Add ChapterKind for front/back matter chapters

Chapters can now be marked FrontMatter/Body/BackMatter. Number stays
the manuscript sort key for every chapter; the author-facing display
number is now computed per-request as the chapter's ordinal among
Body chapters only, so a foreword or afterword no longer shifts the
numbering of the rest of the book. Surfaced through the API, agent
toolset, and import toolset.

src/Novelly.Api/Agent/NovelAgentToolset.cs

@@ -385,7 +385,12 @@ public class NovelAgentToolset(
             "list_chapters",
             "List the novel's chapters in manuscript order with beat and word counts.",
             new JsonSchemaBuilder().Build(),
-            async (novelId, _, ct) => (await chapters.ListAsync(novelId, ct)).Select(c => c.ToSummaryResponse()));
+            async (novelId, _, ct) =>
+            {
+                var list = await chapters.ListAsync(novelId, ct);
+                var displayNumbers = ChapterNumbering.DisplayNumbers(list);
+                return list.Select(c => c.ToSummaryResponse(displayNumbers.TryGetValue(c.Id, out var n) ? n : null));
+            });
 
         yield return new AgentTool(
             "get_chapter",
@@ -396,15 +401,25 @@ public class NovelAgentToolset(
             async (_, input, ct) =>
             {
                 var chapterId = JsonInput.RequiredGuid(input, "chapter_id");
-                return await OrNotFound(chapters.GetAsync(chapterId, ct), c => c.ToResponse(), "Chapter", chapterId);
+                var chapter = await chapters.GetAsync(chapterId, ct);
+                if (chapter is null)
+                {
+                    return new ToolNotFound("Chapter", chapterId);
+                }
+
+                var displayNumber = await chapters.DisplayNumberAsync(chapter, ct);
+                return chapter.ToResponse(displayNumber);
             });
 
         yield return new AgentTool(
             "create_chapter",
-            "Add a chapter. Its number is appended to the end of the manuscript unless you supply one.",
+            "Add a chapter. Its number is appended to the end of the manuscript unless you supply one. "
+            + "Front matter (foreword, introduction, prologue) and back matter (afterword, about the "
+            + "author) are labeled by title alone and do not count against the numbered chapters.",
             new JsonSchemaBuilder()
                 .Str("title", "Chapter title.", required: true)
-                .Int("number", "Position in the manuscript, 1-based.")
+                .Int("number", "Manuscript position, 1-based, counting front and back matter.")
+                .Enum("kind", "Front matter, a numbered body chapter, or back matter. Defaults to a body chapter.", System.Enum.GetNames<ChapterKind>())
                 .Str("summary", "What the chapter covers.")
                 .StringArray("locations", "Where and when the chapter takes place. Unknown locations are created.")
                 .Str("notes", "Anything else worth recording.")
@@ -413,26 +428,39 @@ public class NovelAgentToolset(
                 .Str("prose", "The chapter's drafted text, in markdown, if you are writing it now.")
                 .StringArray("tags", "Tags for cross-referencing. Replaces the existing tags.")
                 .Build(),
-            async (novelId, input, ct) => await OrNotFound(chapters.CreateAsync(novelId, new CreateChapterRequest(
+            async (novelId, input, ct) =>
+            {
+                var chapter = await chapters.CreateAsync(novelId, new CreateChapterRequest(
                     JsonInput.RequiredString(input, "title"),
                     JsonInput.Int(input, "number"),
+                    JsonInput.Enum<ChapterKind>(input, "kind") ?? ChapterKind.Body,
                     JsonInput.String(input, "summary"),
                     JsonInput.Strings(input, "locations"),
                     JsonInput.String(input, "notes"),
                     JsonInput.Enum<DraftStatus>(input, "status") ?? DraftStatus.Planned,
                     JsonInput.Int(input, "target_word_count"),
                     JsonInput.String(input, "prose"),
-                JsonInput.Strings(input, "tags")), ct), c => c.ToResponse(), "Novel", novelId));
+                    JsonInput.Strings(input, "tags")), ct);
+
+                if (chapter is null)
+                {
+                    return new ToolNotFound("Novel", novelId);
+                }
+
+                var displayNumber = await chapters.DisplayNumberAsync(chapter, ct);
+                return chapter.ToResponse(displayNumber);
+            });
 
