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

Annotations already cover readOnly, idempotent, openWorld, and non-destructive behavior, so the description does not need to repeat those. It adds useful context by identifying the exchange (OKX) and timeframe (current), but it does not disclose behaviors like staleness, settlement-time interpretation, or any API limitations.

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 entire description is one dense sentence with no filler. It front-loads the main object and result fields while adding a concrete example. Every phrase contributes to selecting and invoking the tool.

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 tool has a single parameter and an output schema, so the description does not need to spell out return structure. It supplies the name of the exchange, the instrument type, and the output categories. It is slightly thin on when to use it or how the 'current' rate interacts with settlement timing, but given annotations and output schema, it is largely complete.

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?

With zero schema-level description coverage, the description must clarify the instId parameter. It does so by labeling the required parameter as a SWAP instrument and giving the exact expected format ('BTC-USDT-SWAP'), which is essential since the raw schema only names it as a string. This sufficiently compensates for the missing schema text.

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 (OKX perpetual swap funding rate) and the specific kind of instrument ('SWAP' with example 'BTC-USDT-SWAP'), while also stating the key output fields ('funding rate, next settlement time, and method'). It is distinct from the history-focused sibling tool by emphasizing 'current.'

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 conveys that this is the current-rate snapshot and requires a SWAP instrument, which implies use cases. However, it does not explicitly mention when to prefer funding_rate_history or other market-data siblings, nor any exclusion criteria such as spot instruments.

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