OpenNest/docs/superpowers/plans/2026-03-15-abstract-nest-engine.md

Abstract Nest Engine Implementation Plan

For agentic workers: REQUIRED: Use superpowers:subagent-driven-development (if subagents available) or superpowers:executing-plans to implement this plan. Steps use checkbox (- [ ]) syntax for tracking.

Goal: Refactor the concrete NestEngine into an abstract NestEngineBase with pluggable implementations, a registry for engine discovery/selection, and plugin loading from DLLs.

Architecture: Extract shared state and utilities into NestEngineBase (abstract). Current logic becomes DefaultNestEngine. NestEngineRegistry provides factory creation, built-in registration, and DLL plugin discovery. All callsites migrate from new NestEngine(plate) to NestEngineRegistry.Create(plate).

Tech Stack: C# / .NET 8, OpenNest.Engine, OpenNest (WinForms), OpenNest.Mcp, OpenNest.Console

Spec: docs/superpowers/specs/2026-03-15-abstract-nest-engine-design.md

Deferred: StripNester.cs → StripNestEngine.cs conversion is deferred to the strip nester implementation plan (docs/superpowers/plans/2026-03-15-strip-nester.md). That plan should be updated to create StripNestEngine as a NestEngineBase subclass and register it in NestEngineRegistry. The UI engine selector combobox is also deferred — it can be added once there are multiple engines to choose from.

---

Chunk 1: NestEngineBase and DefaultNestEngine

Task 1: Create NestEngineBase abstract class

Files:

• Create: OpenNest.Engine/NestEngineBase.cs

This is the abstract base class. It holds shared properties, abstract Name/Description, virtual methods that return empty lists by default, convenience overloads that mutate the plate, FillExact (non-virtual), and protected utility methods extracted from the current NestEngine.

• Step 1: Create NestEngineBase.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using OpenNest.Geometry;

namespace OpenNest
{
    public abstract class NestEngineBase
    {
        protected NestEngineBase(Plate plate)
        {
            Plate = plate;
        }

        public Plate Plate { get; set; }

        public int PlateNumber { get; set; }

        public NestDirection NestDirection { get; set; }

        public NestPhase WinnerPhase { get; protected set; }

        public List<PhaseResult> PhaseResults { get; } = new();

        public List<AngleResult> AngleResults { get; } = new();

        public abstract string Name { get; }

        public abstract string Description { get; }

        // --- Virtual methods (side-effect-free, return parts) ---

        public virtual List<Part> Fill(NestItem item, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)
        {
            return new List<Part>();
        }

        public virtual List<Part> Fill(List<Part> groupParts, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)
        {
            return new List<Part>();
        }

        public virtual List<Part> PackArea(Box box, List<NestItem> items,
            IProgress<NestProgress> progress, CancellationToken token)
        {
            return new List<Part>();
        }

        // --- FillExact (non-virtual, delegates to virtual Fill) ---

        public List<Part> FillExact(NestItem item, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)
        {
            return Fill(item, workArea, progress, token);
        }

        // --- Convenience overloads (mutate plate, return bool) ---

        public bool Fill(NestItem item)
        {
            return Fill(item, Plate.WorkArea());
        }

        public bool Fill(NestItem item, Box workArea)
        {
            var parts = Fill(item, workArea, null, CancellationToken.None);

            if (parts == null || parts.Count == 0)
                return false;

            Plate.Parts.AddRange(parts);
            return true;
        }

        public bool Fill(List<Part> groupParts)
        {
            return Fill(groupParts, Plate.WorkArea());
        }

        public bool Fill(List<Part> groupParts, Box workArea)
        {
            var parts = Fill(groupParts, workArea, null, CancellationToken.None);

            if (parts == null || parts.Count == 0)
                return false;

            Plate.Parts.AddRange(parts);
            return true;
        }

        public bool Pack(List<NestItem> items)
        {
            var workArea = Plate.WorkArea();
            var parts = PackArea(workArea, items, null, CancellationToken.None);

            if (parts == null || parts.Count == 0)
                return false;

