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

The description provides key behavioral traits beyond the schema: it is a paid tool ($0.001 per call via x402), uses an aggregated feed with per-coin confidence score, and has ~15s freshness. No annotations are provided, so the description fully carries this burden and does so thoroughly.

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 concise (3 sentences) and front-loaded with the core purpose. Every sentence adds value: accepted formats, feed characteristics, pricing. No waste, well-structured.

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 no output schema, the description covers return values (confidence score, freshness), pricing, and input formats. It is complete for the complexity of a crypto price tool. No gaps in critical information.

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 schema covers 100% of parameters, and the description adds significant meaning: it explains accepted formats (major symbols, coingecko:<id>, <chain>:<tokenAddress>), maxItems of 50, and example inputs. This enriches understanding beyond the schema's basic description.

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 provides real-time USD spot prices for crypto assets. It specifies multiple accepted symbol formats (major symbols, CoinGecko IDs, chain:address), distinguishing it from sibling tools like defi_tvl or gas_prices which serve different purposes.

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 explicitly says when to use this tool: for real-time USD spot prices of crypto assets. It mentions aggregated feed with confidence score and freshness, and pricing details. Sibling tools are clearly different, so no confusion about when to use alternatives.

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