Replace all occurrences of a color with another color. Can operate on a single frame, all frames, or all layers.
AI agents use replace_color to create or update resources in Piskel MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Piskel MCP Server environment.
The tool modifies pixel art data by changing colors, which is a write operation. It is reversible (the original colors are not permanently deleted, and the operation can be undone by replacing back), so it does not qualify as Destructive. The scope across frames/layers could affect significant portions of a project, but the operation itself is non-destructive and user-intended, placing it at medium severity.
From the tool's definition Tool description states it 'Replace[s] all occurrences of a color with another color' with scope options including 'a single frame, all frames, or all layers.' This is a modification operation.
Documented attack patterns abuse exactly the kind of access replace_color gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Piskel MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for replace_color:
{
"version": "1",
"default": "deny",
"tools": {
"replace_color": {
"limits": [
{
"counter": "replace_color_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}replace_color stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Replace all occurrences of a color with another color. Can operate on a single frame, all frames, or all layers. It is categorised as a Write tool in the Piskel MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Piskel MCP Server MCP server in PolicyLayer and add a rule for replace_color: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Piskel MCP Server. Nothing to install.
replace_color is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the replace_color rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for replace_color. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
replace_color is provided by the Piskel MCP Server MCP server (yafeiaa/piskel-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Piskel MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
45 Piskel MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.