Replace a specific color in an Aseprite cel with a new color while preserving alpha, using adjustable tolerance to match similar colors.
Replace a cel color while preserving alpha and allowing channel tolerance.
| Name | Required | Description | Default |
|---|---|---|---|
| filename | Yes | ||
| to_color | Yes | ||
| tolerance | No | ||
| from_color | Yes | ||
| layer_name | Yes | ||
| frame_index | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the behavioral burden. It does add two useful behavioral details: alpha is preserved and tolerance applies per channel. However, it omits obvious mutation consequences, whether the replacement is in-place, what happens with no matching pixels, or what the return value indicates.
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?
One concise, front-loaded sentence with no filler. It immediately names the operation and then adds the two most important behavioral qualifiers, making it easy for an agent to scan and retain.
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 mutating tool with six parameters, no annotations, and no output schema, this description is too sparse. It leaves the agent without information about effect scope, required context, failure behavior, return values, or how the tolerance setting changes matching behavior beyond the word 'tolerance'.
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?
Schema description coverage is 0%, so the description must compensate. It weakly implies the roles of from_color and to_color and hints at tolerance, but it does not explain filename, layer_name, frame_index, color formats, or the meaning/range of tolerance despite six parameters needing clarification.
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 and resource: 'Replace a cel color', plus the key constraints 'preserving alpha' and 'allowing channel tolerance'. It is clear enough to distinguish from broader palette-level tools like set_palette or remap_colors_in_cel_range, though it does not explicitly name alternatives.
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?
No guidance is given about when to use this tool versus sibling tools such as erase_color, remap_colors_in_cel_range, or set_palette. The description implies a use case but provides no exclusions, prerequisites, or alternative routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.