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

With no annotations provided, the description carries the full behavioral burden, and it delivers: it discloses cost (free), rate limiting (30 requests/min), scope (BTC only), and even that the response lists what the sample withholds. This goes well beyond the tool name and prepares the agent for what the call returns and what it omits.

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?

Three sentences deliver the core purpose first ('FREE SAMPLE, no payment'), then the rate limit, then the paid alternative and response behavior. There is no filler, and every sentence earns its place. The structure is efficient and 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 zero-parameter tool with no annotations and no output schema, the description covers purpose, cost, rate limit, the paid alternative, and the response's withholding behavior. It is nearly complete for correct invocation, though it does not specify the exact response format or units of the funding rate. These are minor for a free sample with no inputs.

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 tool has zero parameters, so there are no parameter semantics to clarify. The description implicitly confirms that no inputs are required by framing the call as a simple sample. A score of 4 reflects the baseline expected for a no-parameter tool.

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 'FREE SAMPLE, no payment: the BTC perpetual funding rate,' clearly identifying both the resource and the tool's sample scope. It also distinguishes itself from the paid sibling get_funding_rates by explicitly noting the paid version covers every tracked perpetual. An agent can immediately tell what this tool does and how it differs from nearby alternatives.

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 positions this tool as the free sample and points to the paid get_funding_rates as the option for broader perpetual coverage. It also states the 30 requests/min rate limit, giving a concrete constraint on when use is appropriate. This effectively routes the agent between siblings without leaving the decision to inference.

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