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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe read operation. The description adds the list of returned fields but does not disclose any additional behavioral traits (e.g., timezone, data freshness, or exact rolling window definition).

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 concise sentences that front-load the tool's purpose and provide a practical use case. No unnecessary filler or repetition.

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 one-parameter tool with an output schema and comprehensive annotations, the description covers purpose, usage, and data fields. The only minor gap is ambiguity about what 'rolling' means (e.g., exact time boundary), but this is acceptable for the tool's simplicity.

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 zero description for instId, so the description must compensate. 'for an instrument' hints that instId is an instrument identifier, but it doesn't specify the format or give examples. The schema's example 'BTC-USDT' covers some of this gap, but the description could be more explicit about what to pass.

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?

Clearly states it retrieves OKX 24-hour rolling stats for an instrument and enumerates the exact fields (open, high, low, last, volume, vol-ccy). It differentiates from sibling tools like 'ticker' or 'candles' by focusing on a rolling 24-hour aggregate.

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?

Provides an explicit use case: 'Use for daily summary on OKX.' This gives context for when to select this tool. However, it does not mention alternative tools or exclusions, so it's not a full when/when-not statement.

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