set_item_spacing

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It simply states 'Set distance between children' without mentioning any side effects, prerequisites (beyond auto-layout frame), or special cases. This is a gap for a mutation tool; for example, it does not note that the change is applied to the node or that specific conditions (like SPACE_BETWEEN alignment) can override the value.

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, front-loaded sentence with no redundant words. It immediately conveys the tool's purpose and scope, earning a perfect score for conciseness and structure.

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?

Given the tool's simplicity, the description plus the fully self-documenting schema is largely complete. It states the target (auto-layout frame) and action. It does not explain return values, but with no output schema and a simple setter, that is acceptable. However, it could be slightly more complete by mentioning that the node must be a frame with auto-layout enabled, though this is implied by 'auto-layout frame'.

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 baseline is 3. The description adds no extra meaning about parameters; it only names the operation. The schema already documents each parameter, including notes about ignoring itemSpacing under certain conditions, so the description does not need to compensate. Thus, a 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?

The description 'Set distance between children in an auto-layout frame' uses a specific verb ('set') and resource ('distance between children' in 'auto-layout frame'), clearly distinguishing it from sibling tools like set_padding or set_axis_align. It precisely states the action and scope, making the purpose unambiguous.

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 by specifying 'in an auto-layout frame', indicating the tool is intended for auto-layout frames. It does not explicitly mention exclusions or alternatives, but the context is enough to infer when to use it, so it earns a 4.

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