Top coins by market cap or volume

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

Annotations already establish the read-only, idempotent, non-destructive safety profile. The description adds meaningful context beyond that: the upstream source (CoinGecko) and the exact return composition (price, 24h change, market cap, volume, ATH distance, breadth count), which matters because no output schema exists. Rate limits and data freshness are not disclosed.

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 with no wasted clauses; the ranking scope is front-loaded and the returned fields and source follow. It opens as a noun phrase rather than an action verb, which slightly reduces scannability but does not impede understanding.

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 simple, fully-optional 3-parameter read tool with annotations covering safety but no output schema, the description adequately explains what comes back and where the data originates. Minor ambiguities remain, such as sort direction and whether the rising count is a separate field, but these are small gaps.

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 coverage is 100%, so limit, sort_by, and vs_currency are already documented. The description only adds the '24h' qualifier on volume and confirms the ranking concept, which is marginal beyond the schema — 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 names the specific resource and scope — the largest coins ranked by market cap or 24h volume — and lists the metrics returned, so it is clear what the tool produces. It does not explicitly contrast itself with siblings like get_price or get_stablecoins, leaving differentiation to the reader.

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 statement of when to use this tool versus get_price, get_derivatives, get_defi_tvl, or get_stablecoins. The sort criterion is described, but no selection guidance or exclusions are given, so an agent must infer usage from the name alone.

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