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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds essentially nothing beyond that — no note on whether the result is cached, whether unsupported currencies error or return empty, or what determines a 'supported' chain.

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; the resource and its filter are stated in the first few words. Nothing wastes the agent's context.

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?

For a one-parameter read-only tool with full schema coverage and no output schema, the definition is minimally sufficient. It nevertheless leaves open what a returned 'chain' actually is (network name, chain ID, withdrawal-enable flag), which an agent may need to know before chaining calls.

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% and the single 'currency' parameter already carries a description with examples (BTC, USDT). The description does not add format constraints (symbol vs. full name vs. contract address) beyond what the schema provides, so the baseline 3 is appropriate.

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 ('List chains supported for a currency'), so an agent immediately knows this returns blockchain networks for a given asset. It does not explicitly differentiate itself from sibling currency-listing tools such as cex_spot_list_currencies or cex_unified_list_unified_currencies, but the 'chains' resource is distinctive enough to avoid confusion.

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 when-to-use guidance, no exclusions, and no mention of alternative tools. The agent must infer that this is a lightweight lookup tool called before a deposit/withdrawal flow, which is not stated anywhere in the description.

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