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

With no annotations, the description carries the full burden. It discloses an important behavioral trait: the $0.01 USDC cost and x402 settlement mechanism. However, it does not explicitly state that this is a read-only snapshot, nor does it mention rate limits, data freshness, or error behavior.

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 two sentences with no filler. The first sentence front-loads the purpose and output categories; the second concisely covers the parameter and cost. Every sentence earns its place.

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 single-parameter snapshot tool, the description covers what it returns, the parameter bounds, and the cost. It lacks explicit output schema details, but the categories (top traded value, gainers, losers) provide reasonable expectations. Minor omissions around error behavior and freshness do not prevent correct invocation.

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%, and the schema already documents the 'limit' parameter with default and max. The description adds marginal context that the limit applies to the volume ranking, but this is largely redundant with the schema's 'top-volume markets' phrasing.

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 a snapshot of all Upbit KRW crypto markets, listing specific output categories: top by 24h traded value, top gainers, and top losers. This distinguishes it from likely single-market tools like crypto_krw_ticker, though it does not explicitly name differences.

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 purpose strongly implies usage for broad market overviews rather than individual tickers or derived metrics, but no explicit when-to-use or alternative routing is provided. Sibling tools are not referenced, leaving the agent to infer the appropriate context.

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