feat: Add zero-alloc interpolation handler to ValueStringBuilder, replace all StringBuilder usage (#2387)

## Summary

- **Add a self-referencing `InterpolationHandler` to `ValueStringBuilder`** that writes directly into the builder's buffer — zero intermediate allocation, works with `stackalloc`-backed builders
- **Replace all `System.Text.StringBuilder` usage** across the codebase with `ValueStringBuilder`
- **Convert `ValueStringBuilder.Create()` to `stackalloc`** at 10 sites where output length is provably bounded
- **Convert manual `Dispose()` to `using var`** where possible, and hoist loop-scoped builders outside loops with `Reset()`
- **Convert verbose `Append()` chains to `Append($"...")`** interpolation for readability
- **Add comprehensive documentation** for string handling patterns

## InterpolationHandler Design

`ValueStringBuilder` is a `ref struct`, which creates challenges for C#'s interpolated string handler pattern:

- **`ref` fields to ref structs are not allowed** (CS9050)
- **`[InterpolatedStringHandlerArgument("")]` passes struct receivers by value**, not by ref
- **`ISelfInterpolatedStringHandler` requires boxing** ref structs into interface fields

**Solution: Copy-and-reconcile pattern.** The handler receives a value copy of the builder. The copy shares the same underlying `char` buffer (`Span` points to the same `stackalloc`/pooled memory), so writes go to the original buffer. `Append()` reconciles by `this = handler._builder`, updating `_length` and any buffer references changed by `Grow()`.

This is safe because:
- The game loop is single-threaded — no concurrent access between handler construction and reconciliation
- If `Grow()` occurs in the copy, the original's stale buffer isn't accessed until `Append()` replaces it
- `Dispose()` correctly returns the reconciled buffer to the pool

## Changes by Category

### ValueStringBuilder (`Projects/Server/Buffers/ValueStringBuilder.cs`)
- Added nested `InterpolationHandler` ref struct with copy-and-reconcile pattern
- Added `Append([InterpolatedStringHandlerArgument("")] scoped ref InterpolationHandler)` method
- Removed `RawInterpolatedStringHandler` overloads (new handler replaces them)
- All `AppendFormatted` overloads delegate to existing `Append` methods (no code duplication)
- Alignment support via direct private field access (nested type privilege)

### StringBuilder → ValueStringBuilder (15 files)
Replaced all `new StringBuilder()` with `ValueStringBuilder.Create()` or `stackalloc`:
- ConPVP games: KingOfTheHill, DoubleDom, CTF, BombingRun, TourneyMatch
- ConPVP infrastructure: Tournament, Participant, TourneyParticipant
- ConPVP gumps: ArenaGump, TournamentBracketGump, AcceptTeamGump, ConfirmSignupGump
- Commands: Handlers, Logging, Add
- Other: TownCrier, SpeechLogGump, TestCenter

Key patterns:
- `sb = new StringBuilder()` reassignment → `sb.Reset()`
- `sb.AppendFormat("{0:N0}", value)` → `sb.Append($"{value:N0}")`
- `sb.Append(x).Append(y)` chains → separate statements (VSB returns void)

### Create() → stackalloc (10 files)
Converted heap-allocated builders to stackalloc where output is bounded:
- ClientVersion (32), MapSelection (160), HouseRaffleStone (48)
- HolySense (96), UnholySense (96), ClientVerification (192)
- AcceptTeamGump (64), ConfirmSignupGump (64)
- BaseWeapon (160), BaseArmor (128)

### Loop optimizations (2 files)
Hoisted `ValueStringBuilder` creation outside loops with `Reset()` per iteration:
- TourneyMatch.cs: `using var` inside for loop → stackalloc before loop
- ArenaGump.cs: `Create()` + `Dispose()` per iteration → stackalloc before loop

### Append chain → interpolation (5 files)
Converted multi-line `Append()` chains to `Append($"...")`:
- BountyMessage.cs: title switch (6 cases), paragraph (15→1 Append), description lines, closing
- AcceptTeamGump, ConfirmSignupGump, TournamentBracketGump: tournament type strings
- AdminGump: comment/tag formatting in loops

### Documentation
- `dev-docs/string-handling.md`: Full reference — construction, interpolation, disposal, decision guide
- `dev-docs/claude-skills/modernuo-string-handling.md`: Claude skill with quick reference
- `CLAUDE.md`: Added rule 17 (no StringBuilder), dev-docs table entry, skills table entry
- `dev-docs/code-standards.md`: Updated memory management section

## Test Plan

- [x] `dotnet build` — 0 errors, 0 warnings
- [x] `dotnet test` — 940/940 tests pass
- [x] 28 ValueStringBuilder tests covering all reconciliation scenarios:
  - Stackalloc no-grow, stackalloc with grow (→pool transition)
  - Heap no-grow, heap with grow, heap double grow
  - Pre-existing content with and without grow
  - Sequential multiple `Append($"...")` calls
  - Mixed plain + interpolated Append
  - Empty interpolation, literal-only, format specifiers
  - Null string holes, ISpanFormattable types
  - Dispose after stackalloc→pool grow

CLAUDE.md

@@ -26,6 +26,7 @@ Apply these when writing or reviewing `.cs` files under `Projects/`.
 14. **PropertyList string literals must be holes** — `$"{"Map"}\t{value}"` not `$"Map\t{value}"`. The handler treats bare text as delimiters, `{}` holes as arguments. Only `\t` should be a bare literal → `dev-docs/property-lists.md`
 15. **Braces required on all control flow** — `if`, `else`, `for`, `foreach`, `while`, `do`, `switch` must always have braces, even for single-line bodies → `dev-docs/code-standards.md`
 16. **Prefer switch expressions and switch-when** — use switch expressions for value mapping and switch-when for pattern matching where they improve readability. Exception: skip if unreadable or cold path → `dev-docs/code-standards.md`
+17. **No `System.Text.StringBuilder`** — use `ValueStringBuilder` with `stackalloc` (bounded output) or `ValueStringBuilder.Create()` (unbounded). Supports `$"..."` interpolation directly. Always use `using var` for disposal. Use `Reset()` instead of reassigning → `dev-docs/string-handling.md`
 
 ## Dev-Docs Reference
 
@@ -45,6 +46,7 @@ Apply these when writing or reviewing `.cs` files under `Projects/`.
 | Configuration system | `dev-docs/configuration.md` |
 | Networking & packets | `dev-docs/networking-packets.md` |
 | Region system | `dev-docs/regions.md` |
+| String handling & ValueStringBuilder | `dev-docs/string-handling.md` |
 | RunUO migration (overview) | `dev-docs/runuo-migration-docs/00-overview.md` |
 | RunUO migration (all docs) | `dev-docs/runuo-migration-docs/` |
 
@@ -73,6 +75,7 @@ Then copy only the relevant skill files based on the task:
 | Timer work | `modernuo-timers`, `modernuo-serialization` |
 | Config system | `modernuo-configuration` |
 | Era-conditional code | `modernuo-era-expansion` |
+| String building / formatting | `modernuo-string-handling` |
 | Code review / audit | `modernuo-code-audit` |
 | Any `.cs` file edit | `modernuo-code-audit` (always offer for code changes) |
 | **RunUO Migration** | |

