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

The description goes far beyond the annotations by disclosing read-only nature ('Does not place orders, move funds, or mutate your exchange account'), caching ('~1800s'), authentication methods (X-Api-Key or x402 payment proof), rate limits ('60/min'), and billing details ($0.001 USDC per successful call). No contradictions with annotations are present.

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 front-loaded with the core purpose but is overly verbose and repetitive. The exact phrase 'Current and predicted perpetual futures funding rates across all major exchanges via Coinglass with 30-min cache' appears twice (first sentence and the 'Purpose:' line). While the detailed sections (Auth, Cost, Rate limit, Guidelines) are useful, redundancy and length make it less concise than ideal.

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?

The description is highly complete for the tool's complexity: it covers purpose, behavior, auth, cost, rate limits, return summary, and usage guidelines. Given that an output schema exists, the description need not detail return values further. The only minor gap is the absence of explicit 'when not to use' beyond the fill caution, but overall it is sufficient for selecting and invoking the tool.

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 input schema already provides 100% coverage of the two parameters with clear descriptions. The description adds minimal extra meaning, only confirming that __x_payment is 'not a business parameter' and that symbol defaults to 'all major'. Since schema coverage is complete, the baseline of 3 is appropriate; the description does not significantly enhance parameter understanding.

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's purpose: 'Current and predicted perpetual futures funding rates across all major exchanges via Coinglass with 30-min cache.' It specifies a distinct resource (funding rates), the data source (Coinglass), and scope (all major exchanges), making it unambiguous and distinguishable from sibling tools.

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 'Guidelines' section explicitly tells when to use it ('Use for research / signal context'), recommends pairing with cc.agent_strategy before live orders, and warns not to invent fills from this data alone. This provides clear usage context, an alternative tool reference, and an explicit exclusion, satisfying the criteria for explicit when/when-not.

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