core.add

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

Annotations already cover safety (readOnlyHint, idempotentHint, closed-world), so the description earns credit for adding domain behavior: computation to 50 significant digits and no separate rounding step. It does not mention limits on operand count or error behavior for malformed input, keeping it short of a 5.

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 short sentences, front-loaded with precision and return form, then constraints, then the usage directive. Every sentence carries information, though the trace_level sentence is slightly abrupt and could tie more clearly to output behavior.

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?

An output schema exists, so return-value detail is not required from the description, and the description still names the result string and precision. For a two-parameter arithmetic primitive with read-only annotations, nothing essential is missing.

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 must carry the load, and it largely does: operands are described as a list of numeric strings without commas, units, or spaces, and trace_level is given its three values with 'summary' marked as the default. It stops short of stating what full vs none actually change in the output, so not a 5.

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 ('Decimal 정밀 덧셈') and adds the output form ('합을 result 문자열로 반환'). An agent can distinguish it from core.sub/core.mul/core.div purely from the name plus this sentence.

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?

Explicitly directs the agent to use the tool rather than doing mental arithmetic ('합계를 직접 암산하지 말고 이 도구로 구한다'), which is real usage guidance. It does not name alternatives such as core.calc or core.batch, so the sibling-routing guidance is implied rather than stated.

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