set_fill_color

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

With no annotations available, the description carries the full burden of behavioral disclosure. It only mentions that the node can be TextNode or FrameNode, but fails to disclose what happens for other node types, whether this replaces existing fills, or how the optional alpha parameter affects behavior. This is a significant gap for a mutation tool.

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 sentence with no extraneous words, and it front-loads the action. The sentence structure is slightly awkward ('can be TextNode or FrameNode'), but it remains concise and easy to scan.

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 tool with five parameters, no annotations, and no output schema, the description is too minimal. It omits information about return values, error handling, whether the operation is destructive, and how it interacts with existing fills. The schema covers parameters but not the broader context needed for safe invocation.

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 schema provides full descriptions (100% coverage) for all five parameters, so the baseline is 3. The description adds no additional parameter meaning beyond restating 'fill color', which is already implied by the tool name.

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: 'Set the fill color of a node in Figma' and specifies the resource types it applies to ('TextNode or FrameNode'). This distinguishes it from the sibling set_stroke_color tool, which deals with stroke color instead.

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 when to use the tool: whenever you need to set the fill color on a text or frame node. However, it provides no explicit guidance on alternatives, exclusions, or when not to use it, leaving the context to be inferred.

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