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

Annotations already declare destructiveHint=true and readOnlyHint=false. The description adds that it modifies appearance and applies foundational design tokens, which gives some context. However, it does not disclose potential side effects (e.g., overriding existing styles) or reversibility, so it stays at a baseline level given the annotation coverage.

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 two sentences long and front-loads the core purpose. The first sentence is a clear action statement; the second adds context about design tokens. No filler or rephrasing of the name, making it efficient and well-structured.

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?

Given the annotations (destructive profile), a 100% schema-coverage, and an output schema, the description sufficiently explains the tool's role and behavior. It could mention potential irreversibility, but that is already flagged by destructiveHint. The description is adequate for an agent to select and invoke the tool correctly.

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?

Input schema covers all three parameters with detailed descriptions, achieving 100% coverage. The description does not add parameter-level details beyond saying it applies the selected design system to chosen screens, which is already implied. Baseline 3 is appropriate when schema handles the heavy lifting.

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 first sentence clearly states the action: 'Applies a design system to a list of screens.' This distinguishes it from sibling tools like create_design_system and update_design_system, which deal with design systems themselves. The second sentence elaborates the scope (modifying appearance via design tokens), reinforcing a specific and unambiguous purpose.

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 explicitly says 'Use this tool when the user wants to update one or more screens to match the style of a design system.' This provides clear when-to-use guidance. It does not mention exclusions or alternatives, but the context is specific enough to avoid confusion with sibling tools.

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