Recolor sprites by shifting hue. Reads PNGs from an input folder, shifts pixels in a source hue range to a target hue, writes results to output folder. Perfect for creating color variants of character sprites (e.g. red shirt → blue shirt).
AI agents use hue_shift_recolor 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 reads existing PNG files and writes new/modified image files to an output folder. This is a reversible write operation (creating new files with color variants), not destructive since originals remain in the input folder. The blast radius is medium as it could overwrite existing files in the output folder.
From the tool's definition reads PNGs from an input folder, shifts pixels in a source hue range to a target hue, writes results to output folder
Documented attack patterns abuse exactly the kind of access hue_shift_recolor 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 hue_shift_recolor:
{
"version": "1",
"default": "deny",
"tools": {
"hue_shift_recolor": {
"limits": [
{
"counter": "hue_shift_recolor_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}hue_shift_recolor 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.
Recolor sprites by shifting hue. Reads PNGs from an input folder, shifts pixels in a source hue range to a target hue, writes results to output folder. Perfect for creating color variants of character sprites (e.g. red shirt → blue shirt). 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 hue_shift_recolor: 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.
hue_shift_recolor 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 hue_shift_recolor 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 hue_shift_recolor. 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.
hue_shift_recolor 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.