         yield return new AgentTool(
             "update_chapter",
-            "Revise a chapter's title, number, summary, locations, notes, status or drafted "
+            "Revise a chapter's title, number, kind, summary, locations, notes, status or drafted "
             + "prose. Use 'prose' to write or replace the chapter's draft text in markdown; the "
             + "word count is recomputed automatically.",
             new JsonSchemaBuilder()
                 .Str("chapter_id", "Id of the chapter to update.", required: true)
                 .Str("title", "New title.")
-                .Int("number", "Position in the manuscript.")
+                .Int("number", "Manuscript position, 1-based, counting front and back matter.")
+                .Enum("kind", "Front matter, a numbered body chapter, or back matter.", System.Enum.GetNames<ChapterKind>())
                 .Str("summary", "What the chapter covers.")
                 .StringArray("locations", "Where and when the chapter takes place. Replaces the existing locations. Unknown locations are created.")
                 .Str("notes", "Anything else worth recording.")
@@ -444,18 +472,27 @@ public class NovelAgentToolset(
             async (_, input, ct) =>
             {
                 var chapterId = JsonInput.RequiredGuid(input, "chapter_id");
-                return await OrNotFound(chapters.UpdateAsync(
+                var chapter = await chapters.UpdateAsync(
                     chapterId,
                     new UpdateChapterRequest(
                         JsonInput.String(input, "title"),
                         JsonInput.Int(input, "number"),
+                        JsonInput.Enum<ChapterKind>(input, "kind"),
                         JsonInput.String(input, "summary"),
                         JsonInput.Strings(input, "locations"),
                         JsonInput.String(input, "notes"),
                         JsonInput.Enum<DraftStatus>(input, "status"),
                         JsonInput.Int(input, "target_word_count"),
                         JsonInput.String(input, "prose"),
-                        JsonInput.Strings(input, "tags")), ct), c => c.ToResponse(), "Chapter", chapterId);
+                        JsonInput.Strings(input, "tags")), ct);
+
+                if (chapter is null)
+                {
+                    return new ToolNotFound("Chapter", chapterId);
+                }
+
+                var displayNumber = await chapters.DisplayNumberAsync(chapter, ct);
+                return chapter.ToResponse(displayNumber);
             });
 
         yield return new AgentTool(

src/Novelly.Api/Chapters/Chapter.cs

@@ -16,6 +16,8 @@ public class Chapter
 
     public int Number { get; set; }
 
+    public ChapterKind Kind { get; set; } = ChapterKind.Body;
+
     public string Title { get; set; } = string.Empty;
 
     public string? Summary { get; set; }
@@ -44,6 +46,7 @@ public class ChapterEntityTypeConfiguration : IEntityTypeConfiguration<Chapter>
     {
         entity.Property(c => c.Title).IsRequired().HasMaxLength(300);
         entity.Property(c => c.Status).HasConversion<string>().HasMaxLength(32);
+        entity.Property(c => c.Kind).HasConversion<string>().HasMaxLength(32);
         entity.HasIndex(c => new { c.NovelId, c.Number });
     }
 }

src/Novelly.Api/Chapters/ChapterContracts.cs

@@ -10,6 +10,8 @@ public record ChapterSummaryResponse(
     Guid Id,
     Guid NovelId,
     int Number,
+    ChapterKind Kind,
+    int? DisplayNumber,
     string Title,
     string? Summary,
     IReadOnlyList<LocationResponse> Locations,
@@ -24,6 +26,8 @@ public record ChapterResponse(
     Guid Id,
     Guid NovelId,
     int Number,
+    ChapterKind Kind,
+    int? DisplayNumber,
     string Title,
     string? Summary,
     IReadOnlyList<LocationResponse> Locations,
@@ -39,6 +43,7 @@ public record ChapterResponse(
 public record CreateChapterRequest(
     string Title,
     int? Number = null,
+    ChapterKind Kind = ChapterKind.Body,
     string? Summary = null,
     IReadOnlyList<string>? Locations = null,
     string? Notes = null,
@@ -63,6 +68,7 @@ public class CreateChapterRequestValidator : IModelValidator<CreateChapterReques
 public record UpdateChapterRequest(
     string? Title = null,
     int? Number = null,
+    ChapterKind? Kind = null,
     string? Summary = null,
     IReadOnlyList<string>? Locations = null,
     string? Notes = null,
@@ -115,8 +121,8 @@ file static class ChapterValidation
 
