safe_divide

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

Discloses key behavioral traits: exact decimal arithmetic and null return on divide-by-zero. Since no annotations are provided, description carries the full burden, and this is sufficient for a simple math tool. However, it omits precision/rounding behavior implied by decimal_places parameter.

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?

Two concise sentences with no wasted words. Front-loaded with function and behavior, followed by usage guidance.

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?

Covers purpose, usage, and key behavior. Missing details on decimal_places semantics (rounding/truncation) and the return type for normal cases. Without an output schema, these gaps reduce completeness.

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?

Description does not add meaning beyond the input schema for numerator and denominator, and it completely ignores the decimal_places parameter. With 67% schema coverage, the description fails to compensate for the undocumented parameter.

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?

Description clearly states the verb 'divide' and resource 'two numbers'. It specifies 'exact Decimal arithmetic' and 'returns null on divide-by-zero', distinguishing it from other arithmetic tools like percentage_of_total.

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 states use cases: 'Use for ratios, rates, per-unit costs.' This provides clear context for when to use the tool, though it doesn't explicitly state when not to use it or list alternatives.

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