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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'end-of-day' and 'price and trading volume', but does not explain the 'Light' aspect, output format, default date ranges when 'to'/'from' are omitted, or limitations compared to the FullChart sibling.

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 two sentences, front-loaded with the core action (access historical end-of-day prices) and free of redundancy. The second sentence about tracking trends is slightly generic but still conveys that volume data is included, adding some value.

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?

Key contextual information is missing. With no output schema, the description should explain the response structure but does not. More importantly, the tool name includes 'LightChart' but the description never clarifies what is 'light' compared to the full chart, which is essential for choosing between these sibling tools.

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 100%, so the input schema already documents all three parameters (symbol, from, to) with clear descriptions and examples. The tool description adds no parameter-specific semantics beyond what the schema provides, which aligns with the baseline for high coverage.

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 accesses historical end-of-day prices for cryptocurrencies, which is a specific verb+resource combination. It distinguishes from intraday crypto tools (e.g., 1Hour, 1Minute, 5Minute) but does not explicitly differentiate from the sibling getCryptocurrencyHistoricalFullChart, leaving 'Light' unclarified.

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 provides context for when to use this tool: when you need historical end-of-day cryptocurrency data to track trends. However, it does not mention alternatives or explicitly state when not to use it (e.g., for intraday data or heavier historical datasets).

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