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

With no annotations, the description carries the full disclosure burden. It says nothing about return values (no output schema exists), rounding behavior, or how the split and tip are combined, so an agent cannot predict the result shape.

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 with no filler, covering both the tip and split behaviors. It is efficient, though it errs toward brevity rather than richness.

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 3-parameter tool with full schema coverage, the description is adequate to invoke it correctly. Because there is no output schema, it should ideally state what is returned (tip, total, per-person share) but does not.

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 100% and the three parameters are self-documenting with types and defaults, so the schema does the heavy lifting. The description only gestures at the same concepts (tip amount, split) without adding format or constraint detail.

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 states a specific verb (Calculate) and two concrete resources (tip amount, bill split), so the agent knows exactly what the tool produces. It does not, however, differentiate itself from nearby siblings like percentage_calculator or loan_calculator.

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?

The scenario is implicitly clear from the wording ('tip amount', 'split bill between people'), so an agent can infer when it applies. There is no explicit when-to-use, when-not, or pointer to alternatives such as percentage_calculator.

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