Projects/Server.Tests/Tests/Buffers/ValueStringBuilderTests.cs

@@ -46,4 +46,249 @@ public class ValueStringBuilderTests
         Assert.Equal($"Hi, this is {value}. I am a string.", sb.ToString());
         sb.Dispose();
     }
+
+    // --- InterpolationHandler reconciliation tests ---
+    // These validate the copy-and-reconcile pattern: the handler receives a VALUE COPY of the builder,
+    // writes into the shared buffer, and Append() reconciles via `this = handler._builder`.
+    // Critical to detect if C# compiler codegen changes break this assumption.
+
+    [Fact]
+    public void Interpolation_Stackalloc_NoGrow()
+    {
+        // Stackalloc buffer large enough — no Grow needed.
+        // Validates: copy's Span shares same stackalloc memory, _length is reconciled.
+        var sb = new ValueStringBuilder(stackalloc char[64]);
+        sb.Append($"Hello {42} world");
+
+        Assert.Equal("Hello 42 world", sb.ToString());
+        Assert.Equal(14, sb.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Stackalloc_WithGrow()
+    {
+        // Tiny stackalloc forces Grow inside the handler's copy.
+        // Validates: after Grow, copy moves to pooled array; reconciliation updates
+        // _chars, _arrayToReturnToPool, and _length on the original.
+        var sb = new ValueStringBuilder(stackalloc char[4]);
+        sb.Append($"This string is much longer than 4 chars: {12345}");
+
+        var expected = "This string is much longer than 4 chars: 12345";
+        Assert.Equal(expected, sb.ToString());
+        Assert.Equal(expected.Length, sb.Length);
+        // After grow, capacity should have expanded beyond 4
+        Assert.True(sb.Capacity >= 47);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Stackalloc_PreExistingContent_NoGrow()
+    {
+        // Append plain text first, then interpolation. Buffer large enough.
+        // Validates: interpolation appends after existing content, doesn't overwrite.
+        var sb = new ValueStringBuilder(stackalloc char[64]);
+        sb.Append("prefix-");
+        sb.Append($"value={99}");
+
+        Assert.Equal("prefix-value=99", sb.ToString());
+        Assert.Equal(15, sb.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Stackalloc_PreExistingContent_WithGrow()
+    {
+        // Fill most of a small stackalloc, then interpolate enough to force Grow.
+        // Validates: existing content is preserved through the Grow, new content is appended.
+        var sb = new ValueStringBuilder(stackalloc char[16]);
+        sb.Append("0123456789"); // 10 chars, 6 remaining
+        sb.Append($"abcdefghij{42}"); // 12 chars, exceeds remaining — Grow
+
+        Assert.Equal("0123456789abcdefghij42", sb.ToString());
+        Assert.Equal(22, sb.Length);
+        Assert.True(sb.Capacity >= 22);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Heap_NoGrow()
+    {
+        // Heap-allocated (Create) with sufficient capacity.
+        // Validates: handler works with pooled backing, _length is reconciled.
+        var sb = ValueStringBuilder.Create(64);
+        sb.Append($"Score: {100}, Name: {"Test"}");
+
+        Assert.Equal("Score: 100, Name: Test", sb.ToString());
+        Assert.Equal(22, sb.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Heap_WithGrow()
+    {
+        // Small heap allocation forces Grow.
+        // Validates: after Grow, copy's new pooled array replaces original's
+        // (original's old array was returned to pool by copy's Grow).
+        var sb = ValueStringBuilder.Create(4);
+        sb.Append($"This exceeds the initial 4 char capacity: {67890}");
+
+        var expected = "This exceeds the initial 4 char capacity: 67890";
+        Assert.Equal(expected, sb.ToString());
+        Assert.Equal(expected.Length, sb.Length);
+        Assert.True(sb.Capacity >= expected.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Heap_PreExistingContent_WithGrow()
+    {
+        // Heap with pre-existing content, then Grow via interpolation.
+        // Validates: existing content preserved, pooled array properly transitioned.
+        var sb = ValueStringBuilder.Create(8);
+        sb.Append("ABCD");
+        sb.Append($"EFGHIJKLMNOP{42}");
+
+        Assert.Equal("ABCDEFGHIJKLMNOP42", sb.ToString());
+        Assert.Equal(18, sb.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Sequential_MultipleAppends()
+    {
+        // Multiple sequential Append($"...") calls.
+        // Validates: each reconciliation correctly advances _length, subsequent calls
+        // see the updated state from prior reconciliations.
+        var sb = new ValueStringBuilder(stackalloc char[128]);
+        sb.Append($"A={1}");
+        sb.Append($" B={2}");
+        sb.Append($" C={3}");
+        sb.Append($" D={4}");
+
+        var expected = "A=1 B=2 C=3 D=4";
+        Assert.Equal(expected, sb.ToString());
+        Assert.Equal(expected.Length, sb.Length);
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Sequential_GrowOnSecondAppend()
+    {
+        // First Append fits, second triggers Grow.
+        // Validates: reconciliation after first Append leaves builder in a state
+        // that the second Append (with Grow) works correctly.
+        var sb = new ValueStringBuilder(stackalloc char[16]);
+        sb.Append($"Fits: {1}"); // 7 chars, fits in 16
+        sb.Append($" - Now this is a much longer string that forces growth: {999}");
+
+        Assert.Equal("Fits: 1 - Now this is a much longer string that forces growth: 999", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_MixedAppendStyles()
+    {
+        // Mix plain Append with interpolated Append.
+        // Validates: reconciliation is compatible with non-interpolated Append calls.
+        var sb = new ValueStringBuilder(stackalloc char[64]);
+        sb.Append("plain-");
+        sb.Append($"interp={42}-");
+        sb.Append("plain2-");
+        sb.Append($"interp2={99}");
+
+        Assert.Equal("plain-interp=42-plain2-interp2=99", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_EmptyInterpolation()
+    {
+        // Empty interpolation expression.
+        // Validates: handler with zero holes still reconciles correctly.
+        var sb = new ValueStringBuilder(stackalloc char[32]);
+        sb.Append("before");
+        sb.Append($"");
+        sb.Append("after");
+
+        Assert.Equal("beforeafter", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_OnlyLiteral()
+    {
+        // Interpolation with no holes (just a literal).
+        // Validates: AppendLiteral-only path reconciles _length.
+        var sb = new ValueStringBuilder(stackalloc char[32]);
+        sb.Append($"just a literal");
+
+        Assert.Equal("just a literal", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_FormatSpecifiers()
+    {
+        // Format specifiers in interpolation holes.
+        // Validates: AppendFormatted<T> with format string works through handler.
+        var sb = new ValueStringBuilder(stackalloc char[64]);
+        sb.Append($"pi={3.14159:F2}, hex={255:X4}, date={new System.DateTime(2025, 1, 15):yyyy-MM-dd}");
+
+        Assert.Equal("pi=3.14, hex=00FF, date=2025-01-15", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_SpanFormattableTypes()
+    {
+        // Various ISpanFormattable types.
+        // Validates: int, double, DateTime all format directly via TryFormat (no ToString allocation).
+        var sb = new ValueStringBuilder(stackalloc char[64]);
+        sb.Append($"{42}{3.14}{true}");
+
+        Assert.Equal("423.14True", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_NullString()
+    {
+        // Null string in interpolation hole.
+        // Validates: AppendFormatted(string?) handles null without crash.
+        string? name = null;
+        var sb = new ValueStringBuilder(stackalloc char[32]);
+        sb.Append($"Name: {name}!");
+
+        Assert.Equal("Name: !", sb.ToString());
+        sb.Dispose();
+    }
+
+    [Fact]
+    public void Interpolation_Stackalloc_DisposeAfterGrow()
+    {
+        // After Grow moves stackalloc to pool, Dispose should return the pooled array.
+        // Validates: _arrayToReturnToPool is correctly reconciled so Dispose works.
+        var sb = new ValueStringBuilder(stackalloc char[4]);
+        sb.Append($"grow beyond stackalloc: {12345}");
+        // If _arrayToReturnToPool wasn't reconciled, Dispose would either
+        // not return the pooled array (leak) or return null (no-op when it shouldn't be).
+        sb.Dispose();
+        // No assertion needed — if _arrayToReturnToPool was wrong, pool corruption
+        // would surface as test failures elsewhere. The test passing = no crash.
+    }
+
+    [Fact]
+    public void Interpolation_Heap_DoubleGrow()
+    {
+        // Force two consecutive Grows via two interpolated appends on a tiny buffer.
+        // Validates: reconciliation after first Grow leaves builder in valid state
+        // for the second Grow to succeed.
+        var sb = ValueStringBuilder.Create(4);
+        sb.Append($"First grow: {"ABCDEFGHIJ"}"); // forces first grow
+        sb.Append($"Second grow: {"KLMNOPQRSTUVWXYZ0123456789"}"); // forces second grow
+
+        Assert.Equal("First grow: ABCDEFGHIJSecond grow: KLMNOPQRSTUVWXYZ0123456789", sb.ToString());
+        sb.Dispose();
+    }
 }

