compareFigmaToElement

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

With no annotations, the description carries the full burden of disclosing behavior. It only says 'Pixel-perfect validation' without explaining whether the tool performs a read-only comparison, requires a live page, makes network calls to Figma API, or what happens on mismatch. No side effects, auth prerequisites, or failure behavior are disclosed.

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 concise sentences with no filler. The main verb and object are front-loaded in the first sentence, and the second sentence adds context ('Pixel-perfect validation'). It is appropriately sized for a tool with clear purpose, though slightly vague tone costs a point.

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 tool has 6 parameters, no output schema, and no annotations, yet the description is minimal. It fails to explain what the tool returns (e.g., a diff percentage or pass/fail), preconditions (e.g., element must exist and be visible), or how threshold and figmaScale affect the comparison. This is a substantial gap for a tool with this complexity.

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 schema already documents all 6 parameters (fileKey, nodeId, selector, threshold, figmaScale, figmaToken) with meaningful descriptions. The tool description adds no semantic value beyond the schema, but the baseline of 3 applies because the schema does 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 description clearly states the tool's function: 'Compare Figma design with browser element' — a specific verb and both resources. 'Pixel-perfect validation' adds scope. This clearly distinguishes it from sibling tools like getFigmaFrame (retrieves frame) or screenshot (captures browser), as none perform comparison.

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 implies a validation use case but provides no explicit guidance on when to use this tool vs alternatives like getFigmaFrame, screenshot, or getComputedCss. There are no exclusions or prerequisites stated, leaving the agent to infer context from the schema alone.

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