aseprite-mcp

aseprite_transform

Flip, rotate by 90/180/270, or add a 1px outline to pixel art to make sprites readable on any background. Transform sprites, layers, or frames.

Instructions

Flip, rotate by 90/180/270, or add a 1 px outline to the artwork. Outlines are the classic way to make sprite art read clearly against any background.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "action": "<action>"
    },
    "name": "aseprite_transform"
  }
}

Input Schema

Name	Required	Description
`axis`	No	Flip axis (default horizontal).
`color`	No	Outline colour (default black).
`layer`	No	Layer name for target "layer" or for outlining a single layer.
`action`	Yes	What to do.
`frames`	No	Limit the transform to these frame indices.
`target`	No	Scope of the operation (default sprite).
`degrees`	No	Rotation angle (default 90).
`outside`	No	For outline: draw outside the silhouette (default true).
`document`	No	Document to act on: a short name inside the art folder ("hero"), a relative path, or an absolute .aseprite path. Omit to use the active document.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 27, 2026

TDQS

B3.2/5.0

Behavior2/5

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

With no annotations at all, the description carries the full behavioral burden and falls short: it never says the operation mutates the active document in place, whether it is reversible/undoable, or what happens to layers/frames not targeted. The one behavioral fact it does add -- the outline is fixed at 1 px (no width parameter exists in the schema) -- is genuinely useful but not enough.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the three actions. The second sentence about outlines reading clearly against backgrounds is flavor, but it is short and clarifies the intent of the outline action, so it earns most of its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 9-parameter, in-place mutation tool with no annotations and no output schema, the description is only minimally sufficient. It conveys what the actions are but omits mutation semantics, scope defaults, and any interplay between action/target/frames that an agent must get right.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so every parameter is already documented and the baseline is 3. The description adds the fixed 1 px outline width, which is not represented in the schema at all, and restates the rotation angles; it adds modest value but no syntax or interaction detail beyond that.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states three specific verbs (flip, rotate, outline) applied to 'the artwork', with the rotation angles spelled out. No sibling tool overlaps with these transforms (resize/crop/scale are geometry changes of a different kind), so an agent can route here unambiguously.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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 alternatives, no prerequisite or state notes, and no mention of which document/layer context is used. The single hint is 'artwork', which is not an actionable condition.

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

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