Projects/Server/Buffers/ValueStringBuilder.cs

@@ -210,15 +210,6 @@ public ref struct ValueStringBuilder
         }
     }
 
-    // Compiler generated
-    public void Append(ref RawInterpolatedStringHandler handler) => Append(handler.Text);
-
-    // Compiler generated
-    public void Append(
-        IFormatProvider? formatProvider,
-        [InterpolatedStringHandlerArgument("formatProvider")]
-        ref RawInterpolatedStringHandler handler
-    ) => Append(handler.Text);
 
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -463,4 +454,128 @@ public ref struct ValueStringBuilder
 
         _length -= length;
     }
+
+    // Copy-and-reconcile interpolation handler.
+    // The handler receives a VALUE COPY of the builder (C# limitation: [InterpolatedStringHandlerArgument("")]
+    // passes struct receivers by value). The copy shares the same underlying char buffer (Span points to
+    // the same stackalloc/pooled memory), so writes go to the original buffer. If Grow() happens, the copy
+    // gets a new buffer. Append() reconciles by copying the handler's state back to the original.
+    // Safe because the game loop is single-threaded — no concurrent access between handler construction
+    // and reconciliation.
+
+    public void Append(
+        [InterpolatedStringHandlerArgument("")]
+        scoped ref InterpolationHandler handler)
+    {
+        // Reconcile: the handler's copy has the updated _length (and possibly new buffer from Grow).
+        this = handler._builder;
+    }
+
+    [InterpolatedStringHandler]
+    public ref struct InterpolationHandler
+    {
+        internal ValueStringBuilder _builder;
+
+        public InterpolationHandler(int literalLength, int formattedCount, ValueStringBuilder builder)
+        {
+            _builder = builder;
+            _builder.EnsureCapacity(_builder._length + literalLength + formattedCount * 11);
+        }
+
+        public void AppendLiteral(string value) => _builder.Append(value);
+
+        public void AppendFormatted<T>(T value) => _builder.Append(value);
+
+        public void AppendFormatted<T>(T value, string? format) => _builder.Append(value, format);
+
+        public void AppendFormatted<T>(T value, int alignment)
+        {
+            var startingPos = _builder._length;
+            _builder.Append(value);
+            if (alignment != 0)
+            {
+                AppendOrInsertAlignmentIfNeeded(startingPos, alignment);
+            }
+        }
+
+        public void AppendFormatted<T>(T value, int alignment, string? format)
+        {
+            var startingPos = _builder._length;
+            _builder.Append(value, format);
+            if (alignment != 0)
+            {
+                AppendOrInsertAlignmentIfNeeded(startingPos, alignment);
+            }
+        }
+
+        public void AppendFormatted(scoped ReadOnlySpan<char> value) => _builder.Append(value);
+
+        public void AppendFormatted(scoped ReadOnlySpan<char> value, int alignment = 0, string? format = null)
+        {
+            var leftAlign = false;
+            if (alignment < 0)
+            {
+                leftAlign = true;
+                alignment = -alignment;
+            }
+
+            var paddingRequired = alignment - value.Length;
+            if (paddingRequired <= 0)
+            {
+                _builder.Append(value);
+                return;
+            }
+
+            _builder.EnsureCapacity(_builder._length + value.Length + paddingRequired);
+            if (leftAlign)
+            {
+                _builder.Append(value);
+                _builder.AppendSpan(paddingRequired).Fill(' ');
+            }
+            else
+            {
+                _builder.AppendSpan(paddingRequired).Fill(' ');
+                _builder.Append(value);
+            }
+        }
+
+        public void AppendFormatted(string? value) => _builder.Append(value);
+
+        public void AppendFormatted(string? value, int alignment = 0, string? format = null) =>
+            AppendFormatted<string?>(value, alignment, format);
+
+        public void AppendFormatted(object? value, int alignment = 0, string? format = null) =>
+            AppendFormatted<object?>(value, alignment, format);
+
+        private void AppendOrInsertAlignmentIfNeeded(int startingPos, int alignment)
+        {
+            var charsWritten = _builder._length - startingPos;
+
+            var leftAlign = false;
+            if (alignment < 0)
+            {
+                leftAlign = true;
+                alignment = -alignment;
+            }
+
+            var paddingNeeded = alignment - charsWritten;
+            if (paddingNeeded <= 0)
+            {
+                return;
+            }
+
+            if (leftAlign)
+            {
+                _builder.AppendSpan(paddingNeeded).Fill(' ');
+            }
+            else
+            {
+                // Shift content right, fill padding on left
+                _builder.AppendSpan(paddingNeeded);
+                _builder._chars.Slice(startingPos, charsWritten)
+                    .CopyTo(_builder._chars[(startingPos + paddingNeeded)..]);
+                _builder._chars.Slice(startingPos, paddingNeeded).Fill(' ');
+            }
+        }
+    }
 }

Projects/Server/Client/ClientVersion.cs

@@ -210,7 +210,7 @@ public class ClientVersion : IComparable<ClientVersion>, IComparer<ClientVersion
 
     private string ToStringImpl()
     {
-        using var builder = ValueStringBuilder.Create();
+        using var builder = new ValueStringBuilder(stackalloc char[32]);
 
         if (Type == ClientType.SA)
         {

Projects/Server/Localization/LocalizationEntry.cs

@@ -51,7 +51,7 @@ public class LocalizationEntry
 
     private static void ParseText(string text, out string[] textSlices, out string stringFormatter)
     {
-        var sb = ValueStringBuilder.Create(256);
+        using var sb = ValueStringBuilder.Create(256);
         using var queue = PooledRefQueue<string>.Create();
 
         var hasMatch = false;
@@ -81,8 +81,6 @@ public class LocalizationEntry
 
         textSlices = queue.ToArray();
         stringFormatter = hasMatch ? sb.ToString() : null;
-
-        sb.Dispose();
     }
 
