get_index_price

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

With no annotations provided, the description must carry the full behavioral disclosure burden. It reveals that the price is cached and that pre-subscription is required, which is useful. However, it does not explain what happens if the agent has not subscribed, whether the cached value can be stale, or what failure/error behavior to expect.

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?

The description is compact and information-dense: one sentence for purpose, one for a critical prerequisite, and a parameter example. Every part earns its place without redundant phrasing or unnecessary detail.

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?

For a simple single-parameter read tool, the description covers the core operation and prerequisite. However, it omits behavior when the subscription is missingtuple, which is a key operational context. Since an output schema exists, return-value explanation is less necessary, but the failure mode remains a notable gap.

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 schema provides no description for the 'symbol' parameter, so the description's clarification that it is a trading pair with the example 'BTCUSDT-PERP.BINANCE' adds meaningful guidance. This compensates well for the 0% schema coverage, though it could mention whether only perpetual symbols are supported.

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 description states a specific action and resource: '获取缓存中的指数价格' (get cached index price). It clearly identifies the operation, but it does not explicitly differentiate itself from sibling tools like get_mark_price or get_ticker, leaving some ambiguity about when the index price is the appropriate source.

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 description provides one important usage prerequisite: '需要先预订阅 index_price' (must pre-subscribe to index_price first). However, it does not state when to use this tool versus alternatives such as get_mark_price, nor does it give any exclusions or alternative routing guidance.

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