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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context that annotations don't provide: it returns an estimate along with the source and page URL, and cites the legal basis (소득세법 제59조의4, 2025 tax amendment). This is valuable given there is no output schema.

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?

Three short sentences that are front-loaded with the tool's identity. The Korean title duplicates the tool name slightly, but otherwise every sentence (source URL, legal reference, return behavior) carries information. No filler.

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 two-parameter read-only calculator with no output schema, the description covers the essentials: what it computes, the legal basis, and a note on the return value (estimate plus source/page URL). It could say more about how items kinds map to credit rates, but the schema already enumerates the kinds.

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 description coverage is 100%, so the schema already documents both 'items' (including the kind:spend format) and 'decided_tax' (the credit cap). The description adds no parameter-level meaning beyond what the schema provides, so the baseline 3 applies.

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 names the specific resource (Korean education expense tax credit, 2026 spending) and states that it returns an estimate, so an agent can tell it computes a value. However, it never distinguishes itself from the closely related korea_tax_refund sibling, so the purpose is clear but not sibling-differentiated.

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?

There is no when-to-use or when-not-to-use guidance. The description does not mention the overlapping korea_tax_refund tool, nor does it explain when a user should route here versus that sibling. The only contextual hint is the '2026 spending' qualifier.

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