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

Annotations already declare readOnly, idempotent, open-world, and non-destructive. The description adds that no payment or wallet is needed, which is useful cost/auth context beyond annotations. It doesn't disclose error/rate-limit behavior, but with annotations covering safety, this is adequate.

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 three concise sentences, front-loaded with the core function, then cost and default behavior. Every sentence adds value.

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?

Given the tool's simplicity, the presence of a rich output schema, full parameter coverage, and annotations, the description covers the essential behavioral context (public API, free, defaults). No major gaps for an AI agent to correctly select and invoke this tool.

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?

Input schema covers both parameters with descriptions and defaults. The description's 'Defaults to ETH/USD' adds no new information beyond schema (symbol defaults to ethereum, vsCurrency to usd). With 100% schema coverage, the description's contribution to parameter meaning is minimal, but not incomplete.

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 clearly states the tool fetches a spot token price from CoinGecko, using a specific verb and resource. It does not explicitly compare to sibling tools like market.crypto, but the scope is well defined. Given the mention of CoinGecko and spot price, it is easy to distinguish from other network tools, though not explicitly.

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?

The description gives context that the API is public and free, and mentions default ETH/USD, which guides basic usage. However, it does not state when to prefer this tool over market.crypto or other siblings, nor any exclusions (e.g., not for historical data). Usage is implied but not explicitly detailed.

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