design_add_treeline

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

With no annotations, the description carries the full burden, and it does disclose the visual behavior well (dense canopy mass, irregular top edge, silhouette band). It does not disclose operational behavior: whether a sketch must be open, where the layer lands in the stack, whether it replaces or stacks with existing layers, or what is returned. Useful but incomplete for a mutation tool with zero annotation coverage.

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?

Four sentences, front-loaded with the core identity before the sibling distinction and preset list. Minor waste: the style families named in prose ('deciduous, conifer, palm, bare winter') overlap with the preset list that follows, so a small amount of the text is redundant.

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 12-parameter layer-creation tool with no annotations and no output schema, the description covers what the layer looks like but not the surrounding workflow: no mention of layer ordering, depth-lane interaction, or return value. An agent could call it, but would be guessing about side effects on the existing layer stack.

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 all 12 parameters are already documented, which sets the baseline at 3. The description adds only loose mapping between the named style families and the canopyStyle/preset options, and largely restates the preset enum values rather than explaining interaction between parameters (e.g., how density, irregularity, and atmosphericMode combine).

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 treeline silhouette band layer') and immediately clarifies the visual semantics: a dense canopy mass, not individual trees, with an irregular top edge. It explicitly contrasts itself with the sibling plant tool ('distinct from plugin-plants which renders individual specimens'), so an agent can route correctly without opening the schema.

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?

Gives a clear selection rule against the most confusable sibling (treeline vs. individual plant specimens) and names the supported style families. It stops short of explicit when-not guidance relative to other landscape siblings (terrain profile, forest scene creators) and states no prerequisites such as an open sketch or target depth lane.

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