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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Calculate tips and bill splits' and does not state what output is produced (e.g., total with tip, per-person share, rounding behavior), whether inputs are required, or how invalid values are handled. For a calculation tool this is a notable gap.

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?

The description is a single short sentence with no filler. It front-loads the core purpose and earns its place; nothing is redundant or off-topic.

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?

The tool is simple, but the absence of an output schema and annotations means the description should explain return values and usage more thoroughly. It does not clarify the calculation result, rounding behavior, or how it differs from x402-tip-split, leaving an agent to guess critical invocation details.

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 coverage is 100%, so the baseline is 3. The schema parameter descriptions are generic ('Amount to process', 'People to process', 'Percent to process'), but the tool description provides context that amount likely means the bill amount, people the number of diners, and percent the tip percentage. It adds some meaning but does not specify units, formats, or constraints.

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 clear action ('Calculate') and resource ('tips and bill splits'), so an agent knows what the tool does. However, it does not distinguish it from the sibling x402-tip-split, which appears to cover an overlapping purpose, so it gets a 4 rather than 5.

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?

There is no guidance about when to use this tool versus alternatives. In particular, a closely named sibling x402-tip-split exists, but the description does not explain which one to choose or mention any exclusionary conditions. This is effectively no usage guidance.

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