feat(agent): share Web UI compatible drawing builders between MCP and copilot

The text drawing tool was MCP-only; the copilot needs the same
capability and its area-annotation helper carried the same Web UI
compat bugs. Split into three layers with a single implementation:

- gns3server/utils/drawings.py: pure SVG builders (text, rectangle,
  ellipse) with full input validation (ValueError) — the Web UI
  format knowledge lives in core utils next to picture.py
- api_handlers.py: shared REST handlers (create_text_drawing_handler
  moved here, create_rectangle/ellipse_drawing_handler added) — the
  layer both consumers already share
- thin shells: MCP tools (drawing_create_text unchanged, plus new
  drawing_create_rectangle/_ellipse) and three LangChain tools
  (tools_v2/gns3_create_drawing.py) registered in both copilot mode
  lists

Shape builder details:

- rectangle: solid fill or "none", stroke block emitted only when a
  stroke is given, rx corner radius, dasharray validated against the
  Web UI's Qt remap table (QtDasharrayFixer rewrites those patterns)
- ellipse: bounding-box API; cx/cy derived as offsets inside the
  drawing box (the Web UI treats them as box-relative, not canvas
  coordinates); odd sizes round down and the actual size is returned

gns3_drawing_utils now delegates to the shared builders, fixing the
px-blind sizing, the ignored text-anchor/x/y centering and the
missing XML escaping in the area-annotation path.

gns3server/agent/gns3_copilot/tools_v2/__init__.py

@@ -40,6 +40,7 @@ Main modules:
 - vpcs_tools_netmiko: VPCS device configuration tool using Netmiko
 - gns3_create_node: GNS3 node creation tool
 - gns3_create_link: GNS3 link creation tool
+- gns3_create_drawing: GNS3 canvas drawing tools (text, rectangle, ellipse)
 - gns3_start_node: GNS3 node startup tool (immediate return, no boot wait)
 - gns3_wait: Wait timer tool (pair with node start to let devices boot)
 - gns3_get_node_temp: GNS3 template retrieval tool
@@ -54,6 +55,11 @@ Author: Yue Guobin (岳国宾)
 # Import main tool classes
 from .config_tools_nornir import ExecuteMultipleDeviceConfigCommands
 from .display_tools_nornir import ExecuteMultipleDeviceCommands
+from .gns3_create_drawing import (
+    GNS3CreateEllipseDrawingTool,
+    GNS3CreateRectangleDrawingTool,
+    GNS3CreateTextDrawingTool,
+)
 from .gns3_create_link import GNS3LinkTool
 from .gns3_create_node import GNS3CreateNodeTool
 from .gns3_get_node_temp import GNS3TemplateTool
@@ -81,7 +87,10 @@ __url__ = "https://github.com/yueguobin/gns3-copilot"
 __all__ = [
     "ExecuteMultipleDeviceCommands",
     "ExecuteMultipleDeviceConfigCommands",
+    "GNS3CreateEllipseDrawingTool",
     "GNS3CreateNodeTool",
+    "GNS3CreateRectangleDrawingTool",
+    "GNS3CreateTextDrawingTool",
     "GNS3LinkTool",
     "GNS3PacketFilterTool",
     "GNS3StartNodeQuickTool",