     /// <summary>

Projects/Server/Maps/MapSelection.cs

@@ -42,7 +42,7 @@ public static class MapSelection
 
     public static string ToCommaDelimitedString(this MapSelectionFlags flags)
     {
-        using var builder = ValueStringBuilder.Create();
+        using var builder = new ValueStringBuilder(stackalloc char[160]);
 
         foreach (var flag in flags.GetEnumerable())
         {

Projects/Server/Text/ISelfInterpolatedStringHandler.cs

@@ -20,21 +20,21 @@ namespace Server.Text;
 
 public interface ISelfInterpolatedStringHandler
 {
-    public void Add([InterpolatedStringHandlerArgument("")] ref InterpolatedStringHandler handler);
+    void Add([InterpolatedStringHandlerArgument("")] ref InterpolatedStringHandler handler);
-    public void InitializeInterpolation(int literalLength, int formattedCount);
+    void InitializeInterpolation(int literalLength, int formattedCount);
-    public void AppendLiteral(string value);
+    void AppendLiteral(string value);
-    public void AppendFormatted<T>(T value);
+    void AppendFormatted<T>(T value);
-    public void AppendFormatted<T>(T value, string? format);
+    void AppendFormatted<T>(T value, string? format);
-    public void AppendFormatted<T>(T value, int alignment);
+    void AppendFormatted<T>(T value, int alignment);
-    public void AppendFormatted<T>(T value, int alignment, string? format);
+    void AppendFormatted<T>(T value, int alignment, string? format);
-    public void AppendFormatted(ReadOnlySpan<char> value);
+    void AppendFormatted(ReadOnlySpan<char> value);
-    public void AppendFormatted(ReadOnlySpan<char> value, int alignment, string? format = null);
+    void AppendFormatted(ReadOnlySpan<char> value, int alignment, string? format = null);
-    public void AppendFormatted(object? value, int alignment = 0, string? format = null);
+    void AppendFormatted(object? value, int alignment = 0, string? format = null);
-    public void AppendFormatted(string? value);
+    void AppendFormatted(string? value);
-    public void AppendFormatted(string? value, int alignment, string? format = null);
+    void AppendFormatted(string? value, int alignment, string? format = null);
 
     [InterpolatedStringHandler]
-    public ref struct InterpolatedStringHandler
+    ref struct InterpolatedStringHandler
     {
         private ISelfInterpolatedStringHandler _parent;
 

Projects/UOContent/Commands/Handlers.cs

@@ -1,6 +1,6 @@
 using System.Collections.Generic;
-using System.Text;
 using Server.Commands.Generic;
+using Server.Text;
 using Server.Engines.Help;
 using Server.Gumps;
 using Server.Items;
@@ -88,7 +88,7 @@ namespace Server.Commands
 
                 if (!reg.IsDefault)
                 {
-                    var builder = new StringBuilder();
+                    using var builder = ValueStringBuilder.Create(256);
 
                     builder.Append(reg);
                     reg = reg.Parent;
@@ -99,7 +99,7 @@ namespace Server.Commands
                         reg = reg.Parent;
                     }
 
-                    from.SendMessage($"Your region is {builder}.");
+                    from.SendMessage($"Your region is {builder.ToString()}.");
                 }
             }
         }
@@ -594,7 +594,7 @@ namespace Server.Commands
 
             list.Sort();
 
-            var sb = new StringBuilder();
+            using var sb = ValueStringBuilder.Create(256);
 
             if (list.Count > 0)
             {
@@ -608,7 +608,7 @@ namespace Server.Commands
                 if (sb.Length + 1 + v.Length >= 256)
                 {
                     m.SendAsciiMessage(0x482, sb.ToString());
-                    sb = new StringBuilder();
+                    sb.Reset();
                     sb.Append(v);
                 }
                 else

Projects/UOContent/Commands/Logging.cs

@@ -1,6 +1,6 @@
 using System.IO;
-using System.Text;
 using Server.Accounting;
+using Server.Text;
 
 namespace Server.Commands
 {
@@ -110,11 +110,12 @@ namespace Server.Commands
                 return ip;
             }
 
-            var sb = new StringBuilder(ip);
+            using var sb = ValueStringBuilder.Create(ip.Length);
+            sb.Append(ip);
 
             for (var i = 0; i < m_NotSafe.Length; ++i)
             {
-                sb.Replace(m_NotSafe[i], '_');
+                sb.Replace(m_NotSafe[i], '_', 0, sb.Length);
             }
 
             return sb.ToString();

Projects/UOContent/Commands/Object Creation/Add.cs

@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection;
-using System.Text;
 using Server.Gumps;
 using Server.Items;
 using Server.Text;
@@ -355,7 +354,7 @@ public static class Add
 
             var sendError = true;
 
-            var sb = new StringBuilder();
+            using var sb = ValueStringBuilder.Create();
             sb.Append("Serials: ");
 
             if (packs != null)

Projects/UOContent/Compression/TarArchive.cs

@@ -96,7 +96,7 @@ namespace Server.Compression
 
             new FileInfo(destinationArchiveFileName).EnsureDirectory();
 
-            var sb = ValueStringBuilder.Create();
+            using var sb = ValueStringBuilder.Create();
             var i = 0;
             foreach (var path in paths)
             {
@@ -111,7 +111,6 @@ namespace Server.Compression
                 }
             }
             var pathsToCompress = sb.ToString();
-            sb.Dispose();
 
             var tarFlags = compressCommand == null ? "-acf" : "-cf";
             var useExternalCompression = compressCommand != null ? $"--use-compress-program \"{compressCommand}\" " : "";

Projects/UOContent/Engines/ConPVP/Games/BombingRun.cs

@@ -1,12 +1,12 @@
 using System;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
-using System.Text;
 using ModernUO.Serialization;
 using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;
 using Server.Targeting;
+using Server.Text;
 
 namespace Server.Engines.ConPVP;
 
@@ -1692,7 +1692,7 @@ public sealed class BRGame : EventGame
 
         var tourney = m_Context.m_Tournament;
 
-        var sb = new StringBuilder();
+        using var sb = ValueStringBuilder.Create(256);
 
         if (tourney != null)
         {
@@ -1731,7 +1731,8 @@ public sealed class BRGame : EventGame
 
         if (Controller != null)
         {
-            sb.Append(' ').Append(Controller.Title);
+            sb.Append(' ');
+            sb.Append(Controller.Title);
         }
 
         var title = sb.ToString();
@@ -1758,7 +1759,7 @@ public sealed class BRGame : EventGame
                     continue;
                 }
 
-                sb = new StringBuilder();
+                sb.Reset();
 
                 sb.Append(title);
 

Projects/UOContent/Engines/ConPVP/Games/CTF.cs

@@ -1,12 +1,12 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using ModernUO.Serialization;
 using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;
 using Server.Network;
 using Server.Targeting;
+using Server.Text;
 
 namespace Server.Engines.ConPVP;
 
@@ -1072,7 +1072,7 @@ public sealed class CTFGame : EventGame
 
         var tourney = m_Context.m_Tournament;
 
-        var sb = new StringBuilder();
+        using var sb = ValueStringBuilder.Create(256);
 
         if (tourney != null)
         {
@@ -1111,7 +1111,8 @@ public sealed class CTFGame : EventGame
 
         if (Controller != null)
         {
-            sb.Append(' ').Append(Controller.Title);
+            sb.Append(' ');
+            sb.Append(Controller.Title);
         }
 
         var title = sb.ToString();
@@ -1144,7 +1145,7 @@ public sealed class CTFGame : EventGame
 
