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

With no annotations, the description carries the load and does disclose the pay-per-call cost ($0.01 USDC) and the exact return fields (price, 24h change, quote volume), which are real behavioral facts beyond the schema. It omits error behavior for invalid/unlisted symbols and the endpoint's rate or auth characteristics.

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?

One dense sentence front-loads the core action and scope, then tacks on the return fields, endpoint, and price. No filler sentences.

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 tool with no output schema, the description covers input format, returned fields, and cost. Only edge-case behavior (invalid symbols, partial failures) is left unstated.

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% and the single parameter is fully documented there, including the <=25 limit. The description's comma-separated example (btc,eth,sol,doge) reinforces the format but adds nothing the schema lacks.

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+scope: 'Batch spot prices for MANY coins in ONE call,' and enumerates the returned fields. It clearly separates itself from the single-coin crypto_price sibling via the batching emphasis.

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?

'MANY coins in ONE call' with a comma-separated list strongly implies when to use this over the singular price tool, and the pay-per-call note flags that each invocation costs money. It stops short of explicitly naming crypto_price as the single-coin alternative.

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