Solana mints). This clearly separates it from sibling tools like crypto_candles (OHLC history), crypto_convert (conversion) and solana_quote (single-mint dex quote).

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?

The batch-of-20 and 'USD spot' framing implies when this tool is the right pick, but the description never explicitly routes the agent to or away from alternatives such as crypto_candles, crypto_convert or solana_quote. There are no stated exclusions or prerequisites for use.

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