                 // "Red v Blue CTF Champion"
 
-                sb = new StringBuilder();
+                sb.Reset();
 
                 sb.Append(title);
 

Projects/UOContent/Engines/ConPVP/Games/DoubleDom.cs

@@ -1,10 +1,10 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using ModernUO.Serialization;
 using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;
+using Server.Text;
 
 namespace Server.Engines.ConPVP;
 
@@ -648,7 +648,7 @@ public sealed class DDGame : EventGame
 
         var tourney = m_Context.m_Tournament;
 
-        var sb = new StringBuilder();
+        using var sb = ValueStringBuilder.Create(256);
 
         if (tourney != null)
         {
@@ -687,7 +687,8 @@ public sealed class DDGame : EventGame
 
         if (Controller != null)
         {
-            sb.Append(' ').Append(Controller.Title);
+            sb.Append(' ');
+            sb.Append(Controller.Title);
         }
 
         var title = sb.ToString();
@@ -720,7 +721,7 @@ public sealed class DDGame : EventGame
 
                 // "Red v Blue DD Champion"
 
-                sb = new StringBuilder();
+                sb.Reset();
 
                 sb.Append(title);
 

Projects/UOContent/Engines/ConPVP/Games/KingOfTheHill.cs

@@ -1,10 +1,10 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using ModernUO.Serialization;
 using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;
+using Server.Text;
 
 namespace Server.Engines.ConPVP;
 
@@ -993,7 +993,7 @@ public sealed class KHGame : EventGame
 
         var tourney = m_Context.m_Tournament;
 
-        var sb = new StringBuilder();
+        using var sb = ValueStringBuilder.Create(256);
 
         if (tourney != null)
         {
@@ -1027,7 +1027,8 @@ public sealed class KHGame : EventGame
 
         if (Controller != null)
         {
-            sb.Append(' ').Append(Controller.Title);
+            sb.Append(' ');
+            sb.Append(Controller.Title);
         }
 
         var title = sb.ToString();
@@ -1058,7 +1059,7 @@ public sealed class KHGame : EventGame
                     continue;
                 }
 
-                sb = new StringBuilder();
+                sb.Reset();
 
                 sb.Append(title);
 

Projects/UOContent/Engines/ConPVP/Games/TourneyMatch.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using Server.Network;
+using Server.Text;
 
 namespace Server.Engines.ConPVP
 {
@@ -11,21 +11,18 @@ namespace Server.Engines.ConPVP
         {
             Participants = participants;
 
+            using var sb = new ValueStringBuilder(stackalloc char[256]);
+
             for (var i = 0; i < participants.Count; ++i)
             {
                 var part = participants[i];
 
-                var sb = new StringBuilder();
+                sb.Reset();
-
                 sb.Append("Matched in a duel against ");
 
                 if (participants.Count > 2)
                 {
-                    sb.AppendFormat(
+                    sb.Append($"{participants.Count - 1} other {(part.Players.Count == 1 ? "players" : "teams")}: ");
-                        "{0} other {1}: ",
-                        participants.Count - 1,
-                        part.Players.Count == 1 ? "players" : "teams"
-                    );
                 }
 
                 var hasAppended = false;

Projects/UOContent/Engines/ConPVP/Gumps/AcceptTeamGump.cs

@@ -82,7 +82,7 @@ namespace Server.Engines.ConPVP
 
             AddImage(215, -43, 0xEE40);
 
-            using var sb = ValueStringBuilder.Create(128);
+            using var sb = new ValueStringBuilder(stackalloc char[64]);
 
             if (tourney.TourneyType == TourneyType.FreeForAll)
             {
@@ -90,13 +90,11 @@ namespace Server.Engines.ConPVP
             }
             else if (tourney.TourneyType == TourneyType.RandomTeam)
             {
-                sb.Append(tourney.ParticipantsPerMatch);
+                sb.Append($"{tourney.ParticipantsPerMatch}-Team");
-                sb.Append("-Team");
             }
             else if (tourney.TourneyType == TourneyType.Faction)
             {
-                sb.Append(tourney.ParticipantsPerMatch);
+                sb.Append($"{tourney.ParticipantsPerMatch}-Team Faction");
-                sb.Append("-Team Faction");
             }
             else if (tourney.TourneyType == TourneyType.RedVsBlue)
             {
@@ -117,8 +115,7 @@ namespace Server.Engines.ConPVP
 
             if (tourney.EventController != null)
             {
-                sb.Append(' ');
+                sb.Append($" {tourney.EventController.Title}");
-                sb.Append(tourney.EventController.Title);
             }
 
             sb.Append(" Tournament Invitation");

Projects/UOContent/Engines/ConPVP/Gumps/ArenaGump.cs

@@ -1,9 +1,9 @@
 using System.Collections.Generic;
-using System.Text;
 using ModernUO.Serialization;
 using Server.Gumps;
 using Server.Mobiles;
 using Server.Network;
+using Server.Text;
 
 namespace Server.Engines.ConPVP;
 
@@ -97,6 +97,8 @@ public class ArenaGump : Gump
         AddButton(499 + 40 - 12 - 63 - 4 - 63, height - 12 - 24, 247, 248, 1);
         AddButton(499 + 40 - 12 - 63, height - 12 - 24, 241, 242, 2);
 
+        var sb = new ValueStringBuilder(stackalloc char[256]);
+
         for (var i = 0; i < list.Count; ++i)
         {
             var ar = list[i];
@@ -112,7 +114,7 @@ public class ArenaGump : Gump
             AddBorderedText(x + 5, y + 5, 115 - 5, ar.Name ?? "(no name)", color, 0);
             x += 115;
 
-            var sb = new StringBuilder();
+            sb.Reset();
 
             if (ar.Players.Count > 0)
             {
@@ -154,10 +156,10 @@ public class ArenaGump : Gump
                     }
                 }
 
-                Append(sb, p1);
+                Append(ref sb, p1);
-                Append(sb, p2);
+                Append(ref sb, p2);
-                Append(sb, p3);
+                Append(ref sb, p3);
-                Append(sb, p4);
+                Append(ref sb, p4);
 
                 if (ar.Players.Count > 4)
                 {
@@ -174,9 +176,11 @@ public class ArenaGump : Gump
 
             AddBorderedText(x, y + 5, 40, Html.Center($"{ar.Spectators}"), color, 0);
         }
+
+        sb.Dispose();
     }
 
-    private void Append(StringBuilder sb, LadderEntry le)
+    private void Append(ref ValueStringBuilder sb, LadderEntry le)
     {
         if (le == null)
         {

Projects/UOContent/Engines/ConPVP/Gumps/ConfirmSignupGump.cs

@@ -92,7 +92,7 @@ namespace Server.Engines.ConPVP
             AddImage(215, -43, 0xEE40);
             // AddImage( 330, 141, 0x8BA );
 
