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

With no annotations, the description carries the full burden and does so well: it discloses venue coverage, hourly sampling, per-window metrics, failure handling, partial-failure behavior, and the fact that failed calls are not charged. It also states the exact cost of $0.003 USDC per call, which is important for agent decision-making.

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 dense but front-loaded: it starts with the core purpose, then adds sampling cadence, accepted symbol formats, error behavior, and cost. Every sentence provides actionable context, and there is no redundant restatement of the tool name or title.

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?

There is no output schema and no annotations, so the description must explain enough for correct invocation. It covers what is returned, which venues are queried, the time windows, sampling frequency, accepted symbol formats, partial-failure reporting, complete-failure semantics, and pricing. That is sufficient for an agent to understand the tool's behavior and result shape.

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%, so the single symbol parameter is already documented. The description still adds value by clarifying that the tool accepts base assets or pairs in multiple formats, including BTC/USDT and the alternate XBT ticker. That goes beyond the schema examples of BTC, ETH, and SOLUSDT.

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 verb and resource: how one asset's perpetual-futures open interest moved over 1, 4, and 24 hours across OKX, dYdX, and Kraken Futures. It also scopes the data precisely, including current OI, change amounts and percentages, price change, and a combined cross-venue view. Although it does not name sibling tools, its focus on OI change is clearly distinct from broader siblings such as perp_market_overview.

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 makes the tool's use case clear: analyzing short-term open-interest movement and its conventional market interpretation. However, it does not explicitly say when to use this tool versus alternatives such as perp_market_overview or funding_rate_arbitrage. Usage is therefore implied rather than explicitly guided.

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