OpenNest/docs/plans/2026-03-08-mcp-service-design.md

OpenNest MCP Service + IO Library Refactor

Goal

Create an MCP server so Claude Code can load nest files, run nesting algorithms, and inspect results — enabling rapid iteration on nesting strategies without launching the WinForms app.

Project Changes

OpenNest.Core          (no external deps)  — add Plate.GetRemnants()
OpenNest.Engine        → Core
OpenNest.IO (NEW)      → Core + ACadSharp  — extracted from OpenNest/IO/
OpenNest.Mcp (NEW)     → Core + Engine + IO
OpenNest (WinForms)    → Core + Engine + IO (drops ACadSharp direct ref)

OpenNest.IO Library

New class library. Move from the UI project (OpenNest/IO/):

• DxfImporter
• DxfExporter
• NestReader
• NestWriter
• ProgramReader
• ACadSharp NuGet dependency (3.1.32)

The WinForms project drops its direct ACadSharp reference and references OpenNest.IO instead.

Plate.GetRemnants()

Add to Plate in Core. Simple strip-based scan:

1. Collect all part bounding boxes inflated by PartSpacing.
2. Scan the work area for clear rectangular strips along edges and between part columns/rows.
3. Return List<Box> of usable empty regions.

No engine dependency — uses only work area and part bounding boxes already available on Plate.

MCP Tools

Input

Tool	Description
load_nest	Load a .nest zip file, returns nest summary (plates, drawings, part counts)
import_dxf	Import a DXF file as a drawing
create_drawing	Create from built-in shape primitive (rect, circle, L, T) or raw G-code string

Setup

Tool	Description
create_plate	Define a plate with dimensions, spacing, edge spacing, quadrant
clear_plate	Remove all parts from a plate

Nesting

Tool	Description
fill_plate	Fill entire plate with a single drawing (NestEngine.Fill)
fill_area	Fill a specific box region on a plate
fill_remnants	Auto-detect remnants via Plate.GetRemnants(), fill each with a drawing
pack_plate	Multi-drawing bin packing (NestEngine.Pack)

Inspection

Tool	Description
get_plate_info	Dimensions, part count, utilization %, remnant boxes
get_parts	List placed parts with location, rotation, bounding box
check_overlaps	Run overlap detection, return collision points

Example Workflow

load_nest("N0308-008.zip")
→ 1 plate (36x36), 75 parts, 1 drawing (Converto 3 YRD DUMPER), utilization 80.2%

get_plate_info(plate: 0)
→ utilization: 80.2%, remnants: [{x:33.5, y:0, w:2.5, h:36}]

fill_remnants(plate: 0, drawing: "Converto 3 YRD DUMPER")
→ added 3 parts, new utilization: 83.1%

check_overlaps(plate: 0)
→ no overlaps

MCP Server Implementation

• .NET 8 console app using stdio transport
• Published to ~/.claude/mcp/OpenNest.Mcp/
• Registered in ~/.claude/settings.local.json
• In-memory state: holds the current Nest object across tool calls