 public static class ChapterMapping
 {
-    public static ChapterResponse ToResponse(this Chapter c) => new(
-        c.Id, c.NovelId, c.Number, c.Title, c.Summary,
+    public static ChapterResponse ToResponse(this Chapter c, int? displayNumber = null) => new(
+        c.Id, c.NovelId, c.Number, c.Kind, displayNumber, c.Title, c.Summary,
         [.. c.Locations.OrderBy(l => l.Name).Select(l => l.ToResponse())],
         c.Notes,
         c.Status, c.TargetWordCount,
@@ -125,8 +131,8 @@ public static class ChapterMapping
         [.. c.Tags.OrderBy(t => t.Name).Select(t => t.ToResponse())],
         c.UpdatedAt);
 
-    public static ChapterSummaryResponse ToSummaryResponse(this Chapter c) => new(
-        c.Id, c.NovelId, c.Number, c.Title, c.Summary,
+    public static ChapterSummaryResponse ToSummaryResponse(this Chapter c, int? displayNumber = null) => new(
+        c.Id, c.NovelId, c.Number, c.Kind, displayNumber, c.Title, c.Summary,
         [.. c.Locations.OrderBy(l => l.Name).Select(l => l.ToResponse())],
         c.Status, c.TargetWordCount,
         c.Beats.Count, c.WordCount,

src/Novelly.Api/Chapters/ChapterEndpoints.cs

@@ -12,7 +12,12 @@ public static class ChapterEndpoints
             .AddEndpointFilter<ValidationEndpointFilter>();
 
         novelScoped.MapGet("/", async (Guid novelId, ChapterService service, CancellationToken ct) =>
-                Results.Ok((await service.ListAsync(novelId, ct)).Select(c => c.ToSummaryResponse())))
+            {
+                var chapters = await service.ListAsync(novelId, ct);
+                var displayNumbers = ChapterNumbering.DisplayNumbers(chapters);
+                return Results.Ok(chapters.Select(c =>
+                    c.ToSummaryResponse(displayNumbers.TryGetValue(c.Id, out var n) ? n : null)));
+            })
             .WithSummary("List a novel's chapters in manuscript order.");
 
         novelScoped.MapPost("/", async (
@@ -24,7 +29,8 @@ public static class ChapterEndpoints
                     return Results.NotFound();
                 }
 
-                var created = chapter.ToResponse();
+                var displayNumber = await service.DisplayNumberAsync(chapter, ct);
+                var created = chapter.ToResponse(displayNumber);
                 return Results.Created($"/api/chapters/{created.Id}", created);
             })
             .WithSummary("Add a chapter.");
@@ -34,12 +40,30 @@ public static class ChapterEndpoints
             .AddEndpointFilter<ValidationEndpointFilter>();
 
         chapters.MapGet("/{id:guid}", async (Guid id, ChapterService service, CancellationToken ct) =>
-                (await service.GetAsync(id, ct))?.ToResponse().ToApiResult())
+            {
+                var chapter = await service.GetAsync(id, ct);
+                if (chapter is null)
+                {
+                    return Results.NotFound();
+                }
+
+                var displayNumber = await service.DisplayNumberAsync(chapter, ct);
+                return chapter.ToResponse(displayNumber).ToApiResult();
+            })
             .WithSummary("Read a chapter with its beats and prose.");
 
