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

With no annotations provided, the description carries the full behavioral disclosure burden. It transparently reveals the most important non-obvious behavior: the call costs $0.005 USDC via x402 on Solana mainnet. It also clarifies the interval cap. It does not mention failure modes or prerequisites, but the paid external-call behavior is clearly flagged.

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 two tight sentences: the first delivers the core function and output metrics, the second delivers cost and payment rail. There is no filler, and the key information is front-loaded.

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 low-complexity tool with two parameters and no output schema, the description covers the essential output fields, scope, and cost. It could be more complete with explicit return shape or sibling routing, but nothing critical is missing for correct invocation.

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 description coverage is 100%, so the schema already documents symbol and limit with format, range, and default. The description mostly restates these constraints ('any USDT perp', 'up to 200 intervals') and adds output context rather than new input semantics, which lands at the baseline 3.

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: 'Funding-rate history for any USDT perp', and lists the concrete output metrics (average, annualized, share of positive intervals). This clearly distinguishes it from funding-related siblings like get_funding_rate or get_funding_extremes by emphasizing historical calculation rather than current rate or extremes.

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 phrase 'what the carry has actually been' gives a clear use case: historical funding performance for a USDT perpetual. It does not explicitly name alternatives or exclusion conditions, but the context is clear enough that an agent can infer when this tool is appropriate.

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