figma_export_image

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

With no annotations, the description carries the burden and does disclose meaningful behavior: compareWith triggers a headless-Chrome screenshot of the source HTML and returns both images, a diff heatmap, and the share of changed pixels. It does not cover rate limits, permissions, or the plain (non-compare) return shape, so it is useful but incomplete.

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 tight sentences with the primary action front-loaded and the compare mode second. The parenthetical about empty instances/sizes/variants is slightly padded but does convey the motivation for the visual check.

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?

For a 5-parameter tool with a nested object and no output schema, the description supplies the output content for the compare mode and the general purpose of the render. It omits what a plain (non-compare) call returns, which an agent would otherwise have to infer.

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 60%, and the description adds real meaning for compareWith (it explains what that object produces). But scale, format, and maxDimension are left entirely to the schema, and the description adds nothing about their interaction or defaults. Baseline 3 is appropriate.

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?

States a specific verb+resource: 'Render a Figma node as an image'. The stated intent ('check the result visually' after builds/edits) makes the job unambiguous. It does not explicitly distinguish itself from near-siblings like figma_verify or figma_inspect, so it falls short of a 5.

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?

Gives clear triggering context: 'use it after every build or edit to check the result visually', plus a named conditional mode (with compareWith) and what that mode adds. No explicit when-not-to-use or named alternative sibling is given, so it stops short of 5.

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