feat(mcp): complete jobs with finite mixed sheet stock

OpenNest.FrontEnd.Tests/McpWholeJobTests.cs

@@ -15,13 +15,13 @@ public class McpWholeJobTests : IDisposable
     public McpWholeJobTests() => Directory.CreateDirectory(directory);
     public void Dispose() => Directory.Delete(directory, true);
 
-    private static Drawing Square(string name)
+    private static Drawing Square(string name, double size = 2)
     {
         var shape = new Shape();
-        shape.Entities.Add(new Line(new Vector(0, 0), new Vector(2, 0)));
-        shape.Entities.Add(new Line(new Vector(2, 0), new Vector(2, 2)));
-        shape.Entities.Add(new Line(new Vector(2, 2), new Vector(0, 2)));
-        shape.Entities.Add(new Line(new Vector(0, 2), new Vector(0, 0)));
+        shape.Entities.Add(new Line(new Vector(0, 0), new Vector(size, 0)));
+        shape.Entities.Add(new Line(new Vector(size, 0), new Vector(size, size)));
+        shape.Entities.Add(new Line(new Vector(size, size), new Vector(0, size)));
+        shape.Entities.Add(new Line(new Vector(0, size), new Vector(0, 0)));
         return new Drawing(name, OpenNest.Converters.ConvertGeometry.ToProgram(shape));
     }
 
@@ -38,6 +38,173 @@ public class McpWholeJobTests : IDisposable
         string engine, bool noNew = false, CancellationToken token = default) =>
         tools.AutoNestJob(plateIndex, names, quantities, engine, noNew, token);
 
