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

Annotations already indicate readOnly and openWorld, but the description adds significant behavioral details beyond them: exact thresholds (1-minute, >1%), the focus on volume spikes and top 20 tokens, and crucially, the monetization (cost per call, payment methods, required x402 SDK). This goes well beyond what annotations provide, with no contradiction.

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 functionality is front-loaded in the first sentence and the following two sentences add useful context. However, the payment metadata (4 lines with emojis) is somewhat verbose and could potentially be condensed or moved to a separate metadata field, though it is structured and informative.

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 no-param read-only tool with an output schema, the description is comprehensive: it specifies the exchange (Upbit), time window (1-minute), criteria (>1%, volume spikes, top 20), and the monetization model. It fully equips 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?

The tool has 0 parameters, and the schema coverage is trivially 100%. Per rubric, baseline is 4 for 0-param tools. The description correctly adds no parameter information; it's unnecessary.

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's purpose: 'Get Korean market movers' with precise criteria (1-minute price surges/crashes >1%, volume spikes, top 20 tokens by trading volume on Upbit). This specific verb+resource+metric set distinguishes it from sibling tools like get_kr_prices or get_kimchi_premium.

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 provides clear context: 'Korean retail activity often leads global price movements — early signal for traders.' This implies when to use the tool (for early trading signals) but does not explicitly mention alternatives or when not to use it, preventing a 5.

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