AI agents use add_external_geometry to create or update resources in FreeCAD Robust MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your FreeCAD Robust MCP Server environment.
This tool creates or modifies geometry in FreeCAD sketches by adding external geometry references. While the description is unavailable, the naming pattern and context of sibling tools that perform additive/constructive operations strongly suggest a Write category (reversible modification). It does not execute arbitrary code, delete data, or move financial resources.
From the tool's definition Tool name 'add_external_geometry' indicates creation/addition of geometric elements in FreeCAD; sibling tools like 'add_sketch_line', 'add_sketch_circle', 'add_sketch_constraint' all perform Write operations (creating/modifying sketch geometry).
Documented attack patterns abuse exactly the kind of access add_external_geometry gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and FreeCAD Robust MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add_external_geometry:
{
"version": "1",
"default": "deny",
"tools": {
"add_external_geometry": {
"limits": [
{
"counter": "add_external_geometry_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_external_geometry 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.
add_external_geometry. It is categorised as a Write tool in the FreeCAD Robust MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the FreeCAD Robust MCP Server MCP server in PolicyLayer and add a rule for add_external_geometry: 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 Robust MCP Server. Nothing to install.
add_external_geometry 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 add_external_geometry 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 add_external_geometry. 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.
add_external_geometry is provided by the FreeCAD Robust MCP Server MCP server (spkane/freecad-addon-robust-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 152 FreeCAD Robust MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
152 FreeCAD Robust MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.