analyze_ui

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

Without annotations, the description carries the full burden of behavioral transparency. It discloses the output: 'get back which components are in the system, which colors match existing tokens (using perceptual color distance), and what gaps exist.' This adequately informs the agent about the tool's behavior, though it does not mention nondestructive nature or potential performance characteristics.

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, front-loaded with the tool's action and output, followed by a use case. Every sentence adds value without redundancy or unnecessary detail.

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 tool has no output schema and only three string parameters, the description sufficiently covers the return values: which components are in the system, matching colors, and gaps. It is complete enough for an agent to understand what to expect, though it lacks specific formatting details of the output.

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 each parameter is already documented in the input schema. The description does not add new meaning beyond the schema; it merely repeats 'components you see' and 'colors used.' The baseline of 3 is appropriate as the description provides no additional parameter context.

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 states the tool's purpose: 'Analyze UI elements and colors against the design system.' It specifies inputs (components and colors) and outputs (which match tokens, gaps). This distinguishes it from siblings like analyze_coverage or check_contrast, which serve different analysis functions.

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 clear usage context: 'Useful for reverse-engineering a screenshot or mockup into system terms.' It implies when to use this tool (when analyzing UI elements against a design system) but does not explicitly exclude cases or reference sibling alternatives. Still, the context is sufficient for an agent to decide.

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