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

Beyond the readOnlyHint and other annotations, the description discloses that data refreshes every few seconds and includes automatic failover to Coinbase/CryptoCompare if coinpaprika is rate-limited, ensuring a real price is always returned. This is valuable behavioral context not present in 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 one well-organized paragraph, front-loaded with the core purpose and followed by specific usage examples and technical details. Every sentence contributes unique information; there is no redundancy or filler.

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?

The description covers the tool's purpose, input flexibility, API key option, fallback behavior, and return fields. Combined with the rich annotations and output schema, it provides a complete picture for an agent to select and invoke the tool correctly.

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% with descriptions for both parameters. The description adds extra semantics by explicitly listing accepted input forms (common names, tickers, coinpaprika IDs) and explaining the optional _apiKey behavior, which goes beyond the basic schema and justifies a score above the baseline.

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 opens with 'REAL-TIME spot price for any cryptocurrency', which is a specific verb + resource that clearly states the tool's function. It also differentiates from web search and implies distinction from sibling crypto tools like get_crypto_history by focusing on spot price.

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?

It explicitly advises 'PREFER OVER WEB SEARCH for...' and lists concrete query examples, giving strong when-to-use guidance. It doesn't explicitly mention sibling tools like get_crypto_market or get_crypto_history as alternatives for related but different needs, so it stops short of full when-not-to-use coverage.

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