         chapters.MapPatch("/{id:guid}", async (
                 Guid id, UpdateChapterRequest request, ChapterService service, CancellationToken ct) =>
-                (await service.UpdateAsync(id, request, ct))?.ToResponse().ToApiResult())
+            {
+                var chapter = await service.UpdateAsync(id, request, ct);
+                if (chapter is null)
+                {
+                    return Results.NotFound();
+                }
+
+                var displayNumber = await service.DisplayNumberAsync(chapter, ct);
+                return chapter.ToResponse(displayNumber).ToApiResult();
+            })
             .WithSummary("Update a chapter.");
 
         chapters.MapDelete("/{id:guid}", async (Guid id, ChapterService service, CancellationToken ct) =>

src/Novelly.Api/Chapters/ChapterKind.cs

@@ -0,0 +1,8 @@
+namespace Novelly.Api.Chapters;
+
+public enum ChapterKind
+{
+    FrontMatter,
+    Body,
+    BackMatter
+}

src/Novelly.Api/Chapters/ChapterNumbering.cs

@@ -0,0 +1,25 @@
+namespace Novelly.Api.Chapters;
+
+public static class ChapterNumbering
+{
+    public static IReadOnlyDictionary<Guid, int> DisplayNumbers(IEnumerable<Chapter> novelChapters)
+    {
+        var displayNumbers = new Dictionary<Guid, int>();
+        var next = 1;
+
+        foreach (var chapter in novelChapters.OrderBy(c => c.Number))
+        {
+            if (chapter.Kind != ChapterKind.Body)
+                continue;
+
+            displayNumbers[chapter.Id] = next++;
+        }
+
+        return displayNumbers;
+    }
+
+    public static string Label(ChapterKind kind, int? displayNumber, string title) =>
+        kind == ChapterKind.Body && displayNumber is { } number
+            ? $"Chapter {number}: {title}"
+            : title;
+}

src/Novelly.Api/Chapters/ChapterService.cs

@@ -73,6 +73,7 @@ public class ChapterService(
             NovelId = novelId,
             Title = request.Title,
             Number = request.Number ?? await NextChapterNumberAsync(novelId, ct),
+            Kind = request.Kind,
             Summary = request.Summary,
             Notes = request.Notes,
             Status = request.Status,
@@ -116,6 +117,7 @@ public class ChapterService(
 
         chapter.Title = Patch.Apply(chapter.Title, request.Title) ?? chapter.Title;
         chapter.Number = request.Number ?? chapter.Number;
+        chapter.Kind = request.Kind ?? chapter.Kind;
         chapter.Summary = Patch.Apply(chapter.Summary, request.Summary);
         chapter.Notes = Patch.Apply(chapter.Notes, request.Notes);
         chapter.Status = request.Status ?? chapter.Status;
@@ -166,6 +168,15 @@ public class ChapterService(
         return true;
     }
 
+    public async Task<int?> DisplayNumberAsync(Chapter chapter, CancellationToken ct = default)
+    {
+        if (chapter.Kind != ChapterKind.Body)
+            return null;
+
+        return await db.Chapters.CountAsync(
+            c => c.NovelId == chapter.NovelId && c.Kind == ChapterKind.Body && c.Number <= chapter.Number, ct);
+    }
+
     private async Task<int> NextChapterNumberAsync(Guid novelId, CancellationToken ct)
     {
         logger.LogDebug("Computing next chapter number for novel {NovelId}", novelId);

src/Novelly.Api/Data/Migrations/20260820005308_AddChapterKind.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Novelly.Api.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddChapterKind : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "Kind",
+                table: "Chapters",
+                type: "TEXT",
+                maxLength: 32,
+                nullable: false,
+                defaultValue: "Body");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "Kind",
+                table: "Chapters");
+        }
+    }
+}

src/Novelly.Api/Data/Migrations/NovelDbContextModelSnapshot.cs

@@ -319,6 +319,11 @@ namespace Novelly.Api.Data.Migrations
                     b.Property<long>("CreatedAt")
                         .HasColumnType("INTEGER");
 