gns3server/agent/gns3_copilot/tools_v2/gns3_create_drawing.py

@@ -0,0 +1,162 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# GNS3-Copilot - AI-powered Network Lab Assistant for GNS3
+#
+# This file is part of GNS3-Copilot project.
+#
+# GNS3-Copilot is free software: you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation, either version 3 of the License, or (at your
+# option) any later version.
+#
+# GNS3-Copilot is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GNS3-Copilot. If not, see <https://www.gnu.org/licenses/>.
+#
+# Copyright (C) 2025 Yue Guobin (岳国宾)
+# Author: Yue Guobin (岳国宾)
+#
+# Project Home: https://github.com/yueguobin/gns3-copilot
+#
+
+"""
+GNS3 canvas drawing tools for text, rectangle and ellipse annotations.
+
+Thin LangChain wrappers over the shared REST handlers in
+``gns3_client.api_handlers``; the Web UI compatible SVG is assembled and
+validated by ``gns3server.utils.drawings`` (single implementation shared
+with the MCP drawing tools).
+"""
+
+import json
+import logging
+from typing import Any
+
+from langchain.tools import BaseTool
+from langchain_core.callbacks import CallbackManagerForToolRun
+
+from gns3server.agent.gns3_copilot.gns3_client.api_handlers import (
+    build_gns3_ctx,
+    create_ellipse_drawing_handler,
+    create_rectangle_drawing_handler,
+    create_text_drawing_handler,
+)
+
+# Configure logging
+logger = logging.getLogger(__name__)
+
+
+class _GNS3CreateDrawingToolBase(BaseTool):
+    """Shared plumbing: parse JSON input, build ctx, dispatch to a handler."""
+
+    def _dispatch(self, input_data: dict[str, Any], gns3_ctx: dict[str, Any]) -> dict[str, Any]:
+        raise NotImplementedError
+
+    def _run(
+        self,
+        tool_input: str,
+        run_manager: CallbackManagerForToolRun | None = None,
+    ) -> dict[str, Any]:
+        try:
+            input_data = json.loads(tool_input)
+
+            gns3_ctx = build_gns3_ctx()
+            if gns3_ctx is None:
+                logger.error("Failed to create GNS3 connector")
+                return {"error": "Failed to connect to GNS3 server. Please check your configuration."}
+
+            return self._dispatch(input_data, gns3_ctx)
+        except json.JSONDecodeError as e:
+            logger.error("Invalid JSON input: %s", e)
+            return {"error": f"Invalid JSON input: {e}"}
+        except Exception as e:
+            logger.exception("Drawing creation failed")
+            return {"error": str(e)}
+
+
+class GNS3CreateTextDrawingTool(_GNS3CreateDrawingToolBase):
+    """
+    A LangChain tool to add a text label to the GNS3 project canvas.
+
+    **Input**:
+    A JSON object with project_id, x, y (top-left corner on the canvas)
+    and text; optional font_size (1-200, default 13), color (#RRGGBB,
+    default #000000), bold (default false), font_family (default
+    monospace) and z (default 1, keeps text above links).
+    Newlines in text start additional lines; XML characters are escaped
+    automatically; the computed width/height are returned.
+
+    **Output**:
+    A dictionary with the created drawing, its drawing_id and the
+    computed width/height/line_height, or an "error" key on failure.
+    """
+
+    name: str = "create_gns3_text_drawing"
+    description: str = """
+    Adds a text label to the GNS3 project canvas.
+    Input: JSON with project_id, x, y (top-left corner), text and optional
+    font_size, color, bold, font_family, z.
+    Returns: the created drawing with its computed width and height.
+    """
+
+    def _dispatch(self, input_data: dict[str, Any], gns3_ctx: dict[str, Any]) -> dict[str, Any]:
+        return create_text_drawing_handler(input_data, gns3_ctx)
+
+
+class GNS3CreateRectangleDrawingTool(_GNS3CreateDrawingToolBase):
+    """
+    A LangChain tool to add a rectangle to the GNS3 project canvas.
+
+    **Input**:
+    A JSON object with project_id, x, y (top-left corner), width and
+    height (1-2000); optional fill (#RRGGBB or "none", default #FFFFFF),
+    fill_opacity (0-1, default 1.0), stroke (#RRGGBB, no border by
+    default), stroke_width (1-20), dashed (bool), dasharray (like "4,2",
+    requires stroke) and rx (corner radius, default 0). z defaults to 0
+    so shapes stay behind nodes and text.
+
+    **Output**:
+    A dictionary with the created drawing, or an "error" key on failure.
+    """
+
+    name: str = "create_gns3_rectangle_drawing"
+    description: str = """
+    Adds a rectangle to the GNS3 project canvas.
+    Input: JSON with project_id, x, y, width, height and optional fill,
+    fill_opacity, stroke, stroke_width, dashed, dasharray, rx, z.
+    Returns: the created drawing with its width and height.
+    """
+
+    def _dispatch(self, input_data: dict[str, Any], gns3_ctx: dict[str, Any]) -> dict[str, Any]:
+        return create_rectangle_drawing_handler(input_data, gns3_ctx)
+
+
+class GNS3CreateEllipseDrawingTool(_GNS3CreateDrawingToolBase):
+    """
+    A LangChain tool to add an ellipse (or circle) to the GNS3 canvas.
+
+    **Input**:
+    A JSON object with project_id, x, y (bounding box top-left corner),
+    width and height (2-2000, equal values give a circle); the same
+    optional style fields as the rectangle tool. cx/cy are derived from
+    the bounding box; for odd width/height the drawing is 1 px smaller
+    than requested and the actual size is returned.
+
+    **Output**:
+    A dictionary with the created drawing, or an "error" key on failure.
+    """
+
+    name: str = "create_gns3_ellipse_drawing"
+    description: str = """
+    Adds an ellipse or circle to the GNS3 project canvas.
+    Input: JSON with project_id, x, y, width, height (bounding box) and
+    optional fill, fill_opacity, stroke, stroke_width, dashed, dasharray, z.
+    Returns: the created drawing with its actual width and height.
+    """
+
+    def _dispatch(self, input_data: dict[str, Any], gns3_ctx: dict[str, Any]) -> dict[str, Any]:
+        return create_ellipse_drawing_handler(input_data, gns3_ctx)