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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the trailing "Read-only" adds no information. The description does contribute the ETH-denomination and "recent" window framing, but says nothing about how the interval/limit defaults shape the returned window.

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?

Three short, front-loaded clauses with no filler; the resource and unit come first and the usage hint follows. The closing "Read-only" is wasted words given the annotation already states it.

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?

With no output schema and zero parameter documentation, the description should explain candle shape and how limit/interval interact, but it does neither. An agent can call it, but cannot predict the returned data window or field structure.

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 must carry the parameter burden and does not. It never explains limit (default 24, max 200), the interval enum's units (seconds: 60/300/900/3600/86400), or the token pattern constraint; only the denomination is clarified.

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?

States a specific resource (OHLC candles for a token) and the unit of denomination (ETH per token), which is meaningful and unambiguous. It does not explicitly differentiate itself from siblings like get_prices, so it falls short of 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 phrase "Use for 'how has X moved today'" gives one concrete usage scenario, which is more than nothing. However, it offers no exclusions or named alternatives (e.g., when to prefer get_prices for spot data), leaving the agent to infer routing.

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