Plan a settle-up

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

The annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond that: it computes a minimal payment set, checks against Splitwise's simplified debts, and explicitly states there are no external effects such as moving money or recording payments.

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 deliver the core purpose, output nature, and key negative side effects. Every sentence earns its place, and the primary action is front-loaded.

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?

With one simple required parameter, rich annotations, and an output schema present, the description covers everything an agent needs to invoke the tool correctly. It explains the computation, the reference behavior, and the absence of side effects.

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 schema has 0% description coverage, and the description does not explicitly explain group_id. However, the single parameter is self-descriptive from its name and type, and the description says 'closes out a group,' which makes the intended parameter usage reasonably inferable.

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 uses a specific verb and resource: 'Compute the minimum set of payments that closes out a group, with who pays whom.' It also clearly distinguishes itself from execution-focused siblings by saying it does not move money or record payments, so an agent can tell it is a planning/calculation tool.

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 description clearly implies when it should be used: for calculating a settlement plan rather than executing one. The explicit statement that it does not move money or record payments separates it from settle_up in context, though it does not name alternative tools or explicit conditions.

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