+    [Fact]
+    public void FiniteSheetInputsReachEngineWithTemplateSettings()
+    {
+        var session = Session();
+        var template = session.GetPlate(0);
+        template.Size = new Size(60, 120);
+        template.EdgeSpacing = new Spacing(1, 2, 3, 4);
+        template.Quadrant = 3;
+        var engine = "StockMap-" + Guid.NewGuid();
+        var called = false;
+        NestingEngineRegistry.Register(engine, "inspect finite stock", () => new InspectStub(job =>
+        {
+            called = true;
+            Assert.Equal(2, job.Plates.Count);
+            Assert.Equal(["stock-0", "stock-1"], job.Plates.Select(s => s.Id));
+            Assert.Equal([new Size(60, 120), new Size(48, 96)], job.Plates.Select(s => s.Size));
+            Assert.Equal([1, 2], job.Plates.Select(s => s.Quantity));
+            Assert.All(job.Plates, stock =>
+            {
+                Assert.Equal(0.25, stock.PartSpacing);
+                Assert.Equal(template.EdgeSpacing, stock.EdgeSpacing);
+                Assert.Equal(3, stock.Quadrant);
+            });
+            Assert.Equal(2, job.Options.MaxPlates); // capped by demand, not plate.Quantity
+            return new NestJobResult(NestJobStatus.Incomplete, NestJobStopReason.StockExhausted, [], [], []);
+        }));
+        var rows = new[] { new SheetStockInput { Width = 60, Length = 120, Quantity = 1 },
+            new SheetStockInput { Width = 48, Length = 96, Quantity = 2 } };
+        var tool = new NestingTools(session);
+        Assert.Contains("incomplete", tool.AutoNestJob(0, "A,B", "1,1", engine, sheets: rows));
+        Assert.True(called);
+        called = false;
+        rows[1].Width = double.NaN;
+        Assert.Contains("sheets[1]", tool.AutoNestJob(0, "A,B", "1,1", engine, sheets: rows));
+        Assert.False(called);
+        Assert.Single(session.AllPlates());
+        Assert.Empty(template.Parts);
+        Assert.Equal(1, template.Quantity); // no inventory drawn from the template quantity
+    }
+
+    private sealed class InspectStub(Func<NestJob, NestJobResult> solve) : INestingEngine
+    {
+        public NestJobResult Solve(NestJob job, IProgress<NestJobProgress>? progress = null,
+            CancellationToken token = default) => solve(job);
+    }
+
+    [Fact]
+    public void FiniteMixedSheetsCommitByStockIdAndRoundTrip()
+    {
+        var session = Session();
+        var template = session.GetPlate(0);
+        template.Size = new Size(6, 6);
+        template.Quantity = 9; // repeat count is not inventory
+        var small = session.Nest.Drawings.Single(d => d.Name == "B");
+        var large = Square("large", 4); // four-by-four cannot fit a three-by-three sheet
+        session.Nest.Drawings.Add(large);
+        var rows = new[] { new SheetStockInput { Width = 6, Length = 6, Quantity = 1 },
+            new SheetStockInput { Width = 3, Length = 3, Quantity = 2 } };
+        var engine = "MixedStock-" + Guid.NewGuid();
+        NestingEngineRegistry.Register(engine, "two different sheets", () => new InspectStub(job =>
+        {
+            Assert.Equal(2, job.Options.MaxPlates);
+            Assert.Equal([1, 2], job.Plates.Select(s => s.Quantity));
+            // Small stock first: result ordinal must not resize/reuse the large template.
+            return new NestJobResult(NestJobStatus.Complete, NestJobStopReason.Completed,
+                [new NestJobPlateResult(0, job.Plates[1], [new NestJobPlacement(job.Parts[1].Id, 0, 0.5, 0.5, 0)]),
+                 new NestJobPlateResult(1, job.Plates[0], [new NestJobPlacement(job.Parts[0].Id, 1, 0.5, 0.5, 0)])], [], []);
+        }));
+        var text = new NestingTools(session).AutoNestJob(0, "large,B", "1,1", engine, sheets: rows);
+        Assert.Contains("Whole job complete", text);
+        Assert.Contains("stock-0 (6x6): used=1, remaining=0, reused=1, created=0", text);
+        Assert.Contains("stock-1 (3x3): used=1, remaining=1, reused=0, created=1", text);
+        Assert.Contains("plate 0 -> stock-0", text);
+        Assert.Contains("plate 1 -> stock-1", text);
+        Assert.Same(template, session.GetPlate(0));
+        Assert.Equal(new Size(6, 6), template.Size);
+        Assert.Same(large, Assert.Single(template.Parts).BaseDrawing);
+        Assert.Same(small, Assert.Single(session.GetPlate(1).Parts).BaseDrawing);
+        Assert.Equal(1, template.Quantity);
+        var path = Path.Combine(directory, "mixed.nest");
+        Assert.Contains("Saved nest", new InputTools(session).SaveNest(path));
+        var reloaded = new NestReader(path).Read();
+        Assert.Equal([new Size(6, 6), new Size(3, 3)], reloaded.Plates.Select(p => p.Size));
