crypto.gcd

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

Annotations already declare readOnly/idempotent/closed-world, and the description adds real behavioral detail beyond them: sign is ignored, a 2048-digit limit applies, both-zero returns 0, and decimal points or commas are rejected. It leaves minor behavior implicit, such as whether the result is always non-negative.

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 dense sentences with no filler, and the core operation plus input contract are front-loaded ahead of edge cases and chaining advice. The final sentence bundles two ideas (rejection rules and multi-number chaining) but stays compact.

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 arithmetic tool with an output schema already documenting the return, the description covers everything an agent needs: input encoding, limits, rejection rules, the degenerate zero case, and how to extend beyond two operands.

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?

With 0% schema description coverage, the description carries the full burden and does so: it explains that a and b are integer-encoded strings, that signs are dropped, that the digit limit is 2048, and what input shapes are rejected. Only the exact output encoding of edge cases beyond both-zero is unspecified.

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 and resource ('두 정수의 최대공약수(GCD)를 구한다') so the operation is unambiguous. It does not distinguish itself from nearby siblings such as crypto.lcm or crypto.egcd, so an agent must infer the boundary from names alone.

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?

Gives concrete usage direction: exactly two operands, and for three or more numbers the caller must chain by re-feeding the result. It does not state when to prefer crypto.egcd or crypto.lcm, so it is clear context without explicit exclusions.

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