set_fill_color

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

With no annotations, the description carries full burden but provides minimal behavioral context. It states the tool modifies a node (implying mutation) but doesn't disclose permissions needed, whether changes are reversible, rate limits, or what happens if the node doesn't exist. The description doesn't contradict annotations (none provided), but offers insufficient transparency 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, efficient sentence that directly states the tool's purpose. It's appropriately sized for a straightforward tool, though it could be slightly more front-loaded by specifying the color format (RGBA) earlier.

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 mutation tool with no annotations and no output schema, the description is incomplete. It doesn't explain what the tool returns, error conditions, or important behavioral aspects like whether it affects all fills or just the primary fill. The high schema coverage helps, but critical context for safe invocation is missing.

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%, providing clear documentation for all parameters (nodeId, r, g, b, a). The description adds no parameter-specific information beyond implying the tool applies to nodes, which is already covered by the schema. Baseline score of 3 is appropriate as 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 action ('Set the fill color') and target resource ('a node in Figma'), specifying applicable node types ('TextNode or FrameNode'). It distinguishes from sibling tools like 'set_stroke_color' by focusing on fill color, but doesn't explicitly contrast with other color or node modification tools.

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?

No guidance is provided on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing a valid nodeId), compare with similar tools like 'set_stroke_color', or indicate when other tools might be more appropriate for color changes.

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