-            using var sb = ValueStringBuilder.Create(128);
+            using var sb = new ValueStringBuilder(stackalloc char[64]);
 
             if (tourney.TourneyType == TourneyType.FreeForAll)
             {
@@ -100,13 +100,11 @@ namespace Server.Engines.ConPVP
             }
             else if (tourney.TourneyType == TourneyType.RandomTeam)
             {
-                sb.Append(tourney.ParticipantsPerMatch);
+                sb.Append($"{tourney.ParticipantsPerMatch}-Team");
-                sb.Append("-Team");
             }
             else if (tourney.TourneyType == TourneyType.Faction)
             {
-                sb.Append(tourney.ParticipantsPerMatch);
+                sb.Append($"{tourney.ParticipantsPerMatch}-Team Faction");
-                sb.Append("-Team Faction");
             }
             else if (tourney.TourneyType == TourneyType.RedVsBlue)
             {
@@ -127,8 +125,7 @@ namespace Server.Engines.ConPVP
 
             if (tourney.EventController != null)
             {
-                sb.Append(' ');
+                sb.Append($" {tourney.EventController.Title}");
-                sb.Append(tourney.EventController.Title);
             }
 
             sb.Append(" Tournament Signup");

Projects/UOContent/Engines/ConPVP/Gumps/TournamentBracketGump.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-using System.Text;
 using Server.Gumps;
 using Server.Mobiles;
 using Server.Network;
@@ -60,8 +59,7 @@ namespace Server.Engines.ConPVP
                         }
                         else if (tourney.TourneyType == TourneyType.RandomTeam)
                         {
-                            sb.Append(tourney.ParticipantsPerMatch);
+                            sb.Append($"{tourney.ParticipantsPerMatch}-Team");
-                            sb.Append("-Team");
                         }
                         else if (tourney.TourneyType == TourneyType.RedVsBlue)
                         {
@@ -69,8 +67,7 @@ namespace Server.Engines.ConPVP
                         }
                         else if (tourney.TourneyType == TourneyType.Faction)
                         {
-                            sb.Append(tourney.ParticipantsPerMatch);
+                            sb.Append($"{tourney.ParticipantsPerMatch}-Team Faction");
-                            sb.Append("-Team Faction");
                         }
                         else
                         {
@@ -87,8 +84,7 @@ namespace Server.Engines.ConPVP
 
                         if (tourney.EventController != null)
                         {
-                            sb.Append(' ');
+                            sb.Append($" {tourney.EventController.Title}");
-                            sb.Append(tourney.EventController.Title);
                         }
 
                         sb.Append(" Tournament Bracket");
@@ -461,7 +457,7 @@ namespace Server.Engines.ConPVP
                                 color = 0x666666;
                             }
 
-                            var sb = new StringBuilder();
+                            using var sb = ValueStringBuilder.Create(512);
 
                             if (m_Tournament.TourneyType == TourneyType.Standard)
                             {

Projects/UOContent/Engines/ConPVP/Participant.cs

@@ -1,6 +1,6 @@
 using System;
-using System.Text;
 using Server.Mobiles;
+using Server.Text;
 
 namespace Server.Engines.ConPVP
 {
@@ -74,7 +74,7 @@ namespace Server.Engines.ConPVP
         {
             get
             {
-                var sb = new StringBuilder();
+                using var sb = ValueStringBuilder.Create(256);
 
                 for (var i = 0; i < Players.Length; ++i)
                 {

Projects/UOContent/Engines/ConPVP/Tournament.cs

@@ -1,9 +1,9 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using Server.Factions;
 using Server.Items;
 using Server.Regions;
+using Server.Text;
 
 namespace Server.Engines.ConPVP
 {
@@ -237,7 +237,7 @@ namespace Server.Engines.ConPVP
                 return;
             }
 
-            var sb = new StringBuilder();
+            using var sb = ValueStringBuilder.Create(512);
 
             sb.Append("The match has ended in a tie ");
 
@@ -284,7 +284,7 @@ namespace Server.Engines.ConPVP
             {
                 case TieType.FullAdvancement:
                     {
-                        sb.AppendFormat("In accordance with the rules, {0} parties are advanced.", whole);
+                        sb.Append($"In accordance with the rules, {whole} parties are advanced.");
                         break;
                     }
                 case TieType.FullElimination:
@@ -294,7 +294,7 @@ namespace Server.Engines.ConPVP
                             Undefeated.Remove(remaining[j]);
                         }
 
-                        sb.AppendFormat("In accordance with the rules, {0} parties are eliminated.", whole);
+                        sb.Append($"In accordance with the rules, {whole} parties are eliminated.");
                         break;
                     }
                 case TieType.Random:
@@ -311,11 +311,7 @@ namespace Server.Engines.ConPVP
 
                         if (advanced != null)
                         {
-                            sb.AppendFormat(
+                            sb.Append($"In accordance with the rules, {advanced.NameList} {(advanced.Players.Count == 1 ? "is" : "are")} advanced.");
-                                "In accordance with the rules, {0} {1} advanced.",
-                                advanced.NameList,
-                                advanced.Players.Count == 1 ? "is" : "are"
-                            );
                         }
 
                         break;
@@ -344,11 +340,7 @@ namespace Server.Engines.ConPVP
 
                         if (advanced != null)
                         {
-                            sb.AppendFormat(
+                            sb.Append($"In accordance with the rules, {advanced.NameList} {(advanced.Players.Count == 1 ? "is" : "are")} advanced.");
-                                "In accordance with the rules, {0} {1} advanced.",
-                                advanced.NameList,
-                                advanced.Players.Count == 1 ? "is" : "are"
-                            );
                         }
 
                         break;
@@ -377,11 +369,7 @@ namespace Server.Engines.ConPVP
 
                         if (advanced != null)
                         {
-                            sb.AppendFormat(
+                            sb.Append($"In accordance with the rules, {advanced.NameList} {(advanced.Players.Count == 1 ? "is" : "are")} advanced.");
-                                "In accordance with the rules, {0} {1} advanced.",
-                                advanced.NameList,
-                                advanced.Players.Count == 1 ? "is" : "are"
-                            );
                         }
 
                         break;
@@ -432,7 +420,7 @@ namespace Server.Engines.ConPVP
 
         public void HandleWon(Arena arena, TourneyMatch match, TourneyParticipant winner)
         {
-            var sb = new StringBuilder();
+            using var sb = ValueStringBuilder.Create(512);
 
             sb.Append("The match is complete. ");
             sb.Append(winner.NameList);
@@ -448,11 +436,7 @@ namespace Server.Engines.ConPVP
 
             if (match.Participants.Count > 2)
             {
-                sb.AppendFormat(
+                sb.Append($"{match.Participants.Count - 1} other {(winner.Players.Count == 1 ? "players" : "teams")}: ");
-                    "{0} other {1}: ",
-                    match.Participants.Count - 1,
-                    winner.Players.Count == 1 ? "players" : "teams"
-                );
             }
 
             var hasAppended = false;
@@ -592,7 +576,7 @@ namespace Server.Engines.ConPVP
             cash /= 1000;
             cash *= 1000;
 
-            var sb = new StringBuilder();
+            using var sb = ValueStringBuilder.Create(256);
 
             if (TourneyType == TourneyType.FreeForAll)
             {
@@ -628,7 +612,8 @@ namespace Server.Engines.ConPVP
 
             if (EventController != null)
             {
-                sb.Append(' ').Append(EventController.Title);
+                sb.Append(' ');
+                sb.Append(EventController.Title);
             }
 
             sb.Append(" Champion");