+        Assert.All(reloaded.Plates, p => Assert.Equal(1, p.Quantity));
+        Assert.Equal(1, reloaded.Drawings.Single(d => d.Name == "large").Quantity.Nested);
+        Assert.Equal(1, reloaded.Drawings.Single(d => d.Name == "B").Quantity.Nested);
+    }
+
+    [Fact]
+    public void FiniteStockOverdrawIsRejectedBeforeAnySessionMutation()
+    {
+        var session = Session();
+        var plate = session.GetPlate(0);
+        plate.Size = new Size(3, 3);
+        var engine = "Overdraw-" + Guid.NewGuid();
+        NestingEngineRegistry.Register(engine, "overdraw stock", () => new InspectStub(job =>
+            new NestJobResult(NestJobStatus.Complete, NestJobStopReason.Completed,
+                [new NestJobPlateResult(0, job.Plates[0], [new NestJobPlacement(job.Parts[0].Id, 0, 0.5, 0.5, 0)]),
+                 new NestJobPlateResult(1, job.Plates[0], [new NestJobPlacement(job.Parts[1].Id, 1, 0.5, 0.5, 0)])], [], [])));
+        var text = new NestingTools(session).AutoNestJob(0, "A,B", "1,1", engine,
+            sheets: [new SheetStockInput { Width = 3, Length = 3, Quantity = 1 },
+                new SheetStockInput { Width = 6, Length = 6, Quantity = 2 }]);
+        Assert.Contains("stock-0", text);
+        Assert.Contains("invalid", text, StringComparison.OrdinalIgnoreCase);
+        Assert.Single(session.AllPlates());
+        Assert.Empty(plate.Parts);
+        Assert.All(session.Nest.Drawings, d => Assert.Equal(0, d.Quantity.Nested));
+    }
+
+    [Fact]
+    public void FiniteStockRejectsInvalidInventoryBeforeSolving()
+    {
+        var session = Session();
+        var plate = session.GetPlate(0);
+        var engine = "NeverSolve-" + Guid.NewGuid();
+        NestingEngineRegistry.Register(engine, "should not be called", () => new InspectStub(_ =>
+            throw new Xunit.Sdk.XunitException("invalid input reached solver")));
+        var tools = new NestingTools(session);
+        var valid = new SheetStockInput { Width = 10, Length = 10, Quantity = 1 };
+        Assert.Contains("at least one", tools.AutoNestJob(0, "A", "1", engine, sheets: []));
+        Assert.Contains("sheets[0]", tools.AutoNestJob(0, "A", "1", engine,
+            sheets: [new SheetStockInput { Width = 10, Length = 10, Quantity = 0 }]));
+        Assert.Contains("sheets[0]", tools.AutoNestJob(0, "A", "1", engine,
+            sheets: [new SheetStockInput { Width = double.PositiveInfinity, Length = 10, Quantity = 1 }]));
+        Assert.Contains("sheets[0]", tools.AutoNestJob(0, "A", "1", engine,
+            sheets: [new SheetStockInput { Width = 0, Length = 10, Quantity = 1 }]));
+        Assert.Contains("sheets[1] duplicates sheets[0]", tools.AutoNestJob(0, "A", "1", engine,
+            sheets: [valid, new SheetStockInput { Width = 10, Length = 10, Quantity = 2 }]));
+        Assert.Contains("sheet inventory exceeds", tools.AutoNestJob(0, "A", "1", engine,
+            sheets: [new SheetStockInput { Width = 10, Length = 10, Quantity = int.MaxValue },
+                new SheetStockInput { Width = 11, Length = 11, Quantity = 1 }]));
+        Assert.Contains("cannot be combined", tools.AutoNestJob(0, "A", "1", engine,
+            no_new_plates: true, sheets: [valid]));
+        Assert.Single(session.AllPlates());
+        Assert.Empty(plate.Parts);
+        Assert.Equal(1, plate.Quantity);
+    }
+
+    [Fact]
+    public void FiniteInventoryUsesOnlyOneOfTwoMatchingEmptySheets()
+    {
+        var session = Session();
+        var original = session.GetPlate(0);
+        session.Plates.Add(new Plate(10, 10) { PartSpacing = 0.25, Quantity = 5 });
+        var text = new NestingTools(session).AutoNestJob(0, "A", "1", "Rectangles",
+            sheets: [new SheetStockInput { Width = 10, Length = 10, Quantity = 1 }]);
+        Assert.Contains("Whole job complete", text);
+        Assert.Contains("stock-0 (10x10): used=1, remaining=0", text);
+        Assert.Single(original.Parts);
+        Assert.Empty(session.GetPlate(1).Parts);
+        Assert.Equal(5, session.GetPlate(1).Quantity);
+    }
+
+    [Fact]
+    public void LaterSelectedTemplateIsReusedBeforeOtherCompatibleEmptySheet()
+    {
+        var session = Session();
+        var earlier = session.GetPlate(0);
+        var selected = new Plate(10, 10) { PartSpacing = 0.25, Quantity = 3 };
+        session.Plates.Add(selected);
+        var text = new NestingTools(session).AutoNestJob(1, "A", "1", "Rectangles");
+        Assert.Contains("Whole job complete", text);
+        Assert.Empty(earlier.Parts);
+        Assert.Single(selected.Parts);
+        Assert.Equal(1, selected.Quantity);
+    }
+
     [Fact]
     public void CreatesSheetsForCompleteMixedJobThenSavesAndReloads()
     {

