core.div

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

Goes well beyond the readOnly/idempotent annotations by disclosing the b=0 error path, the 50-significant-digit precision ceiling, and the truncation (not rounding) behavior when the division is not exact. Missing is anything about output shape or the role of trace_level, but the core behavioral risks are covered.

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?

Four tight sentences, front-loaded with the operation and then the input-format constraint, error condition, and precision limit in order of importance. Every sentence adds information; only the final rounding note is slightly tangential but still useful.

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?

With an output schema present, the description need not explain return values, and it supplies the precision semantics an agent needs to interpret the result. The unaddressed trace_level parameter is the one real gap for a three-parameter tool.

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 0%, so the description carries the full burden. It compensates well for a and b (numeric strings, no commas/units/spaces), but the third parameter trace_level is never mentioned anywhere, leaving one parameter completely undocumented.

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 ('Decimal 정밀 나눗셈 a / b') and immediately scopes it as arbitrary-precision division rather than the integer/normal arithmetic done by siblings like core.add or core.mul. An agent can tell exactly what operation this performs without opening the schema.

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?

Provides clear operational context: the inputs must be bare numeric strings, and if an integer quotient or won-unit truncation is wanted the result must be rounded separately. It does not name sibling tools such as core.calc or core.mul or state explicit exclusions, so it falls short of a 5.

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