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

Annotations already disclose write semantics (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so safety is covered externally. The description adds the behavioral fact that preset drives sizing and overrides explicit dimensions, but says nothing about which project/artboard it lands in, defaults for name or position, or what it returns.

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 with the core action first and the sibling exclusion second — zero padding. The parenthetical '(preset sizes it)' is terse to the point of being slightly cryptic about precedence over width/height.

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 9-parameter creation tool with no required params and no output schema, the description omits critical call-time context: default naming, default placement, background visibility behavior, and the target project. An agent could call it but would be guessing on most parameters.

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 22% (only tone and preset documented), so the description must carry the rest and largely doesn't. It clarifies the preset-versus-width/height relationship, which is genuinely helpful, but leaves x, y, name, background, and show_background entirely unexplained, including what happens when position is omitted.

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 ('Add') and enumerates the resource in user-facing terms (screen, slide, page, post), which maps onto 'artboard'. It also clarifies that presets supply dimensions in place of width/height. The only gap is that it never literally says 'artboard', leaning on the tool name to bridge that.

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?

It explicitly excludes a nearby sibling: anything a control opens (dropdown, filter, menu) belongs to add_hidden_ui, not here. That is a real routing rule. But it doesn't say when to use this versus set_artboard or create_layout, so the guidance is useful but not complete.

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