最新成交价

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

注解已经声明 readOnlyHint 和 openWorldHint，因此安全性和网络属性已覆盖。描述补充了返回值字段 symbol 和 price（number 类型），但未说明数据时效性、缓存或异常行为；对这类简单查询可接受。

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?

描述仅两句，第一句即点明核心动作和对象，第二句说明返回值，信息密度高且无冗余。结构十分简洁高效。

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?

工具本身只有一个参数，且存在输出 schema，返回结构不必由描述完整展开。整体说明足够支撑调用，但缺少 symbol 写法和命名惯例，因此略距“完全完整”一步。

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 覆盖率为 0%，描述必须承担参数语义。描述中“交易对”暗示 symbol 代表交易对，但没有说明 symbol 的具体格式（如 BTCUSDT 还是 BTC/USDT），也没有任何约束说明。描述未能充分弥补缺少参数文档的问题。

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?

描述明确指定了动作和资源：获取指定交易对的最新成交价。成交价一词能与同类的 market_mark_price、market_24hr_ticker 等工具自然区分，但没有显式点出替代工具，因此略低于最高分。

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?

描述没有说明何时应使用本工具而不使用其他市场数据工具，也没有排除性说明，例如不需要深度数据时使用 market_price、需要标记价格时使用 market_mark_price 等。使用场景只是隐含在名称和描述中。

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