Capture the current 3D viewport as a base64-encoded PNG image.
AI agents call get_screenshot to retrieve information from FreeCAD MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves visual information from FreeCAD's viewport and returns it as image data. It has no side effects, does not modify any documents, execute code, delete data, or trigger external operations. It is purely observational. The presence of sibling tools like execute_script (Execute category) and the read-only nature of screenshot capture confirm this classification as Read.
From the tool's definition Tool description: 'Capture the current 3D viewport as a base64-encoded PNG image.' The verb 'capture' and the output specification (image data) indicate retrieval of visual state with no modifications to FreeCAD documents or external systems.
Documented attack patterns abuse exactly the kind of access get_screenshot gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and FreeCAD MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_screenshot:
{
"version": "1",
"default": "deny",
"tools": {
"get_screenshot": {}
}
}get_screenshot is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Capture the current 3D viewport as a base64-encoded PNG image. It is categorised as a Read tool in the FreeCAD MCP Server MCP Server, which means it retrieves data without modifying state.
Register the FreeCAD MCP Server MCP server in PolicyLayer and add a rule for get_screenshot: 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 FreeCAD MCP Server. Nothing to install.
get_screenshot 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 get_screenshot 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 get_screenshot. 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.
get_screenshot is provided by the FreeCAD MCP Server MCP server (theosib/freecad-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from FreeCAD MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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9 FreeCAD MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.