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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the 'public' nature and the exact ISO-8601 time requirement, which is complementary context. It does not mention rate limits or pagination, but these are minor given the annotations and output schema. Moderate additional value beyond 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?

A single, dense sentence that leads with the core action and resource, then adds the crucial time-window constraint. No redundant words or filler; it is optimally concise 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 a simple read-only tool with an output schema present and annotations covering safety, the description adequately conveys the tool's purpose and input requirements. It does not mention maximum time ranges or response structure, but those are typically derivable from the output schema. The description is sufficient for an agent to invoke the tool correctly for historical candle retrieval.

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 only 25%, with only 'symbol' documented. The description adds the ISO-8601 format hint for startAt and endAt, which is useful and not present in the schema field descriptions. It does not explain the 'type' parameter beyond the enum, nor clarify relationships like startAt must precede endAt. It partially compensates for the low coverage but could be more explicit.

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 states the specific action 'Get', the resource 'public OHLCV candles', and the scoping constraint 'exact ISO-8601 time window'. It clearly distinguishes from sibling tools like orderbook or tickers by specifying 'candles', which is a unique resource among the listed siblings.

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 a temporal scoping detail but offers no guidance on when to use this tool versus alternatives, nor any exclusions or complementary usage. An agent must infer it is for historical price data from 'candles' and 'time window', but there is no explicit comparison or contextual trigger.

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