design_design_add_water_ice

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

With no annotations, the description must carry the full behavioral burden; it does state the layer's content and the optional snow cover, which is real context. It omits operational traits an agent needs: that this is a mutation adding a new layer, whether it requires an open sketch/water body, and whether it is reversible.

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 tight sentences, front-loaded with the core action and followed by the preset inventory; nothing is padded. The trailing preset list is borderline filler since the enum already contains those values.

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 5-parameter mutation tool with no annotations, no output schema, and low schema coverage, the description is too thin: it says nothing about prerequisites, layer placement, or the meaning of three of the five 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 description coverage is only 40%, so the description should compensate, but it does not: seed and waterlinePosition are unexplained in both places, and the four preset names are merely repeated from the enum without describing the look of each. Only snowCover gets support ("optional snow cover").

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?

It uses a specific verb ("Add") on a concrete resource ("a frozen water surface layer") and enumerates the visual features produced (ice texture, cracks, frost, snow cover). This separates it from the liquid-water siblings such as design_add_water_surface/design_design_add_water_surface, though the description never explicitly contrasts them.

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?

There is no guidance on when to choose this over the many water-related siblings (add_water_surface, add_water_reflection, add_water_foam, set_water_conditions) or whether a scene/sketch must already exist. The preset names are listed but not explained, so nothing tells the agent which preset fits which situation.

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