screen.create

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

With no annotations provided, the description carries the full burden. It discloses that screens can be resized taller if content overflows, which is useful behavioral context. However, it doesn't mention important aspects like whether this operation requires specific permissions, what happens on duplicate names, or what the response looks like (no output schema).

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 appropriately sized with three focused paragraphs. The first states the purpose, the second explains parameter context, and the third provides a helpful tip. However, the tip paragraph could be more concise, and the structure isn't perfectly front-loaded with the most critical information.

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 creation tool with no annotations and no output schema, the description provides adequate context about what the tool does and parameter usage. However, it lacks information about what happens after creation (return values, error conditions) and doesn't fully address behavioral aspects like permissions or side effects, leaving some gaps given the tool's complexity.

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 5 parameters thoroughly. The description adds some value by explaining device presets with examples and clarifying that 'custom' requires explicit dimensions, but doesn't provide significant additional semantics beyond what's in the schema descriptions.

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 specific action ('Create a new screen') and resource ('in the Designer'), with additional context about what a screen represents ('page/artboard'). It distinguishes from sibling tools like screen.update, screen.delete, and screen.duplicate by focusing exclusively on creation.

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 provides clear context about when to use this tool (for creating screens with device presets or custom dimensions) and includes a helpful tip about using layout.analyze afterward. However, it doesn't explicitly state when NOT to use it or mention specific alternatives among siblings like screen.duplicate.

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