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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description contributes by naming the metric types returned, but it does not disclose the time-series nature implied by from/limit/interval, pagination behavior, or what 'etc.' actually covers.

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 short sentence with no wasted clauses, front-loading the verb and resource. It is efficient, though the trailing 'etc.' weakens precision rather than adding information.

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 a five-parameter time-series endpoint, the description should clarify that it returns a series of statistic points and what metrics are available. The metric examples plus annotations make it minimally viable, but 'etc.' leaves the return content ambiguous.

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%, including the settle enum and interval/limit defaults, so the schema carries the parameter burden. The description adds nothing about how contract/settle scope the query or how interval interacts with limit, 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?

The description states a specific verb and resource ('Get contract statistics') and gives two concrete examples of the statistics returned (open interest, long/short ratio), so the agent knows this is a derivatives metrics endpoint. It does not distinguish itself from siblings such as cex_fx_get_fx_tickers or cex_fx_list_fx_contracts, which also return contract-level 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?

There is no guidance on when to use this tool versus the many other cex_fx_* endpoints, no prerequisites, and no mention of the required contract/settle identifiers. The agent must infer the use case from the noun phrase alone.

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