aseprite-mcp

aseprite_set_frame_duration

Set frame durations in milliseconds across all frames or a specific range to control animation playback speed, e.g. 100 ms for 10 fps.

Instructions

Set frame durations in milliseconds. Applies to a range when from/to are given, otherwise to every frame. 100 ms = 10 fps is a good default; 40-80 ms suits fast actions like a run cycle.

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": {
      "durationMs": "<durationMs>"
    },
    "name": "aseprite_set_frame_duration"
  }
}

Input Schema

Name	Required	Description
`to`	No	Zero-based frame index (omit for the first frame).
`from`	No	Zero-based frame index (omit for the first frame).
`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.
`durationMs`	Yes	Duration in milliseconds (default 100).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Sep 27, 2026

TDQS

A4.2/5.0

Behavior3/5

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

With no annotations, the description carries the full behavioral burden. It usefully discloses that the operation targets a range or every frame, but omits side effects such as whether changes are undoable, whether a document must be open, and what the response looks like.

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

Conciseness5/5

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

Three tight sentences with the core action front-loaded, followed by scope behavior and practical defaults. Every sentence adds useful information without repetition or filler.

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

Completeness4/5

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

For a four-parameter setter with full schema descriptions and no output schema, the definition is nearly complete: it covers action, scope, and timing guidance. It could be more complete by mentioning mutation side effects or undo behavior, but the schema already covers document and index semantics.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3, but the description adds genuine semantic value: it clarifies the interaction of `from`/`to` as a range selector and gives practical meaning for `durationMs` via the 100 ms = 10 fps equivalence and 40–80 ms guidance for fast actions.

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 a specific verb and resource: set frame durations in milliseconds. This is inherently distinct from every sibling tool, none of which manipulate frame timing, so an agent can identify it 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.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly explains the range behavior when `from`/`to` are given and the fallback to all frames, and gives recommended duration values with a practical example. It does not explicitly compare to alternatives or state when not to use it, but the context is clear.

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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