OpenNest.Mcp/SheetStockInput.cs

@@ -0,0 +1,9 @@
+namespace OpenNest.Mcp;
+
+/// <summary>Request-local physical inventory for one whole-job solve.</summary>
+public sealed class SheetStockInput
+{
+    public double Width { get; set; }
+    public double Length { get; set; }
+    public int Quantity { get; set; }
+}

OpenNest.Mcp/Tools/NestingTools.cs

@@ -336,14 +336,15 @@ namespace OpenNest.Mcp.Tools
         }
 
         [McpServerTool(Name = "autonest_job")]
-        [Description("Complete requested drawing quantities across as many matching sheets as needed. The selected empty plate is the stock template; by default new sheets may be added. An incomplete or invalid proposal changes nothing.")]
+        [Description("Complete requested drawing quantities across physical sheets. The selected empty plate supplies common settings; optional sheets offer finite sizes and quantities. An incomplete or invalid proposal changes nothing.")]
         public string AutoNestJob(
             [Description("Index of an empty plate to use as the stock template")] int plateIndex,
             [Description("Comma-separated drawing names")] string drawingNames,
             [Description("Comma-separated total requested quantities for the entire session")] string quantities,
             [Description(JobEngines)] string engine = null,
             [Description("Use only already-created empty plates with matching dimensions and spacing; do not add sheets")] bool no_new_plates = false,
-            CancellationToken cancellationToken = default
+            CancellationToken cancellationToken = default,
+            [Description("Optional finite physical sheet stock: width, length and available quantity per size. Incompatible with no_new_plates.")] SheetStockInput[] sheets = null
         )
         {
             var template = _session.GetPlate(plateIndex);
@@ -351,6 +352,11 @@ namespace OpenNest.Mcp.Tools
                 return $"Error: plate {plateIndex} not found";
             if (template.Parts.Count != 0 || template.CutOffs.Count != 0)
                 return "Error: stock template must be empty and have no cutoff definitions. Nothing committed.";
+            if (sheets != null && no_new_plates)
+                return "Error: sheets cannot be combined with no_new_plates. Nothing committed.";
+            var offeredStock = BuildSheetStock(template, sheets);
+            if (offeredStock.error != null)
+                return offeredStock.error;
             if (string.IsNullOrWhiteSpace(drawingNames) || string.IsNullOrWhiteSpace(quantities))
                 return "Error: drawingNames and quantities are required";
             var parsed = ParseItems(drawingNames, quantities);
@@ -390,7 +396,8 @@ namespace OpenNest.Mcp.Tools
             var demand = remaining.Sum(item => (long)item.Quantity);
             if (demand > int.MaxValue)
                 return "Error: total remaining demand exceeds the supported sheet limit. Nothing committed.";
-            var limit = no_new_plates ? System.Math.Min(available.Count, (int)demand) : (int)demand;
+            var limit = no_new_plates ? System.Math.Min(available.Count, (int)demand)
+                : sheets != null ? (int)System.Math.Min(offeredStock.total, demand) : (int)demand;
             var engineName = string.IsNullOrWhiteSpace(engine) ? _session.DefaultEngineName : engine.Trim();
             if (NestingEngineRegistry.ResolveName(engineName) == null)
                 return $"Error: unknown whole-job engine '{engineName}'. Nothing committed. Available: {string.Join(", ", NestingEngineRegistry.AvailableEngines.Select(e => e.Name))}";
@@ -398,7 +405,7 @@ namespace OpenNest.Mcp.Tools
             try
             {
                 result = NestPipeline.Run(new NestPipelineRequest(engineName, remaining,
-                    NestStockBuilder.FromTemplate(template, null, no_new_plates ? available.Count : null),
+                    sheets == null ? NestStockBuilder.FromTemplate(template, null, no_new_plates ? available.Count : null) : offeredStock.stock,
                     new NestJobOptions(maxPlates: limit)), token: cancellationToken);
             }
             catch (NotSupportedException ex)
@@ -422,33 +429,88 @@ namespace OpenNest.Mcp.Tools
             if (result.Plates.Count > limit)
                 return "Error: proposal exceeds the allowed sheet count. Nothing committed.";
 
