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

Annotations already declare readOnlyHint and openWorldHint, but the description adds genuinely non-obvious behavior: the $0.002 USDC per-call charge, the x402 payment rails (Base, Solana, Arc), and that failed calls are free. That cost/auth context is exactly the kind of information annotations cannot carry. It stops short of noting rate limits or latency.

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?

Two sentences, zero filler. The functional scope leads, and the pricing/payment caveat follows as a distinct clause. Every sentence carries information an agent needs before calling.

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 an output schema present, the description needn't enumerate return fields, yet it still summarizes them. Schema, annotations and cost model are all accounted for, so an agent has everything needed to call correctly and knows the financial cost of doing so.

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's own description already gives the BTC_USDT/ETH_USDT format, so the schema does the heavy lifting. The description's example format and 'one market' phrasing add only marginal reinforcement, matching the baseline 3 for a fully documented parameter.

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 ('WhiteBIT exchange spot ticker for one market'), names the exchange that separates it from the many sibling exchange-ticker tools (bitfinex, bitget, bitstamp, etc.), and enumerates the returned content (last price, 24h change, volumes). An agent can pick this over a neighbouring ticker tool without opening a 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?

The one-market scope ('for one market') implies the calling pattern, but there is no explicit when-to-use/when-not or a named alternative for cross-exchange or multi-market comparisons. Usage is inferable from the exchange name rather than stated.

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