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

The annotations already mark it read-only and non-destructive, and the description adds meaningful context beyond that: rates are normalized to an hourly figure and annualized across venues, and positive funding means longs pay shorts. It also explains differing settlement cadences, which affects how an agent interprets the returned values.

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 informative and front-loaded, starting with the core function before use cases and cost. There is slight redundancy around 'hourly' and annualization, but no sentence is dead weight.

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 one-parameter, read-only data tool with no output schema, the description names every returned component, explains normalization for comparability, gives the sign convention, and states intended use cases. An agent has enough context to invoke it correctly and interpret the result.

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 fully documents the only parameter, including a pattern and examples, so the description does not need to add much. The description only confirms that the tool is coin-specific, matching what the schema already states. The baseline of 3 is appropriate.

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 opens with a specific resource and function: perpetual funding for a coin across Hyperliquid, OKX, and Kraken Futures. It also enumerates the exact outputs (per-interval rate, annualized APR, open interest, mark price), making the tool's role distinct among the many market-data siblings.

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 explicitly says 'Use for basis/carry trades or crowding signals,' giving an agent a clear selection criterion. It does not name alternatives or state when not to use it, so it misses the top score but is well above providing no guidance.

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