-            cancellationToken.ThrowIfCancellationRequested();
-            for (var i = 0; i < result.Plates.Count; i++)
+            // Build the entire target map before attaching a single part. Indexes in a mixed
+            // stock proposal are solver ordinals, not indexes into the session's empty plates.
+            var usedTargets = new HashSet<Plate>(ReferenceEqualityComparer.Instance);
+            var targets = new List<(Plate plate, bool created, string stockId)>();
+            foreach (var proposed in result.Plates)
             {
-                var proposed = result.Plates[i];
-                var target = i < available.Count ? available[i] : new Plate(proposed.Stock.Size)
+                var target = new[] { template }.Concat(existing.Where(p => !ReferenceEquals(p, template)))
+                    .FirstOrDefault(p => !usedTargets.Contains(p)
+                        && p.Parts.Count == 0 && p.CutOffs.Count == 0
+                        && SameStock(p, template, proposed.Stock.Size));
+                var created = target == null;
+                target ??= new Plate(proposed.Stock.Size)
                 {
                     GrainAngle = template.GrainAngle,
                     CuttingParameters = template.CuttingParameters,
                 };
+                usedTargets.Add(target);
+                targets.Add((target, created, proposed.Stock.Id));
+            }
+            cancellationToken.ThrowIfCancellationRequested();
+            for (var i = 0; i < result.Plates.Count; i++)
+            {
+                var proposed = result.Plates[i];
+                var (target, created, _) = targets[i];
                 target.Size = proposed.Stock.Size;
                 target.PartSpacing = proposed.Stock.PartSpacing;
                 target.EdgeSpacing = proposed.Stock.EdgeSpacing;
                 target.Quadrant = proposed.Stock.Quadrant;
                 target.Quantity = 1;
-                if (i >= available.Count)
+                if (created)
                     _session.Plates.Add(target);
                 target.Parts.AddRange(proposed.Parts);
             }
             var lines = new StringBuilder();
-            lines.AppendLine($"Whole job complete: {result.Plates.Count} sheet(s) placed, {System.Math.Max(0, result.Plates.Count - available.Count)} new sheet(s) created.");
+            lines.AppendLine($"Whole job complete: {result.Plates.Count} sheet(s) placed, {targets.Count(t => t.created)} new sheet(s) created.");
+            if (sheets != null)
+            {
+                foreach (var stock in offeredStock.stock)
+                {
+                    var used = targets.Count(t => t.stockId == stock.Id);
+                    lines.AppendLine($"  {stock.Id} ({stock.Size.Width}x{stock.Size.Length}): used={used}, remaining={stock.Quantity - used}, reused={targets.Count(t => !t.created && t.stockId == stock.Id)}, created={targets.Count(t => t.created && t.stockId == stock.Id)}");
+                }
+                foreach (var (target, _, stockId) in targets)
+                    lines.AppendLine($"  plate {_session.AllPlates().FindIndex(p => ReferenceEquals(p, target))} -> {stockId}");
+            }
             foreach (var item in parsed.items)
                 lines.AppendLine($"  {item.Drawing.Name}: requested={item.Quantity}, already={counts[item.Drawing]}, newly placed={placed.GetValueOrDefault(item.Drawing)}, remaining=0");
             return lines.ToString();
         }
 
-        private static bool SameStock(Plate a, Plate b) =>
-            a.Size.Width == b.Size.Width && a.Size.Length == b.Size.Length
+        private static (List<NestPlateStock> stock, long total, string error) BuildSheetStock(Plate template, SheetStockInput[] sheets)
+        {
+            if (sheets == null)
+                return (null, 0, null);
+            if (sheets.Length == 0)
+                return (null, 0, "Error: sheets must contain at least one stock size. Nothing committed.");
+            var stock = new List<NestPlateStock>(sheets.Length);
+            long total = 0;
+            for (var i = 0; i < sheets.Length; i++)
+            {
+                var row = sheets[i];
+                if (row == null || !double.IsFinite(row.Width) || !double.IsFinite(row.Length)
+                    || row.Width <= 0 || row.Length <= 0 || row.Quantity <= 0
+                    || row.Length <= template.EdgeSpacing.Left + template.EdgeSpacing.Right
+                    || row.Width <= template.EdgeSpacing.Top + template.EdgeSpacing.Bottom)
+                    return (null, 0, $"Error: sheets[{i}] requires finite positive usable dimensions and a positive physical quantity. Nothing committed.");
+                var duplicate = stock.FindIndex(s => s.Size.Width == row.Width && s.Size.Length == row.Length);
+                if (duplicate >= 0)
+                    return (null, 0, $"Error: sheets[{i}] duplicates sheets[{duplicate}] size. Nothing committed.");
+                total += row.Quantity;
+                if (total > int.MaxValue)
+                    return (null, 0, "Error: total sheet inventory exceeds the supported sheet limit. Nothing committed.");
+                stock.Add(new NestPlateStock($"stock-{i}", new Size(row.Width, row.Length), row.Quantity,
+                    template.PartSpacing, template.EdgeSpacing, template.Quadrant));
+            }
+            return (stock, total, null);
+        }
+
+        private static bool SameStock(Plate a, Plate b) => SameStock(a, b, b.Size);
+
+        private static bool SameStock(Plate a, Plate b, Size size) =>
+            a.Size.Width == size.Width && a.Size.Length == size.Length
             && a.PartSpacing == b.PartSpacing && a.EdgeSpacing.Equals(b.EdgeSpacing)
             && a.Quadrant == b.Quadrant && a.GrainAngle == b.GrainAngle
             && (a.CuttingParameters == null && b.CuttingParameters == null

docs/automatic-nesting.md

@@ -50,7 +50,9 @@ MCP `autonest_plate` requires an empty target. The stdio server serializes all t
 