Projects/UOContent/Engines/ConPVP/TourneyParticipant.cs

@@ -1,6 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
+using Server.Text;
 
 namespace Server.Engines.ConPVP
 {
@@ -56,7 +56,7 @@ namespace Server.Engines.ConPVP
         {
             get
             {
-                var sb = new StringBuilder();
+                using var sb = ValueStringBuilder.Create(256);
 
                 for (var i = 0; i < Players.Count; ++i)
                 {

Projects/UOContent/Engines/Ethics/Evil/Powers/UnholySense.cs

@@ -45,7 +45,7 @@ public sealed class UnholySense : Power
             ++enemyCount;
         }
 
-        using var sb = ValueStringBuilder.Create();
+        using var sb = new ValueStringBuilder(stackalloc char[96]);
         sb.Append($"You sense {(enemyCount == 0 ? "no" : enemyCount.ToString())} {(enemyCount == 1 ? "enemy" : "enemies")}");
 
         if (primary != null)

Projects/UOContent/Engines/Ethics/Hero/Powers/HolySense.cs

@@ -45,7 +45,7 @@ public sealed class HolySense : Power
             ++enemyCount;
         }
 
-        using var sb = ValueStringBuilder.Create();
+        using var sb = new ValueStringBuilder(stackalloc char[96]);
         sb.Append($"You sense {(enemyCount == 0 ? "no" : enemyCount.ToString())} {(enemyCount == 1 ? "enemy" : "enemies")}");
 
         if (primary != null)

Projects/UOContent/Engines/Help/SpeechLogGump.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using Server.Accounting;
+using Server.Text;
 using Server.Gumps;
 using Server.Network;
 
@@ -62,7 +62,7 @@ namespace Server.Engines.Help
                 var max = log.Count - (lastPage - page) * MaxEntriesPerPage;
                 var min = Math.Max(max - MaxEntriesPerPage, 0);
 
-                var builder = new StringBuilder();
+                using var builder = ValueStringBuilder.Create();
 
                 for (var i = min; i < max; i++)
                 {

Projects/UOContent/Engines/Player Murder System/BountyMessage.cs

@@ -163,43 +163,27 @@ public static class BountyMessage
         {
             case 0:
                 {
-                    lineBuilder.Append("Bounty for");
+                    lineBuilder.Append($"Bounty for {player.RawName}!"); break;
-                    lineBuilder.Append(player.RawName);
-                    lineBuilder.Append("!");
-                    break;
                 }
             case 1:
                 {
-                    lineBuilder.Append(player.RawName);
+                    lineBuilder.Append($"{player.RawName} must die!"); break;
-                    lineBuilder.Append(" must die!");
-                    break;
                 }
             case 2:
                 {
-                    lineBuilder.Append("A price on ");
+                    lineBuilder.Append($"A price on {player.RawName}!"); break;
-                    lineBuilder.Append(player.RawName);
-                    lineBuilder.Append('!');
-                    break;
                 }
             case 3:
                 {
-                    lineBuilder.Append(player.RawName);
+                    lineBuilder.Append($"{player.RawName} outlawed!"); break;
-                    lineBuilder.Append(" outlawed!");
-                    break;
                 }
             case 4:
                 {
-                    lineBuilder.Append("Execute ");
+                    lineBuilder.Append($"Execute {player.RawName}!"); break;
-                    lineBuilder.Append(player.RawName);
-                    lineBuilder.Append('!');
-                    break;
                 }
             default:
                 {
-                    lineBuilder.Append("WANTED: ");
+                    lineBuilder.Append($"WANTED: {player.RawName}!"); break;
-                    lineBuilder.Append(player.RawName);
-                    lineBuilder.Append('!');
-                    break;
                 }
         }
 
@@ -248,21 +232,7 @@ public static class BountyMessage
             _ => "  Lord British's bounty "
         };
 
-        paraBuilder.Append("The foul scum known as ");
+        paraBuilder.Append($"The foul scum known as {player.RawName} {verb}  For {pronoun} is responsible for {player.Kills} murders.  {intro} of {bounty} gold pieces for {possessive} head!");
-        paraBuilder.Append(player.RawName);
-        paraBuilder.Append(' ');
-        paraBuilder.Append(verb);
-        paraBuilder.Append("  For ");
-        paraBuilder.Append(pronoun);
-        paraBuilder.Append(" is responsible for ");
-        paraBuilder.Append(player.Kills);
-        paraBuilder.Append(" murders.  ");
-        paraBuilder.Append(intro);
-        paraBuilder.Append(" of ");
-        paraBuilder.Append(bounty);
-        paraBuilder.Append(" gold pieces for ");
-        paraBuilder.Append(possessive);
-        paraBuilder.Append(" head!");
 
         // Word-wrap at 28 chars and write each line directly (matching uo98 bountyboard.m CONST:28)
         WriteWordWrappedLines(ref writer, paraBuilder.AsSpan(), 28, textBuffer, ref lineCount);
@@ -276,22 +246,17 @@ public static class BountyMessage
         lineCount++;
 
         lineBuilder.Reset();
-        lineBuilder.Append("    - ");
+        lineBuilder.Append($"    - {GetHairStyle(player.HairItemID)}");
-        lineBuilder.Append(GetHairStyle(player.HairItemID));
         writer.WriteString(lineBuilder.AsSpan(), textBuffer, true);
         lineCount++;
 
         lineBuilder.Reset();
-        lineBuilder.Append("    - ");
+        lineBuilder.Append($"    - {GetHairColor(player.HairHue)} hair");
-        lineBuilder.Append(GetHairColor(player.HairHue));
-        lineBuilder.Append(" hair");
         writer.WriteString(lineBuilder.AsSpan(), textBuffer, true);
         lineCount++;
 
         lineBuilder.Reset();
-        lineBuilder.Append("    - ");
+        lineBuilder.Append($"    - {GetSkinTone(player.Hue)} skin");
-        lineBuilder.Append(GetSkinTone(player.Hue));
-        lineBuilder.Append(" skin");
         writer.WriteString(lineBuilder.AsSpan(), textBuffer, true);
         lineCount++;
 
@@ -300,9 +265,7 @@ public static class BountyMessage
         lineCount++;
 
         lineBuilder.Reset();
-        lineBuilder.Append("If you kill ");
+        lineBuilder.Append($"If you kill {objective}, remove the");
-        lineBuilder.Append(objective);
-        lineBuilder.Append(", remove the");
         writer.WriteString(lineBuilder.AsSpan(), textBuffer, true);
         lineCount++;
 

Projects/UOContent/Gumps/AdminGump.cs

@@ -1119,12 +1119,7 @@ namespace Server.Gumps
                             }
 
                             var c = a.Comments[i];
-                            sb.Append('[');
+                            sb.Append($"[{c.AddedBy} on {c.LastModified}]<BR>{c.Content}");
-                            sb.Append(c.AddedBy);
-                            sb.Append(" on ");
-                            sb.Append(c.LastModified.ToString());
-                            sb.Append("]<BR>");
-                            sb.Append(c.Content);
                         }
 
                         AddHtml(20, 180, 380, 190, sb.ToString(), true, true);
@@ -1159,9 +1154,7 @@ namespace Server.Gumps
 
                             var tag = a.Tags[i];
 
-                            sb.Append(tag.Name);
+                            sb.Append($"{tag.Name} = {tag.Value}");
-                            sb.Append(" = ");
-                            sb.Append(tag.Value);
                         }
 
                         AddHtml(20, 180, 380, 190, sb.ToString(), true, true);