+                    b.Property<string>("Kind")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("TEXT");
+
                     b.Property<string>("Notes")
                         .HasColumnType("TEXT");
 

src/Novelly.Api/Imports/ImportAgentToolset.cs

@@ -274,10 +274,12 @@ public class ImportAgentToolset(
 
         yield return new ImportAgentTool(
             "create_chapter",
-            "Add a chapter. Its number is appended to the end of the manuscript unless you supply one.",
+            "Add a chapter. Its number is appended to the end of the manuscript unless you supply one. "
+            + "Use 'kind' for a foreword, prologue, afterword, or other unnumbered front/back matter.",
             new JsonSchemaBuilder()
                 .Str("title", "Chapter title.", required: true)
                 .Int("number", "Position in the manuscript, 1-based, matching the outline's chapter number.")
+                .Enum("kind", "Front matter, a numbered body chapter, or back matter. Defaults to a body chapter.", System.Enum.GetNames<ChapterKind>())
                 .Str("summary", "The chapter's prose summary paragraph(s).")
                 .Str("notes", "The chapter file's ## Notes section, if present.")
                 .StringArray("tags", "The Part value and the raw Thread text, e.g. ['Part I', 'thread:Logen'].")
@@ -288,6 +290,7 @@ public class ImportAgentToolset(
                 var created = await chapters.CreateAsync(novelId, new CreateChapterRequest(
                     JsonInput.RequiredString(input, "title"),
                     JsonInput.Int(input, "number"),
+                    JsonInput.Enum<ChapterKind>(input, "kind") ?? ChapterKind.Body,
                     JsonInput.String(input, "summary"),
                     Notes: JsonInput.String(input, "notes"),
                     Tags: JsonInput.Strings(input, "tags")), ct);

tests/Novelly.Api.Tests/ChapterServiceTests.cs

@@ -78,4 +78,62 @@ public class ChapterServiceTests : ServiceTestFixture
     [Test]
     public async Task Deleting_a_missing_chapter_returns_false_rather_than_throwing() =>
         Assert.That(await Chapters.DeleteAsync(Guid.NewGuid()), Is.False);
+
+    [Test]
+    public async Task A_chapter_defaults_to_a_body_chapter()
+    {
+        var chapter = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Landfall"));
+
+        Assert.That(chapter!.Kind, Is.EqualTo(ChapterKind.Body));
+    }
+
+    [Test]
+    public async Task Front_matter_does_not_consume_a_chapter_number()
+    {
+        var foreword = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Foreword", Number: 1, Kind: ChapterKind.FrontMatter));
+        var first = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Landfall", Number: 2));
+        var second = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("The Harbour", Number: 3));
+
+        var displayNumbers = ChapterNumbering.DisplayNumbers(await Chapters.ListAsync(_novelId));
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(displayNumbers.ContainsKey(foreword!.Id), Is.False);
+            Assert.That(displayNumbers[first!.Id], Is.EqualTo(1));
+            Assert.That(displayNumbers[second!.Id], Is.EqualTo(2));
+        });
+    }
+
+    [Test]
+    public async Task Back_matter_is_listed_last_but_carries_no_chapter_number()
+    {
+        var body = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Landfall", Number: 1));
+        var afterword = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Afterword", Number: 2, Kind: ChapterKind.BackMatter));
+
+        var afterwordDisplayNumber = await Chapters.DisplayNumberAsync(afterword!);
+        var bodyDisplayNumber = await Chapters.DisplayNumberAsync(body!);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(afterwordDisplayNumber, Is.Null);
+            Assert.That(bodyDisplayNumber, Is.EqualTo(1));
+        });
+    }
+
+    [Test]
+    public async Task Changing_a_chapter_to_front_matter_drops_it_from_the_chapter_count()
+    {
+        var chapter = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Prologue", Number: 1));
+        var other = await Chapters.CreateAsync(_novelId, new CreateChapterRequest("Landfall", Number: 2));
+
+        var updated = await Chapters.UpdateAsync(chapter!.Id, new UpdateChapterRequest(Kind: ChapterKind.FrontMatter));
+        var updatedDisplayNumber = await Chapters.DisplayNumberAsync(updated!);
+        var otherDisplayNumber = await Chapters.DisplayNumberAsync(other!);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(updatedDisplayNumber, Is.Null);
+            Assert.That(otherDisplayNumber, Is.EqualTo(1));
+        });
+    }
 }