set_image_fill

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

The description discloses a key behavioral trait: it 'replaces the node's existing fills', which is important for a mutating tool. However, with no annotations to carry the safety burden, it does not explain whether the change is reversible, how errors are surfaced, or the destructive nature beyond that phrase.

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, well-structured sentence that front-loads the main action and then lists the supported input forms and the key side effect. There is no redundant or filler content.

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?

The core operation is clear, and the schema covers parameter details, but the description omits important invocation context such as 'provide exactly one image source' and what happens on success or failure. With no output schema or annotations, this leaves some ambiguity for an agent selecting arguments.

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%, so the schema already documents all five parameters and the enum. The description adds a high-level mapping to the three image-source parameters but does not clarify mutual exclusivity or precedence among imagePath, imageUrl, and imageBase64.

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 a specific action and resource: 'Fill a node in Figma with an image', and it lists the three supported image source kinds. It is easy to distinguish from color-fill tools like set_fill_color, though it does not explicitly name any sibling alternative.

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 the tool is for image fills, but it gives no explicit guidance about when to prefer it over set_fill_color or other fill/modification tools. It also does not state exclusions or prerequisites, such as the need to provide only one image source.

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