 MCP `pack_plate` and `autonest_plate` report each requested drawing's newly placed count and remaining quantity, indexed by request; partial fulfillment is explicitly warned about. Per-sheet ratios are not enforced or required: an uneven sheet is acceptable if the remaining quantities are placed elsewhere in the nest. These two plate tools operate on a single selected plate and do not automatically finish a multi-sheet job; callers can use `autonest_job` for that. Duplicate request tokens and ambiguous drawing names are refused before placement. A zero-quantity pack request places zero parts for that drawing; negative quantities are rejected.
 
-`autonest_job(plateIndex, drawingNames, quantities, engine?, no_new_plates=false)` is the whole-session completion path. Quantities are total targets across existing placed parts (physical plate quantity included) plus newly proposed sheets. The selected empty cutoff-free plate supplies stock size, spacing, quadrant, grain and cutting settings; other empty plates with equivalent persisted settings may be reused first, then additional matching plates are created as needed. `no_new_plates=true` limits the solve to existing matching empty plates. The request uses the independently validated `NestPipeline` and commits only when every requested quantity is met; invalid, incomplete, cancelled or unknown-engine proposals leave existing plates and counts unchanged. A no-placement solver result is not proof that geometry cannot fit. `pack_plate` and `autonest_plate` remain single-sheet operations.
+`autonest_job(plateIndex, drawingNames, quantities, engine?, no_new_plates=false, sheets?)` is the whole-session completion path. Quantities are total targets across existing placed parts (physical plate quantity included) plus newly proposed sheets. Without `sheets`, the selected empty cutoff-free plate supplies stock size, spacing, quadrant, grain and cutting settings; other empty plates with equivalent persisted settings may be reused first, then additional matching plates are created as needed. `no_new_plates=true` limits this legacy solve to existing matching empty plates. The request uses the independently validated `NestPipeline` and commits only when every requested quantity is met; invalid, incomplete, cancelled or unknown-engine proposals leave existing plates and counts unchanged. A no-placement solver result is not proof that geometry cannot fit. `pack_plate` and `autonest_plate` remain single-sheet operations.
+
+For finite mixed-size inventory, supply `sheets` as an array, for example `{"plateIndex":0,"drawingNames":"large,small","quantities":"1,1","engine":"Rectangles","sheets":[{"width":60,"length":120,"quantity":1},{"width":48,"length":96,"quantity":2}]}`. Width and length have the same units and orientation as `create_plate`. Every row's positive integer `quantity` is the total physical sheets available for this solve, including any compatible pre-created empty plates; it is never a `Plate.Quantity` repeat multiplier or additional stock. The selected plate supplies common spacing, edge spacing, quadrant, grain and cutting settings, but is reused only if its size matches a chosen sheet. Other compatible empty sheets can be reused; occupied or cutoff-bearing sheets cannot. Only needed different-sized sheets are created. Duplicate size pairs, nonpositive or nonfinite dimensions, unusable work areas, nonpositive quantities, an empty list and excessive total inventory are refused before solving. `sheets` cannot be combined with `no_new_plates=true`. Omit `sheets` to retain the previous single-size behavior. Successful output reports `stock-0`, `stock-1`, etc. in input order with used/remaining/reused/created physical counts, plus committed session plate index to stock ID and per-drawing totals. Stock is request-local, not a persistent purchasing catalog. Unused empty templates may be omitted by the `.nest` writer on save.
 
 MCP `delete_plate(plateIndex)` removes only a sheet with no parts and no cutoff definitions, from either loaded or newly created session plates. Occupied, cutoff-bearing and invalid indices are refused without changing the session. After deletion every later index shifts down by one; inspect `get_plate_info` before further edits. This is session cleanup, not a data purge or a save-time option. `save_nest` lists all session plates in its response, but the existing `.nest` writer omits empty cutoff-free plates from the serialized file; reloading may therefore have fewer plates than the response says. There is no opt-in switch to preserve empty plates in the file.