design_diff

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

With no annotations, the description carries the full burden of behavioral disclosure. It states what the tool returns (a structured diff with added, removed, style, and text changes), which is useful, but it does not clarify whether the operation is read-only, how the diff is structured, or any limitations. The mention of 'by name' is also potentially misleading given the schema uses IDs.

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 sentences with no filler. The primary action is stated first, and the use case is added in a single brief second sentence. Every part earns its place.

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 description explains the main output categories and use case, but without an output schema it does not fully specify the shape or structure of the diff. It also leaves ambiguity about the 'by name' phrasing versus the ID-based parameters, and does not address how this tool differs from the similar compare_designs sibling.

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%, so the parameters are already well documented. The description's mention of style and text changes maps to the includeStyleDiff and includeTextDiff parameters, but it does not add meaningful detail beyond what the schema already provides.

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 clearly identifies the tool's function: comparing two screens and producing a structured diff with added/removed elements, style changes, and text changes. However, it does not differentiate this tool from the sibling tool compare_designs, and the phrase 'by name' conflicts with the actual parameters, which use screen IDs.

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 provides a clear intended context: 'Useful for tracking design iterations.' It does not explicitly state when to use this tool versus compare_designs or other siblings, nor does it mention any exclusions or alternatives.

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