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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the description need not restate safety. It adds that data is 'current' and sourced from CoinGecko, but does not disclose behaviors like rate limits, response format, or handling of invalid coin IDs. This is minimal extra context beyond annotations.

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?

The description is compact and front-loaded with the purpose, followed by a concise, well-structured Args section. Every sentence earns its place; no filler or redundant phrasing.

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 read-only tool with two parameters and no output schema, the description covers the core purpose and parameters. It does not specify return fields or error behavior, but the purpose is clear enough for the agent to invoke it successfully. Completeness is strong but not maximal.

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?

The description's Args section fully explains both parameters: coins as a list of coin IDs with empty list meaning top coins, and max_results with a default of 50. Since schema description coverage is 0%, the description carries the entire semantic burden for both parameters.

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 'Get current cryptocurrency prices and market data from CoinGecko' uses a specific verb (get) and resource (cryptocurrency prices/market data), and the source (CoinGecko) clearly distinguishes it from sibling tool exchange_rates. It is not a tautology and fully states what the tool does.

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?

Usage is implied (e.g., use when you need crypto prices), but the description does not explicitly contrast with exchange_rates or provide when-to-use/when-not-to-use guidance. No exclusions or alternative recommendations are mentioned.

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