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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower. The description still adds genuinely useful information beyond them: the per-call cost ('0.1 points per call') and the 120-coin batch ceiling, which an agent must know for budgeting and batching. It says nothing about the response shape, though no output schema exists to carry that.

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?

Two short fragments, front-loaded with the capability ('Latest prices for up to 120 coins') and trailed by the cost note. Every word earns its place; there is no filler or redundancy.

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 quote tool with no output schema and no nesting, this is adequate but leaves gaps: the description never hints at what a quote contains (price, timestamp, change) or how unknown/too-many symbols are handled. An agent can call it correctly but cannot anticipate the return payload.

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 there is a single parameter, so baseline would be 3. The description adds a real constraint not present in the schema — the 120-symbol cap on the symbols list — which is meaningful for how an agent chunks its requests.

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+resource ('Latest prices') and a clear scope bound ('up to 120 coins'), so an agent knows exactly what comes back. It does not, however, differentiate itself from siblings like get_crypto_candles or get_crypto_indicators, which also return crypto price 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?

'Latest prices' implies a real-time snapshot rather than historical series, which lets an agent infer this is the right tool for current quotes. But there is no explicit when-to-use, when-not-to-use, or named alternative such as get_crypto_candles for time-series data, so the guidance remains implied.

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