Set the active layer in an Aseprite file by name, creating it when missing. Provide filename and layer name to target the correct layer.
Set the active layer by name, optionally creating it.
| Name | Required | Description | Default |
|---|---|---|---|
| filename | Yes | ||
| layer_name | Yes | ||
| create_if_missing | No |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are present, so the description must fully disclose behavior. It only mentions the core action and optional creation, but does not state what happens when create_if_missing is false and the layer doesn't exist, whether the previous active layer is changed or preserved, or any other side effects. This is too thin for a state-changing tool.
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 description is a single sentence with no filler. It front-loads the core verb and resource, then adds the key qualifying behavior. Every word contributes to the meaning, so it earns full marks for conciseness.
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 3 parameters, no annotations, and no output schema, the description must provide a complete mental model. It explains the overall function but leaves critical gaps: the role of filename, failure behavior, and what 'active layer' means in practice. An agent would not be able to call this tool confidently on a failure-path or edge case.
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?
The schema has zero description coverage for any parameter. The description adds meaning for layer_name ('by name') and create_if_missing ('optionally creating'), but completely omits filename, and doesn't clarify valid names or the exact semantics of the create flag beyond that. It only partially compensates for the missing schema descriptions.
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?
The description states a specific verb ('set') and resource ('active layer'), with an optional creation qualifier. It is distinct from property-manipulation siblings like set_layer_visibility or set_layer_blend_mode, but it doesn't explicitly differentiate from add_layer, which also creates layers, so it falls just short of fully distinguishing itself.
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 use this tool versus alternatives like add_layer or ensure_layers_present. The phrase 'optionally creating it' implies a use case (set active while maybe creating), but no exclusions, prerequisites, or alternative tool references are provided, leaving the agent without clear routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.