Set a slide's background color using its node ID and a hex value. Creates or updates a full-slide background rectangle.
Set the background color of a slide. Creates or updates a full-slide background rectangle.
| Name | Required | Description | Default |
|---|---|---|---|
| color | Yes | Background color as hex (e.g., '#181818') | |
| slideId | Yes | The node ID of the slide |
Changes observed during successful MCP inspections.
v1.46.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden, and it does disclose one useful behavioral fact: it creates OR updates a full-slide rectangle, implying an existing background is replaced rather than stacked. It stops short of stating whether prior background nodes are removed, whether other slide content is affected, what permissions are needed, or what is returned.
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 short sentences, zero filler, with the core action front-loaded before the implementation note. Nothing could be removed without losing meaning.
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 two-parameter mutation with full schema coverage and no output schema, the description covers the essential action but leaves open the mutation contract (what happens to an existing background, whether the change is reversible, what the call returns). With no annotations, those gaps matter more than they otherwise would.
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%: the color pattern and the slideId meaning are both documented in the schema. The description adds only the notion that the color applies to a full-slide rectangle, not extra syntax, defaults, or format detail. 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?
Names a specific verb and resource ("Set the background color of a slide") and the second sentence clarifies the mechanism (full-slide background rectangle), which distinguishes it from a generic fill operation. It does not explicitly name a sibling such as figma_set_fills, so the differentiation is implicit rather than stated.
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 on when to use this versus alternatives like figma_set_fills, figma_add_shape_to_slide, or figma_set_image_fill, nor any prerequisites (e.g., must the slide be focused or already exist). The agent must infer the selection criteria from the tool name alone.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.