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

The annotations already convey readOnly, idempotent, and non-destructive behavior. The description adds the useful mental model of mixing systems but not additional behavioral detail such as output shape, invalid pair handling, or system ID lookup behavior. No contradiction with annotations.

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 short and front-loaded: one sentence defines the purpose and one sentence provides a clarifying example. No redundancy or decorative wording.

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 full input schema coverage, robust annotations, and a clear format enum, the description is complete enough for an agent to select and invoke the tool. It could be marginally stronger by explicitly noting the output is a token composition or bundle, but nothing critical is missing.

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 schema already documents the compositions array, system IDs, groups, and format enum. The description's example adds value by mapping a concrete use case to the parameter model: 'Linear's colors + Stripe's typography' translates directly to compositions pairs. It doesn't describe format further, but the schema already does.

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 action ('Mix tokens from different design systems') and a concrete result ('create a custom composite'). The example 'Linear's colors + Stripe's typography' makes the resource and scope immediately clear, and distinguishes it from sibling tools like get_design_system or generate_design_system.

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 gives clear context for when to use this tool: when combining tokens across independent design systems. It does not explicitly name alternatives or state when not to use it, but the combination-focused purpose is unambiguous enough for selection.

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