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

With no annotations, the description carries the full behavioral burden, and it adequately discloses that this is market data only, what fields are returned, and that the call costs $0.30 in USDC on Base via x402. It does not mention rate limits, data freshness guarantees, or error behavior, but the core behavioral profile is well covered for a read-only snapshot.

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 and return fields, followed by a compact payment note. Every sentence earns its place with no redundant or vague phrasing.

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 one-parameter market data tool with no output schema, the description sufficiently explains the returned fields and the venues queried. Minor gaps remain around response structure and missing-data behavior, but the definition is largely complete 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?

The only parameter, 'coin', is fully documented in the schema with an example ('string, e.g. SOL'), and the description reinforces that it takes a coin. Because schema coverage is 100%, the baseline is 3 and the description adds little beyond the schema here.

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 identifies the resource as perpetual funding for a given coin across four named venues: bitget, gate, kucoin, and okx. It lists returned fields (rate, interval, annualized, mark/index basis, cross-venue spread), but it does not explicitly differentiate itself from any sibling tool.

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 'Market data only' signals that this is a read-only data lookup rather than a trading or execution tool. However, it provides no explicit guidance on when to use this versus alternatives, and no exclusions or prerequisites beyond the payment note.

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