add_layer

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful context that the created layer is empty and placed at the top of the stack, but says nothing about what happens to the active selection, whether the layer becomes selected/current, or return behavior.

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 first sentence fully front-loads the action, and the Args block is terse. The long blend_mode list is the only bulk, and it is necessary information not available elsewhere.

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 6-param mutation with no output schema and annotations covering safety, the description covers nearly everything needed to invoke it correctly. The lone gap is the undocumented required 'filename' parameter, which forces the agent to guess which sprite file is targeted.

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?

With 50% schema coverage and zero schema enums, the description carries real weight: it enumerates all 18 legal blend_mode values (absent from the schema) and documents name, group, opacity and visible. Only 'filename' is left undocumented, which keeps it short of a 5.

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 concrete verb+resource (add a layer) and narrows it with 'new (empty) normal layer on top of the stack', which distinguishes it from sibling operations like add_group_layer and duplicate_layer. It does not explicitly name those siblings, but the type and placement are 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?

Usage is only implied: 'on top of the stack' tells the agent where the layer lands, and 'normal layer' hints at the alternative of a group layer. There is no explicit when-to-use/when-not or routing to add_group_layer or add_reference_layer, so the agent must infer.

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