            Plate.Parts.AddRange(parts);
            return true;
        }

        // --- Protected utilities ---

        protected static void ReportProgress(
            IProgress<NestProgress> progress,
            NestPhase phase,
            int plateNumber,
            List<Part> best,
            Box workArea,
            string description)
        {
            if (progress == null || best == null || best.Count == 0)
                return;

            var score = FillScore.Compute(best, workArea);
            var clonedParts = new List<Part>(best.Count);
            var totalPartArea = 0.0;

            foreach (var part in best)
            {
                clonedParts.Add((Part)part.Clone());
                totalPartArea += part.BaseDrawing.Area;
            }

            var bounds = best.GetBoundingBox();

            var msg = $"[Progress] Phase={phase}, Plate={plateNumber}, Parts={score.Count}, " +
                      $"Density={score.Density:P1}, Nested={bounds.Width:F1}x{bounds.Length:F1}, " +
                      $"PartArea={totalPartArea:F0}, Remnant={workArea.Area() - totalPartArea:F0}, " +
                      $"WorkArea={workArea.Width:F1}x{workArea.Length:F1} | {description}";
            Debug.WriteLine(msg);
            try { System.IO.File.AppendAllText(
                System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "nest-debug.log"),
                $"{DateTime.Now:HH:mm:ss.fff} {msg}\n"); } catch { }

            progress.Report(new NestProgress
            {
                Phase = phase,
                PlateNumber = plateNumber,
                BestPartCount = score.Count,
                BestDensity = score.Density,
                NestedWidth = bounds.Width,
                NestedLength = bounds.Length,
                NestedArea = totalPartArea,
                UsableRemnantArea = workArea.Area() - totalPartArea,
                BestParts = clonedParts,
                Description = description
            });
        }

        protected string BuildProgressSummary()
        {
            if (PhaseResults.Count == 0)
                return null;

            var parts = new List<string>(PhaseResults.Count);

            foreach (var r in PhaseResults)
                parts.Add($"{FormatPhaseName(r.Phase)}: {r.PartCount}");

            return string.Join(" | ", parts);
        }

        protected bool IsBetterFill(List<Part> candidate, List<Part> current, Box workArea)
        {
            if (candidate == null || candidate.Count == 0)
                return false;

            if (current == null || current.Count == 0)
                return true;

            return FillScore.Compute(candidate, workArea) > FillScore.Compute(current, workArea);
        }

        protected bool IsBetterValidFill(List<Part> candidate, List<Part> current, Box workArea)
        {
            if (candidate != null && candidate.Count > 0 && HasOverlaps(candidate, Plate.PartSpacing))
            {
                Debug.WriteLine($"[IsBetterValidFill] REJECTED {candidate.Count} parts due to overlaps (current best: {current?.Count ?? 0})");
                return false;
            }

            return IsBetterFill(candidate, current, workArea);
        }

        protected static bool HasOverlaps(List<Part> parts, double spacing)
        {
            if (parts == null || parts.Count <= 1)
                return false;

            for (var i = 0; i < parts.Count; i++)
            {
                var box1 = parts[i].BoundingBox;

                for (var j = i + 1; j < parts.Count; j++)
                {
                    var box2 = parts[j].BoundingBox;

                    if (box1.Right < box2.Left || box2.Right < box1.Left ||
                        box1.Top < box2.Bottom || box2.Top < box1.Bottom)
                        continue;

                    List<Vector> pts;

                    if (parts[i].Intersects(parts[j], out pts))
                    {
                        var b1 = parts[i].BoundingBox;
                        var b2 = parts[j].BoundingBox;
                        Debug.WriteLine($"[HasOverlaps] Overlap: part[{i}] ({parts[i].BaseDrawing?.Name}) @ ({b1.Left:F2},{b1.Bottom:F2})-({b1.Right:F2},{b1.Top:F2}) rot={parts[i].Rotation:F2}" +
                            $" vs part[{j}] ({parts[j].BaseDrawing?.Name}) @ ({b2.Left:F2},{b2.Bottom:F2})-({b2.Right:F2},{b2.Top:F2}) rot={parts[j].Rotation:F2}" +
                            $" intersections={pts?.Count ?? 0}");
                        return true;
                    }
                }
            }

            return false;
        }

        protected static string FormatPhaseName(NestPhase phase)
        {
            switch (phase)
            {
                case NestPhase.Pairs: return "Pairs";
                case NestPhase.Linear: return "Linear";
                case NestPhase.RectBestFit: return "BestFit";
                case NestPhase.Remainder: return "Remainder";
                default: return phase.ToString();
            }
        }
    }
}

