lentera-aseprite-mcp

set_active_frame

Set the active animation frame in Aseprite by specifying its number, allowing direct navigation to any frame for editing or review.

Instructions

Set the active frame (navigate to a specific frame).

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": {
      "frame_number": "<frame_number>"
    },
    "name": "set_active_frame"
  }
}

Input Schema

Name	Required	Description	Default
`frame_number`	Yes	Frame number to activate (1-based)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 14, 2026

TDQS

B3.3/5.0

Behavior2/5

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

With no annotations, the description carries the full burden. It only restates the core action without disclosing any side effects, prerequisites, range limitations, or behavior on invalid frame numbers. The schema notes 1-based indexing, but that is parameter semantics, not behavioral context.

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?

The description is a single, front-loaded sentence with no unnecessary words. It effectively communicates the tool's purpose in minimal space.

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 simple single-parameter setter with no output schema, the description plus schema provide the basic information needed to make an initial call. However, it lacks usage context and behavioral caveats that would be useful for an agent, especially given the absence of annotations.

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?

The description adds no information about the frame_number parameter beyond what the schema already provides. Since schema description coverage is 100% ('Frame number to activate (1-based)'), the baseline score of 3 applies.

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 clearly states the action: 'Set the active frame' and clarifies the intent with '(navigate to a specific frame)'. This specific verb+resource phrasing distinguishes it from sibling frame tools like add_frame, remove_frame, and set_frame_duration.

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?

No explicit guidance is provided on when to use this tool vs alternatives. The usage is only implied by the name and description, with no mention of prerequisites (e.g., an open sprite) or edge cases.

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