Figma MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states the tool 'Get a thumbnail,' implying a read-only operation, but doesn't clarify aspects like whether it requires authentication, has rate limits, returns image data or a URL, or handles errors. This leaves significant gaps in understanding the tool's behavior beyond its basic function.

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 a single, clear sentence that efficiently conveys the tool's purpose without unnecessary words. It is front-loaded with the core action and resource, making it easy to parse. Every part of the sentence contributes directly to understanding the tool's function.

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 lack of annotations and output schema, the description is incomplete for a tool that retrieves visual data. It doesn't explain what a 'thumbnail' entails (e.g., image format, size, or how it's returned), which is critical for an AI agent to use the tool effectively. The schema covers inputs well, but the output behavior remains undocumented.

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?

The input schema has 100% description coverage, clearly documenting both parameters (file_key and node_id) with their purposes and formats. The description adds no additional semantic information beyond what the schema provides, such as examples or edge cases. This meets the baseline score since the schema adequately covers parameter details.

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 action ('Get a thumbnail') and the target resource ('a specific node in a Figma file'), making the purpose understandable. However, it doesn't differentiate this tool from potential sibling tools that might also retrieve node information or thumbnails, as the sibling list includes file management and comment tools but no direct alternatives for viewing nodes.

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 no guidance on when to use this tool versus alternatives. It doesn't mention any prerequisites, such as needing the file key and node ID, or specify scenarios where this tool is appropriate over other methods for accessing node data. This lack of contextual direction limits its utility for an AI agent.

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