Add layer

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

Annotations declare non-readonly and non-idempotent; the description reinforces this by saying each call adds another layer and where it lands (on top unless moveToIndex). It also discloses the return payload (new layer's index, id and name), which the annotations cannot express. It stops short of noting undo/recovery or that the target comp must be open.

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 layer-kind enumeration before the placement and return behavior. Dense but every clause carries information (sibling routing, defaults, return shape); the parenthetical asides are the only minor clutter.

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 27-param creation tool with no output schema, the description covers the return value, default placement, and conditional parameter applicability. Missing only ancillary context such as permission/open-project prerequisites or the undo path, which is a modest gap rather than a blocker.

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 coverage is 100% and all 27 parameters are individually documented, so the baseline is 3. The description adds cross-parameter semantics the schema cannot: text options apply only to text layers, moveToIndex overrides default top placement, and shape layers are created empty. That grouping genuinely helps the agent pick valid parameter subsets for a 27-param tool.

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 (add) and resource (one layer to a composition) and enumerates the supported layer kinds: solid, text, shape, null, adjustment, camera, light, item. It explicitly carves out the empty-shape case to ae_add_shape, so an agent can separate this from the shape sibling without opening a 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?

Names the alternatives and the conditions that select them: use ae_add_shape to draw into an empty shape, ae_set_text to edit existing text, ae_set_layer_attributes (via ae_call) for switches/timing/parent. It also tells the agent that each call adds exactly one layer and lands on top unless moveToIndex is given, which is the key routing decision between repeat calls.

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