• Step 2: Build to verify

Run: dotnet build OpenNest.Engine/OpenNest.Engine.csproj Expected: Build succeeded

• Step 3: Commit

git add OpenNest.Engine/NestEngineBase.cs
git commit -m "feat: add NestEngineBase abstract class"

---

Task 2: Convert NestEngine to DefaultNestEngine

Files:

• Rename: OpenNest.Engine/NestEngine.cs → OpenNest.Engine/DefaultNestEngine.cs

Rename the class, make it inherit NestEngineBase, add Name/Description, change the virtual methods to override, and remove methods that now live in the base class (convenience overloads, ReportProgress, BuildProgressSummary, IsBetterFill, IsBetterValidFill, HasOverlaps, FormatPhaseName, FillExact).

• Step 1: Rename the file

git mv OpenNest.Engine/NestEngine.cs OpenNest.Engine/DefaultNestEngine.cs

• Step 2: Update class declaration and add inheritance

In DefaultNestEngine.cs, change the class declaration from:

    public class NestEngine
    {
        public NestEngine(Plate plate)
        {
            Plate = plate;
        }

        public Plate Plate { get; set; }

        public NestDirection NestDirection { get; set; }

        public int PlateNumber { get; set; }

        public NestPhase WinnerPhase { get; private set; }

        public List<PhaseResult> PhaseResults { get; } = new();

        public bool ForceFullAngleSweep { get; set; }

        public List<AngleResult> AngleResults { get; } = new();

To:

    public class DefaultNestEngine : NestEngineBase
    {
        public DefaultNestEngine(Plate plate) : base(plate)
        {
        }

        public override string Name => "Default";

        public override string Description => "Multi-phase nesting (Linear, Pairs, RectBestFit, Remainder)";

        public bool ForceFullAngleSweep { get; set; }

This removes properties that now come from the base class (Plate, PlateNumber, NestDirection, WinnerPhase, PhaseResults, AngleResults).

• Step 3: Convert the convenience Fill overloads to override the virtual methods

Remove the non-progress Fill convenience overloads (they are now in the base class). The two remaining Fill methods that take IProgress<NestProgress> and CancellationToken become overrides.

Change:

        public List<Part> Fill(NestItem item, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)

To:

        public override List<Part> Fill(NestItem item, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)

Change:

        public List<Part> Fill(List<Part> groupParts, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)

To:

        public override List<Part> Fill(List<Part> groupParts, Box workArea,
            IProgress<NestProgress> progress, CancellationToken token)

Remove these methods entirely (now in base class):

• bool Fill(NestItem item) (2-arg convenience)

• bool Fill(NestItem item, Box workArea) (convenience that calls the 4-arg)

• bool Fill(List<Part> groupParts) (convenience)

• bool Fill(List<Part> groupParts, Box workArea) (convenience that calls the 4-arg)

• FillExact (now in base class)

• ReportProgress (now in base class)

• BuildProgressSummary (now in base class)

• IsBetterFill (now in base class)

• IsBetterValidFill (now in base class)

• HasOverlaps (now in base class)

• FormatPhaseName (now in base class)

• Step 4: Convert Pack/PackArea to override

Remove Pack(List<NestItem>) (now in base class).

Convert PackArea to override with the new signature. Replace:

        public bool Pack(List<NestItem> items)
        {
            var workArea = Plate.WorkArea();
            return PackArea(workArea, items);
        }

        public bool PackArea(Box box, List<NestItem> items)
        {
            var binItems = BinConverter.ToItems(items, Plate.PartSpacing, Plate.Area());
            var bin = BinConverter.CreateBin(box, Plate.PartSpacing);

            var engine = new PackBottomLeft(bin);
            engine.Pack(binItems);

            var parts = BinConverter.ToParts(bin, items);
            Plate.Parts.AddRange(parts);

            return parts.Count > 0;
        }

With:

        public override List<Part> PackArea(Box box, List<NestItem> items,
            IProgress<NestProgress> progress, CancellationToken token)
        {
            var binItems = BinConverter.ToItems(items, Plate.PartSpacing, Plate.Area());
            var bin = BinConverter.CreateBin(box, Plate.PartSpacing);

            var engine = new PackBottomLeft(bin);
            engine.Pack(binItems);

            return BinConverter.ToParts(bin, items);
        }

Note: the progress and token parameters are not used yet in the default rectangle packing — the contract is there for engines that need them.

