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

Annotations already declare readOnlyHint and openWorldHint. The description meaningfully adds that the tool is paid ($0.002 per call) and requires a micropayment client, which is essential behavioral context for an agent deciding whether to invoke it. It also clarifies return fields.

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 core purpose is front-loaded in the first sentence, followed by a structured payment section and clear argument list. Although it includes emojis and a docs link, each section earns its place; nothing is redundant.

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 output schema and annotations exist, the description covers purpose, payment requirements, argument semantics, and return fields. For a paid price-query tool with two optional parameters, this is complete and actionable.

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 descriptions cover both parameters, so baseline is 3. The description adds extra value with example symbols (SOL, DOGE) and explicitly explains the 'all' option for exchange, going beyond the schema's brief descriptions.

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 uses the specific verb 'Get' and identifies the resource as 'cryptocurrency prices from Korean exchanges (Upbit, Bithumb)', while also listing the returned data (KRW prices, 24h volume, change rate). This clearly distinguishes it from siblings like get_kimchi_premium or get_arbitrage_scanner.

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 implies usage context by naming the target exchanges and the type of data returned, but it does not explicitly state when to avoid this tool or mention alternatives. It provides clear context without exclusions.

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