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

Annotations only declare readOnlyHint and openWorldHint, so the description carries the real behavioral load and does so richly: exact cost ($0.004 USDC per call over x402), failed-call billing behavior, the quote-then-sign two-step handshake, and a per-day free allowance that needs no wallet. These are consequential traits the agent cannot infer from the annotation block.

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 purpose and returned fields, then pricing and payment mechanics. Two tight paragraphs with no filler, though the parenthetical warning list is dense and could be trimmed without losing meaning.

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 must describe returns and it does — enumerating what the warnings and price/liquidity sections contain per chain. Combined with the payment/cost details, nothing an agent needs to invoke this correctly (including the quote-first flow) is missing.

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 baseline is 3, but the description adds value beyond the schema: it names the three supported chains and their default, clarifies token as an ERC-20 contract or SPL mint, and explains the otherwise-cryptic `payment` parameter's role in the quote workflow.

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 (check) and resource (token) and enumerates the actual output: identity, USD price, liquidity, and chain-read warnings (owner, upgradeability, mint/pause/blacklist/fee powers, Solana mint/freeze authority). This scope implicitly separates it from price-only siblings like token_price and token_info, but it never names an alternative to anchor the distinction 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?

Gives a clear when-to-use trigger ('before buying, sending or accepting it') and, unusually, operational guidance for the payment flow: call without `payment` to get a quote, then sign and call again; failed calls are free; first 3 calls/day are free. It stops short of explicitly excluding or comparing against adjacent siblings such as pretrade_check or token_info.

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