getFeeRate

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

Annotations already declare readOnlyHint and openWorldHint, so the description does not need to explain safety. It adds valuable behavioral context beyond the annotations: the rate limit ('Rate limit: 10 req/s') and the return format ('Fee rates are returned as decimal strings (e.g., "0.0006" = 0.06%)'). This gives the agent concrete expectations for calling and interpreting results.

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 well-structured with a purpose sentence, a rate-limit note, and an 'Agent hint' section. It is mostly efficient, though there is some redundancy: 'Can filter by symbol (spot/linear/inverse) or baseCoin (options only)' is repeated with slightly different wording later in the hint. Still, it is compact 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?

Given the lack of an output schema, the description wisely explains the return representation and gives a usage example. It covers required parameters, filter semantics, rate limit, and returns. It does not specify the exact JSON response structure or error behavior, but for a simple read-only fee query with annotations covering safety, it is reasonably 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?

Schema description coverage is 0%, so the description carries the full burden of explaining parameters. It does so explicitly: category is required, symbol is for spot/linear/inverse, baseCoin is for options only, with concrete examples (BTC, ETH, SOL). It even explains the return value format. Every parameter is given meaningful context beyond the raw schema.

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 function: 'Query the maker and taker fee rates for the specified product category.' It names the specific resource (fee rates) and the filtering dimensions (symbol, baseCoin), making it easy to distinguish from most siblings. However, it does not explicitly reference or differentiate from a nearby sibling like getFeeGroupInfo, so it stays at a 4 rather than a 5.

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 agent hint provides a concrete usage scenario: 'Use this to check fee rates before trading.' It also gives clear per-category guidance: 'Use symbol to filter for spot/linear/inverse. Use baseCoin for options,' and notes that category is required. It does not name alternatives or when-not-to-use conditions, but the context is sufficient for an agent to decide.

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