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

Annotations already indicate readOnlyHint=true and openWorldHint=true. The description adds important behavioral context: 'each costs an orderbook call' from the param default description, revealing computational cost. It also mentions snapshots, hinting at data recency. No contradictions with annotations.

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 sentences: first defines the core output and methodology, second contrasts with sibling. No unnecessary words, efficiently front-loaded with key information.

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?

Despite no output schema, the description lists key outputs: annualized net carry, break-even holding period, and 7d stability score. It does not detail return structure or field names, but for a computed metric tool, this is sufficient. The open world hint and parameter cost information round out completeness.

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% with clear descriptions. The description adds context linking 'size_usdc' to 'at your size' and the computational cost of 'top_n' (each costs an orderbook call). This enhances understanding beyond the schema alone.

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 clearly states the tool calculates funding carry NET of costs, including annualized funding minus spread and slippage, break-even holding period, and 7d stability score. It also explicitly contrasts with sibling get_top_funding_rates which shows gross, making the purpose unambiguous.

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 contrasts with get_top_funding_rates, stating 'nobody trades gross', which implies this tool should be used for net carry calculations relevant to trading. It does not provide explicit when-not-to-use scenarios, but the sibling comparison effectively guides usage.

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