subtract

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

With no annotations, the description must carry the behavioral burden. It defines the order-sensitive subtraction behavior (a - b), which is useful. However, it does not disclose error handling, return type, or behavior for edge cases, though the schema covers input types.

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?

A single, front-loaded sentence conveys the core operation and formula without redundancy. Every word contributes to understanding the tool's purpose.

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 simple two-number arithmetic tool, the description plus schema sufficiently covers the operation and parameters. It lacks explicit return-type or error information, but the low complexity and full parameter coverage make the tool adequately specified.

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?

The input schema already provides descriptions for both parameters ('被减数' minuend and '减数' subtrahend) with 100% coverage. The description adds the explicit formula a - b, which reinforces the relational meaning of the parameters.

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 explicitly states the operation: '计算两个数的差 (a - b)', clearly indicating subtraction of b from a. This distinguishes it from sibling tools add, multiply, and divide.

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?

No guidance is provided on when to use this tool versus alternatives. The description only states the mathematical operation and does not mention exclusions, prerequisites, or when a different arithmetic tool would be appropriate.

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