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

With no annotations, the description carries the behavioral burden and does substantial work: it discloses a $0.03 USDC fee, x402 settlement, a 10-symbol cap, and the economic distinction between quoted and realizable premium. It does not mention whether data is live or cached, nor rate limits, so it is not a perfect 5, but it is far above a minimal definition.

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?

Two sentences with no filler. The conceptual distinction is front-loaded, symbol constraints appear in the middle, and cost/settlement is at the end. Every clause adds information relevant to selecting or invoking the tool.

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 tool with a single optional parameter and no output schema, the description covers the metric definitions, the two field names, symbol syntax, the symbol cap, and the cost. It does not spell out the response container or behavior when symbols are omitted, but the schema covers the default and the named fields are sufficient to interpret results.

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 already documents the symbols parameter fully, including format, default, and optionality, so the baseline is 3. The description adds the max-10 constraint and a concrete example, which improves call correctness beyond the schema alone.

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 defines the tool as returning the kimchi premium in two distinct forms, naming the exact fields and their meanings. It stops short of an explicit verb like 'returns' and does not directly compare with history/stats siblings, but the two-basis explanation makes the resource unambiguous.

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?

No explicit guidance is given for when to use this tool versus kimchi_premium_history, kimchi_premium_stats, or crypto_krw_ticker. The usage context is only implied: an agent needing the two premium rates can infer this tool is appropriate, but exclusions and alternatives are not stated.

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