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

It discloses that data is published keylessly (no authentication) and hints at the output (annualized rates and spread). However, with no annotations, it should also mention rate limits, error handling, and response structure. These are absent, leaving a significant gap for an unannotated tool.

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 verbose, with a metaphorical explanation of funding ('the difference between a carry trade that works and one that bleeds') that is not essential. It front-loads the core purpose but includes unnecessary elaboration, making it longer than needed.

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 tool with no output schema and four parameters, the description is incomplete. It does not explain the return format, the meaning of three out of four parameters, or any constraints like symbol format or rate limits. The absence of output schema places a high burden on the description, which it fails to meet.

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 description clarifies the `symbol` parameter by stating it can check one asset, but it does not explain `limit`, `instrument`, or `minSpreadPct`. The schema descriptions are generic placeholders, so the description only partially compensates for the lack of parameter meaning.

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 retrieves hourly funding rates from Polymarket Perps and Hyperliquid and computes the annualized spread between them. It differentiates from single-venue tools by noting 'one call can do what no single-venue service can.' However, it uses jargon like 'priced for carry' which may be ambiguous, so it's not a perfect 5.

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 implies usage for cross-venue funding comparison and mentions 'Optionally pass symbol to check one asset,' but it does not explicitly name alternatives or state when not to use this tool. There is no clear guidance on selecting between this and sibling tools like x402-hyperliquid-funding.

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