Create line

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

Annotations already declare this is a non-readOnly, non-destructive, idempotent creation tool. The description adds useful behavioral context beyond annotations: cap decorates both ends, a line keeps its length while a filled rectangle stretches, and editor compatibility is given.

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 dense but front-loaded, with use cases first and geometry details following in a logical order. Every sentence earns its place, including the auto-layout alternative and editor support note.

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 create tool with no output schema and annotations covering safety and idempotency, the description gives enough to invoke the core line creation correctly. It is missing some placement and styling details, such as default parent behavior, but remains largely complete for the primary use case.

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 description explains key geometry and appearance parameters such as length, angle, cap, and the x/y origin, which adds meaning beyond the schema. However, with 12 parameters and only 50% schema description coverage, several parameters such as parentId, name, color, weight, dashPattern, and idempotencyKey are not covered or only partially covered by the description.

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?

States a specific verb and resource ('Create line') and immediately lists concrete use cases: dividers, connectors, arrows, underlines, decorative strokes. It also distinguishes the tool from figma_create_rectangle for auto-layout dividers, so an agent can tell it apart from siblings.

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 explains when to use a line versus a rectangle in auto-layout contexts, and notes editor support for Design, FigJam, and Slides. It provides clear usage context but does not explicitly exclude or compare against other nearby tools such as figma_create_connectors or figma_create_vector.

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