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

With no annotations, the description bears the full burden. It does add genuinely useful non-schema behavior — the 5¢ per-call cost paid in USDC on Base — which an agent needs before invoking a paid endpoint. But it omits read-only vs mutating nature, whether results are real-time or delayed, and rate/refresh limits.

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?

One compact line with the identity front-loaded and the bilingual gloss adding disambiguation for Chinese-market queries. It avoids padding, though the terseness edges toward under-specification rather than true economy of 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?

With no annotations, no output schema, and no parameters, the description is the only source of truth, and it leaves the most important question — what the scanner actually returns and how fresh it is — unanswered. Pricing is covered, but an agent still cannot predict the response shape it will pay 5¢ for.

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?

The input schema is an empty object with zero parameters and 100% coverage, so there is nothing for the description to disambiguate. Baseline 4 applies; the absence of any parameter discussion is not a defect here.

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?

The name is an opaque UUID, so the description alone must establish identity, and 'A-share Limit-Up Scanner (A股涨停扫描)' does name a recognizable resource and behavior (scanning Chinese A-shares for limit-up stocks). However, it never states what the scan produces — a list of currently limit-up tickers, a historical log, or an alert feed — so the verb 'scan' stays vague about output.

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?

'For Chinese A-share stocks' sets a market scope but gives no when-to-use condition, no exclusions, and names no alternative among the many finance/market siblings (x402-stock-price, x402-market-pulse, x402-price-screener). An agent knows the domain but not when this tool rather than another applies.

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