Medium Risk

add_sketch_line

Add a line to a sketch. Args: sketch_name: Name of the sketch to add line to. x1: X coordinate of start point. y1: Y coordinate of start point. x2: X coordinate of end point. y2: Y coordinate of end point. construction: Whether this is a construction line. Defaults to False. doc_name: Document co...

How to control add_sketch_line ↓

AI agents use add_sketch_line 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.

Medium Risk

This tool creates or modifies CAD design data within a FreeCAD sketch. The operation is reversible (lines can be deleted), so it falls under Write rather than Destructive. The severity is medium because misuse could corrupt complex CAD models or introduce unwanted geometry that requires manual cleanup, but the impact is limited to a single sketch unless the entire model depends on it.

From the tool's definition Tool description states 'Add a line to a sketch' which creates new geometry in FreeCAD. The function signature includes parameters for line coordinates and construction mode, modifying sketch content.

Documented attack patterns abuse exactly the kind of access add_sketch_line 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_sketch_line:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_sketch_line": {
      "limits": [
        {
          "counter": "add_sketch_line_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

add_sketch_line 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.

  1. Create a free account and register FreeCAD Robust MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Go deeper

What does the add_sketch_line tool do? +

Add a line to a sketch. Args: sketch_name: Name of the sketch to add line to. x1: X coordinate of start point. y1: Y coordinate of start point. x2: X coordinate of end point. y2: Y coordinate of end point. construction: Whether this is a construction line. Defaults to False. doc_name: Document containing the sketch. Uses active document if None. Returns: Dictionary with geometry info: - geometry_index: Index of the added line - geometry_count: Total geometry elements. 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.

How do I enforce a policy on add_sketch_line? +

Register the FreeCAD Robust MCP Server MCP server in PolicyLayer and add a rule for add_sketch_line: 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.

What risk level is add_sketch_line? +

add_sketch_line is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit add_sketch_line? +

Yes. Add a rate_limit block to the add_sketch_line 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.

How do I block add_sketch_line completely? +

Set action: deny in the PolicyLayer policy for add_sketch_line. 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.

What MCP server provides add_sketch_line? +

add_sketch_line 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.

Enforce policy on every FreeCAD Robust MCP Server tool call.

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.

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