• Step 5: Update BruteForceRunner to use DefaultNestEngine

BruteForceRunner.cs is in the same project and still references NestEngine. It must be updated before the Engine project can compile. This is the one callsite that stays as a direct DefaultNestEngine reference (not via registry) because training data must come from the known algorithm.

In OpenNest.Engine/ML/BruteForceRunner.cs, change line 30:

            var engine = new NestEngine(plate);

To:

            var engine = new DefaultNestEngine(plate);

• Step 6: Build to verify

Run: dotnet build OpenNest.Engine/OpenNest.Engine.csproj Expected: Build succeeded (other projects will have errors since their callsites still reference NestEngine — fixed in Chunk 3)

• Step 7: Commit

git add OpenNest.Engine/DefaultNestEngine.cs OpenNest.Engine/ML/BruteForceRunner.cs
git commit -m "refactor: rename NestEngine to DefaultNestEngine, inherit NestEngineBase"

---

Chunk 2: NestEngineRegistry and NestEngineInfo

Task 3: Create NestEngineInfo

Files:

• Create: OpenNest.Engine/NestEngineInfo.cs

• Step 1: Create NestEngineInfo.cs

using System;

namespace OpenNest
{
    public class NestEngineInfo
    {
        public NestEngineInfo(string name, string description, Func<Plate, NestEngineBase> factory)
        {
            Name = name;
            Description = description;
            Factory = factory;
        }

        public string Name { get; }
        public string Description { get; }
        public Func<Plate, NestEngineBase> Factory { get; }
    }
}

• Step 2: Build to verify

Run: dotnet build OpenNest.Engine/OpenNest.Engine.csproj Expected: Build succeeded

• Step 3: Commit

git add OpenNest.Engine/NestEngineInfo.cs
git commit -m "feat: add NestEngineInfo metadata class"

---

Task 4: Create NestEngineRegistry

Files:

• Create: OpenNest.Engine/NestEngineRegistry.cs

Static class with built-in registration, plugin loading, active engine selection, and factory creation.

• Step 1: Create NestEngineRegistry.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;

namespace OpenNest
{
    public static class NestEngineRegistry
    {
        private static readonly List<NestEngineInfo> engines = new();

        static NestEngineRegistry()
        {
            Register("Default",
                "Multi-phase nesting (Linear, Pairs, RectBestFit, Remainder)",
                plate => new DefaultNestEngine(plate));
        }

        public static IReadOnlyList<NestEngineInfo> AvailableEngines => engines;

        public static string ActiveEngineName { get; set; } = "Default";

        public static NestEngineBase Create(Plate plate)
        {
            var info = engines.FirstOrDefault(e =>
                e.Name.Equals(ActiveEngineName, StringComparison.OrdinalIgnoreCase));

            if (info == null)
            {
                Debug.WriteLine($"[NestEngineRegistry] Engine '{ActiveEngineName}' not found, falling back to Default");
                info = engines[0];
            }

            return info.Factory(plate);
        }

        public static void Register(string name, string description, Func<Plate, NestEngineBase> factory)
        {
            if (engines.Any(e => e.Name.Equals(name, StringComparison.OrdinalIgnoreCase)))
            {
                Debug.WriteLine($"[NestEngineRegistry] Duplicate engine '{name}' skipped");
                return;
            }

            engines.Add(new NestEngineInfo(name, description, factory));
        }

        public static void LoadPlugins(string directory)
        {
            if (!Directory.Exists(directory))
                return;

            foreach (var dll in Directory.GetFiles(directory, "*.dll"))
            {
                try
                {
                    var assembly = Assembly.LoadFrom(dll);

                    foreach (var type in assembly.GetTypes())
                    {
                        if (type.IsAbstract || !typeof(NestEngineBase).IsAssignableFrom(type))
                            continue;

                        var ctor = type.GetConstructor(new[] { typeof(Plate) });

