preview_luminance_mask
AI agents call preview_luminance_mask to retrieve information from Rawtherapee without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears designed to display or visualize a luminance mask for the user's inspection within the RAW photo development workflow. No write, execute, or destructive operations are indicated by the name. The empty description lowers confidence slightly, but the naming convention and sibling tools (which include 'analyze_image', 'apply_*' operations) suggest this is a non-modifying visualization tool.
From the tool's definition Tool name 'preview_luminance_mask' contains 'preview', indicating a visual inspection/read operation. In image editing contexts, previewing a mask is a non-destructive read operation that displays the result of a luminance mask without modifying underlying…
Attacks that exploit this kind of access
preview_luminance_mask. It is categorised as a Read tool in the Rawtherapee MCP Server, which means it retrieves data without modifying state.
Register the Rawtherapee MCP server in PolicyLayer and add a rule for preview_luminance_mask: 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 Rawtherapee. Nothing to install.
preview_luminance_mask is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the preview_luminance_mask 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 preview_luminance_mask. 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.
preview_luminance_mask is provided by the Rawtherapee MCP server (lucamarien/rawtherapee-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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