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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, covering the safety profile. The description adds only the 'TradFi symbol' scope and otherwise no behavioral context such as pagination, rate limits, symbol universe restrictions, or default time 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?

A single, front-loaded sentence with no filler or redundancy. It is efficient but so terse that it leaves no room for context, which is why it lands at 4 rather than 5.

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?

There is no output schema, so the description could reasonably state what OHLCV fields are returned or how limit/time-range pagination behaves, but it does neither. For a simple annotated read query the annotations carry safety, but the return-shape gap leaves it only minimally adequate.

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%, with every parameter documented and kline_type carrying an explicit enum, so the schema does the heavy lifting. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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 verb (Get) and resource (kline/OHLCV data) scoped to a TradFi symbol, which separates it from cex_cfd_query_symbols (listing) and cex_cfd_query_symbol_ticker. However, it does not distinguish itself from the many other candlestick tools in the catalog (cex_fx_get_fx_candlesticks, cex_dc_list_dc_candlesticks, cex_spot_get_spot_candlesticks).

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?

No when-to-use guidance, no prerequisites, and no named alternatives despite several sibling kline/ticker tools existing in the same CFD namespace and across other markets. The agent must infer usage entirely from the tool name and description.

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