                        if (ctor == null)
                        {
                            Debug.WriteLine($"[NestEngineRegistry] Skipping {type.Name}: no Plate constructor");
                            continue;
                        }

                        // Create a temporary instance to read Name and Description.
                        try
                        {
                            var tempPlate = new Plate();
                            var instance = (NestEngineBase)ctor.Invoke(new object[] { tempPlate });
                            Register(instance.Name, instance.Description,
                                plate => (NestEngineBase)ctor.Invoke(new object[] { plate }));
                            Debug.WriteLine($"[NestEngineRegistry] Loaded plugin engine: {instance.Name}");
                        }
                        catch (Exception ex)
                        {
                            Debug.WriteLine($"[NestEngineRegistry] Failed to instantiate {type.Name}: {ex.Message}");
                        }
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine($"[NestEngineRegistry] Failed to load assembly {Path.GetFileName(dll)}: {ex.Message}");
                }
            }
        }
    }
}

• Step 2: Build to verify

Run: dotnet build OpenNest.Engine/OpenNest.Engine.csproj Expected: Build succeeded

• Step 3: Commit

git add OpenNest.Engine/NestEngineRegistry.cs
git commit -m "feat: add NestEngineRegistry with built-in registration and plugin loading"

---

Chunk 3: Callsite Migration

Task 5: Migrate OpenNest.Mcp callsites

Files:

• Modify: OpenNest.Mcp/Tools/NestingTools.cs

Six new NestEngine(plate) calls become NestEngineRegistry.Create(plate). The PackArea call on line 276 changes signature since PackArea now returns List<Part> instead of mutating the plate.

• Step 1: Replace all NestEngine instantiations

In NestingTools.cs, replace all six occurrences of new NestEngine(plate) with NestEngineRegistry.Create(plate).

Lines to change:

• Line 37: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 73: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 114: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 176: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 255: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 275: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Step 2: Fix PackArea call in AutoNestPlate

The old code on line 276 was:

                engine.PackArea(workArea, packItems);

This used the old bool PackArea(Box, List<NestItem>) which mutated the plate. The new virtual method returns List<Part>. Use the convenience Pack-like pattern instead. Replace lines 274-277:

                var before = plate.Parts.Count;
                var engine = new NestEngine(plate);
                engine.PackArea(workArea, packItems);
                totalPlaced += plate.Parts.Count - before;

With:

                var engine = NestEngineRegistry.Create(plate);
                var packParts = engine.PackArea(workArea, packItems, null, CancellationToken.None);
                if (packParts.Count > 0)
                {
                    plate.Parts.AddRange(packParts);
                    totalPlaced += packParts.Count;
                }

• Step 3: Build OpenNest.Mcp

Run: dotnet build OpenNest.Mcp/OpenNest.Mcp.csproj Expected: Build succeeded

• Step 4: Commit

git add OpenNest.Mcp/Tools/NestingTools.cs
git commit -m "refactor: migrate NestingTools to NestEngineRegistry"

---

Task 6: Migrate OpenNest.Console callsites

Files:

• Modify: OpenNest.Console/Program.cs

Three new NestEngine(plate) calls. The PackArea call also needs the same signature update.

• Step 1: Replace NestEngine instantiations

In Program.cs, replace:

• Line 351: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 380: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Step 2: Fix PackArea call

Replace lines 370-372:

                var engine = new NestEngine(plate);
                var before = plate.Parts.Count;
                engine.PackArea(workArea, packItems);

With:

                var engine = NestEngineRegistry.Create(plate);
                var packParts = engine.PackArea(workArea, packItems, null, CancellationToken.None);
                plate.Parts.AddRange(packParts);

And update line 374-375 from:

                if (plate.Parts.Count > before)
                    success = true;

To:

                if (packParts.Count > 0)
                    success = true;

• Step 3: Build OpenNest.Console

Run: dotnet build OpenNest.Console/OpenNest.Console.csproj Expected: Build succeeded

• Step 4: Commit

git add OpenNest.Console/Program.cs
git commit -m "refactor: migrate Console Program to NestEngineRegistry"

---

Task 7: Migrate OpenNest WinForms callsites

Files:

