getIndexPriceKline

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful behavioral context beyond annotations: each kline is a 5-element array, data is returned in reverse chronological order, and no authentication is required. It does not mention pagination or rate limits, but the read-only open-world annotations lower the burden.

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-organized with sections and bullets, but it repeats 'Data is returned in reverse chronological order (most recent first)' twice, and the agent hint largely duplicates the 'Do not use' guidance already provided. The structure is clear, but the redundancy means not every sentence earns its place.

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 description covers use cases, alternatives, output format, ordering, supported products, and authentication, which is substantial. However, with no output schema and six parameters at 0% schema coverage, it leaves important calling details undocumented, such as timestamp units, pagination behavior, and category-to-product mapping. It is a solid but incomplete definition for a tool of this complexity.

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 burden of explaining parameters, but it explains none of them. It does not clarify that start/end are timestamps, what units they use, how interval maps to timeframes, what category values mean, or how limit behaves. It only describes the output array format and ordering, which does not compensate for the lack of parameter documentation.

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 a specific verb and resource: 'Query historical index price klines derived from the composite spot price across multiple exchanges.' It also explicitly differentiates this endpoint from sibling tools getMarketKline, getMarkPriceKline, and getPremiumIndexPriceKline by naming exactly what this tool is not for. An agent can distinguish it without opening any schema.

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 gives explicit use cases: research/backtesting, comparing index vs mark price, and building charts of the spot price reference. It also provides explicit exclusions with named alternatives: 'Do not use this endpoint for trading price candles — use getMarketKline' and 'Do not use this endpoint for mark price candles — use getMarkPriceKline.' This is strong guidance with no ambiguity.

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