design_add_guide

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

No annotations are provided, so the description carries the full disclosure burden, and it says nothing about scope (target sketch/layer), whether the guide layer is visible or locked by default, or whether it can be removed afterward. It does list the type enum, but that is already in the schema, so it adds no behavioral context.

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, front-loaded with the action and immediately followed by the type options. The type enumeration duplicates the schema enum, which is mildly wasteful, but it is not enough to hurt readability.

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?

With no output schema needed and full schema coverage, the description covers the core action and valid types adequately. The remaining gap is the absence of any note on which guide-type-specific parameters apply (rows/columns/margin only for grid, pattern only for diagonal), which the schema implies but never states outright.

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 every parameter including rows, columns, margin, pattern, and guideColor is already documented with defaults. The description's type list merely repeats the schema enum, so the baseline 3 applies.

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 ('Add a layout guide layer') and enumerates the four supported guide types, so an agent knows exactly what gets created. It does not, however, distinguish itself from nearby siblings like design_add_custom_guide, design_add_composition_guide, or design_add_proportion_grid, which an agent could easily confuse it with.

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 offers no when-to-use or when-not-to-use guidance, no prerequisites, and never names an alternative. With design_add_custom_guide sitting right beside it, the absence of any routing hint leaves the agent to guess which guide tool applies.

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