• Modify: OpenNest/Actions/ActionFillArea.cs

• Modify: OpenNest/Controls/PlateView.cs

• Modify: OpenNest/Forms/MainForm.cs

• Step 1: Migrate ActionFillArea.cs

In ActionFillArea.cs, replace both new NestEngine(plateView.Plate) calls:

• Line 50: var engine = new NestEngine(plateView.Plate); → var engine = NestEngineRegistry.Create(plateView.Plate);

• Line 64: var engine = new NestEngine(plateView.Plate); → var engine = NestEngineRegistry.Create(plateView.Plate);

• Step 2: Migrate PlateView.cs

In PlateView.cs, replace:

• Line 836: var engine = new NestEngine(Plate); → var engine = NestEngineRegistry.Create(Plate);

• Step 3: Migrate MainForm.cs

In MainForm.cs, replace all three new NestEngine(plate) calls:

• Line 797: var engine = new NestEngine(plate) { PlateNumber = plateCount }; → var engine = NestEngineRegistry.Create(plate); engine.PlateNumber = plateCount;

• Line 829: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Line 965: var engine = new NestEngine(plate); → var engine = NestEngineRegistry.Create(plate);

• Step 4: Fix MainForm PackArea call

In MainForm.cs, the auto-nest pack phase (around line 829-832) uses the old PackArea signature. Replace:

                        var engine = new NestEngine(plate);
                        var partsBefore = plate.Parts.Count;
                        engine.PackArea(workArea, packItems);
                        var packed = plate.Parts.Count - partsBefore;

With:

                        var engine = NestEngineRegistry.Create(plate);
                        var packParts = engine.PackArea(workArea, packItems, null, CancellationToken.None);
                        plate.Parts.AddRange(packParts);
                        var packed = packParts.Count;

• Step 5: Add plugin loading at startup

In MainForm.cs, find where post-processors are loaded at startup (look for Posts directory loading) and add engine plugin loading nearby. Add after the existing plugin loading:

            var enginesDir = Path.Combine(Application.StartupPath, "Engines");
            NestEngineRegistry.LoadPlugins(enginesDir);

If there is no explicit post-processor loading call visible, add this to the MainForm constructor or Load event.

• Step 6: Build the full solution

Run: dotnet build OpenNest.sln Expected: Build succeeded with no errors

• Step 7: Commit

git add OpenNest/Actions/ActionFillArea.cs OpenNest/Controls/PlateView.cs OpenNest/Forms/MainForm.cs
git commit -m "refactor: migrate WinForms callsites to NestEngineRegistry"

---

Chunk 4: Verification and Cleanup

Task 8: Verify no remaining NestEngine references

Files:

• No changes expected — verification only

• Step 1: Search for stale references

Run: grep -rn "new NestEngine(" --include="*.cs" . Expected: Only BruteForceRunner.cs should have new DefaultNestEngine(. No new NestEngine( references should remain.

Also run: grep -rn "class NestEngine[^B]" --include="*.cs" . Expected: No matches (the old class NestEngine no longer exists).

• Step 2: Build and run smoke test

Run: dotnet build OpenNest.sln Expected: Build succeeded, 0 errors, 0 warnings related to NestEngine

• Step 3: Publish MCP server

Run: dotnet publish OpenNest.Mcp/OpenNest.Mcp.csproj -c Release -o "$USERPROFILE/.claude/mcp/OpenNest.Mcp" Expected: Publish succeeded

• Step 4: Commit if any fixes were needed

If any issues were found and fixed in previous steps, commit them now.

---

Task 9: Update CLAUDE.md architecture documentation

Files:

• Modify: CLAUDE.md

• Step 1: Update architecture section

Update the ### OpenNest.Engine section in CLAUDE.md to document the new engine hierarchy:

• NestEngineBase is the abstract base class
• DefaultNestEngine is the current multi-phase engine (formerly NestEngine)
• NestEngineRegistry manages available engines and the active selection
• NestEngineInfo holds engine metadata
• Plugin engines loaded from Engines/ directory

Also update any references to NestEngine that should now say DefaultNestEngine or NestEngineBase.

• Step 2: Build to verify no docs broke anything

Run: dotnet build OpenNest.sln Expected: Build succeeded

• Step 3: Commit

git add CLAUDE.md
git commit -m "docs: update CLAUDE.md for abstract nest engine architecture"