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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so safety is covered. The description adds the list of valid intervals and the exchange context, but does not disclose default behavior (e.g., default interval, number of candles returned, pagination). This is acceptable but not exhaustive given the annotations.

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 short sentences, front-loaded with the main purpose. The interval list is compact and useful, and the use-case sentence is clear. No wasted words.

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 an output schema, so return values need not be described. However, the description lacks parameter semantics for 'pair' and 'since', and does not contrast with sibling market data tools. It covers the core purpose and interval options, but not enough for fully confident invocation without external knowledge.

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 compensate. It does list all valid intervals, which is helpful, but does not explain the 'pair' format (e.g., XBTUSDT vs BTC/USD) or the 'since' parameter (timestamp semantics, optionality, default). The examples in the schema hint at these, but the description adds no meaning for two of three parameters.

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 provides OHLC candles for Kraken crypto exchange pairs. It specifies the resource (Kraken pairs) and the data type (OHLC candles), and distinguishes itself from siblings like ticker, trades, and depth by focusing on charting data.

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 a clear use case: 'Use for charting Kraken pairs.' This implies when to choose this tool, but it does not explicitly mention alternatives or exclusions. A stronger statement like 'for current prices use ticker' would push it to a 5.

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