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

Annotations only cover safety (readOnlyHint) and open-world scope; the description adds real value beyond them — the cost ($0.005 USDC per call), the payment mechanism (x402 on Base), and the fact that it returns the list of skipped holidays. This is meaningful operational context for a paid tool, though pagination/response format is not described.

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 compact sentences, front-loaded with the core operation, then holiday semantics, then cost. No filler and every clause carries information.

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-param date arithmetic tool with no output schema, the description covers the operation, the calendar source, the skipped-holiday return, and the payment requirement. Only the exact response shape remains unspecified, a minor gap given the tool's simplicity.

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%, so the schema already documents both params including format (YYYY-MM-DD) and negative n. The description's 'after (or before)' restates the schema's 'negative for earlier' rather than adding new meaning. 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?

States a specific verb+resource: computes 'the date N business days after (or before) a date'. It also names the holiday calendar it uses (KASI list, incl. substitute/temporary holidays), which distinguishes it from siblings like kr_business_day_check and kr_business_days_count.

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?

Usage is implied by the operation (shift a date by N business days) but the description never states when to prefer this over kr_business_day_check or kr_business_days_count. No prerequisites or exclusions are given.

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