set_fill_color

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

With no annotations, description adds behavior about alpha defaulting to 1 and use of alpha 0 for transparency. However, it does not disclose other behavioral traits like whether the tool replaces existing fills or if it requires certain permissions.

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 concise sentences. First sentence states purpose directly, second adds critical detail about alpha behavior. No unnecessary words.

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 simple color-filling tool, the description covers the essential purpose and alpha behavior. However, it does not explain whether the fill replaces existing ones, or that it sets a solid color (not gradient), which could affect usage. Lacks guidance on return values or side effects.

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 coverage is 100%, so baseline is 3. Description slightly adds value by explaining the alpha default in plain language and suggesting use of alpha 0, but this is already implied in the schema description of the alpha parameter.

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?

Description clearly states 'Set the fill color of a node in Figma' with a specific verb and resource. It differentiates from sibling tools like set_stroke_color by focusing specifically on fill color.

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?

Implies usage through schema requirements and alpha behavior, but provides no explicit guidance on when to use this tool over alternatives or any prerequisites. Does not mention exclusions.

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