Projects/UOContent/Items/Armor/BaseArmor.cs

@@ -1561,7 +1561,7 @@ namespace Server.Items
 
             if (isMagicItem)
             {
-                var builder = ValueStringBuilder.Create(128);
+                var builder = new ValueStringBuilder(stackalloc char[128]);
 
                 var durabilityText = DurabilityText(out var articleAnDurability);
                 if (durabilityText != null)

Projects/UOContent/Items/Special/House Raffle/HouseRaffleStone.cs

@@ -305,7 +305,7 @@ public partial class HouseRaffleStone : Item
 
     public static string FormatLocation(Point3D loc, Map map, bool displayMap)
     {
-        using var result = ValueStringBuilder.Create();
+        using var result = new ValueStringBuilder(stackalloc char[48]);
 
         var xLong = 0;
         var yLat = 0;

Projects/UOContent/Items/Weapons/BaseWeapon.cs

@@ -3451,7 +3451,7 @@ public abstract partial class BaseWeapon
 
         if (isMagicItem)
         {
-            var builder = ValueStringBuilder.Create(128);
+            var builder = new ValueStringBuilder(stackalloc char[160]);
 
             var durabilityText = DurabilityText(out var articleAnDurability);
             if (durabilityText != null)

Projects/UOContent/Misc/ClientVerification.cs

@@ -94,7 +94,7 @@ namespace Server.Misc
                 return "There are no clients supported at this time.";
             }
 
-            using var builder = ValueStringBuilder.Create();
+            using var builder = new ValueStringBuilder(stackalloc char[192]);
             builder.Append("Please connect with a ");
             uint flags = 0;
             var i = 0;
@@ -115,7 +115,7 @@ namespace Server.Misc
 
         public static void ClientVersionReceived(NetState state, ClientVersion version)
         {
-            var sb = ValueStringBuilder.Create();
+            using var sb = ValueStringBuilder.Create();
 
             if (!_enable || state.Mobile?.AccessLevel != AccessLevel.Player)
             {
@@ -202,8 +202,6 @@ namespace Server.Misc
                         }
                 }
             }
-
-            sb.Dispose();
         }
 
         private static void OnKick(NetState ns)

Projects/UOContent/Mobiles/Townfolk/TownCrier.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using ModernUO.Serialization;
+using Server.Text;
 using Server.Gumps;
 using Server.Items;
 using Server.Network;
@@ -231,7 +231,7 @@ public class TownCrierGump : Gump
 
                 var toExpire = Utility.Max(tce.ExpireTime - Core.Now, TimeSpan.Zero);
 
-                var sb = new StringBuilder();
+                using var sb = ValueStringBuilder.Create(512);
 
                 sb.Append("[Expires: ");
 

Projects/UOContent/Skills/ForensicEval.cs

@@ -71,7 +71,7 @@ namespace Server.SkillHandlers
 
                         if (c.Looters.Count > 0)
                         {
-                            var sb = ValueStringBuilder.Create(128);
+                            using var sb = new ValueStringBuilder(stackalloc char[128]);
                             var i = 0;
                             foreach (var looter in c.Looters)
                             {
@@ -93,7 +93,6 @@ namespace Server.SkillHandlers
 
                             // This body has been disturbed by ~1_PLAYER_NAMES~
                             from.SendLocalizedMessage(1042752, sb.ToString());
-                            sb.Dispose();
                         }
                         else
                         {

Projects/UOContent/Special Systems/Engines/TestCenter.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Text;
 using CommunityToolkit.HighPerformance;
 using Server.Commands;
 using Server.Factions;
@@ -7,6 +6,7 @@ using Server.Gumps;
 using Server.Items;
 using Server.Mobiles;
 using Server.Network;
+using Server.Text;
 
 namespace Server.Misc
 {
@@ -703,7 +703,7 @@ namespace Server.Misc
 
                             Array.Sort(strings);
 
-                            var sb = new StringBuilder();
+                            using var sb = ValueStringBuilder.Create(256);
 
                             if (strings.Length > 0)
                             {
@@ -728,7 +728,7 @@ namespace Server.Misc
                                         sb.ToString()
                                     );
 
-                                    sb = new StringBuilder();
+                                    sb.Reset();
                                     sb.Append(v);
                                 }
                                 else

dev-docs/claude-skills/modernuo-string-handling.md

@@ -0,0 +1,133 @@
+# ModernUO String Handling Skill
+
+## When This Skill Applies
+- Any code that builds strings dynamically (concatenation, formatting, interpolation)
+- Converting `System.Text.StringBuilder` to `ValueStringBuilder`
+- Packet string construction
+- Gump/message text building
+
+## Core Rule
+**Never use `System.Text.StringBuilder`**. Use `Server.Text.ValueStringBuilder` everywhere.
+
+## Quick Reference
+
+### Construction
+```csharp
+// Bounded output (preferred): zero heap allocation
+using var sb = new ValueStringBuilder(stackalloc char[128]);
+
+// Unbounded output: rents from STArrayPool
+using var sb = ValueStringBuilder.Create(256);
+using var sb = ValueStringBuilder.Create(); // default 64 chars
+```
+
+### String Interpolation
+Works with stackalloc — writes directly into the builder's buffer:
+```csharp
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.Append($"Player {name} has {kills} kills");
+```
+
+### Reuse via Reset
+Use `Reset()` instead of creating a new builder:
+```csharp
+using var sb = new ValueStringBuilder(stackalloc char[128]);
+foreach (var item in items)
+{
+    sb.Reset();
+    sb.Append($"{item.Name}: {item.Value}");
+    Process(sb.ToString());
+}
+```
+
+### Reading Results
+- `sb.ToString()` — when you need a string (allocates)
+- `sb.AsSpan()` — when consumer accepts `ReadOnlySpan<char>` (zero-alloc)
+
+## Common Mistakes
+
+### 1. Using StringBuilder
+```csharp
+// BAD
+var sb = new StringBuilder();
+sb.Append(name);
+return sb.ToString();
+
+// GOOD
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.Append(name);
+return sb.ToString();
+```
+
+### 2. Forgetting `using var`
+```csharp
+// BAD: pooled array may leak if Grow() happened
+var sb = ValueStringBuilder.Create();
+return sb.ToString(); // never disposed!
+
+// GOOD
+using var sb = ValueStringBuilder.Create();
+return sb.ToString();
+```
+
+### 3. Chaining Append calls
+```csharp
+// BAD: VSB Append returns void, not this
+sb.Append("a").Append("b");
+
+// GOOD
+sb.Append("a");
+sb.Append("b");
+
+// BETTER: use interpolation
+sb.Append($"a{value}b");
+```
+
+### 4. Reassigning a using variable
+```csharp
+// BAD: can't reassign using var
+using var sb = ValueStringBuilder.Create();
+sb = ValueStringBuilder.Create(); // CS1656!
+
+// GOOD: use Reset()
+using var sb = ValueStringBuilder.Create();
+sb.Reset();
+```
+
+### 5. `using var` with `ref` extension methods
+```csharp
+// BAD: CS1657 — using var can't be passed by ref
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.AppendSpaceWithArticle(text, articleAn); // takes ref VSB
+
+// GOOD: manual Dispose
+var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.AppendSpaceWithArticle(text, articleAn);
+var result = sb.ToString();
+sb.Dispose();
+```
+
+### 6. No AppendFormat — use `$"..."` interpolation
+```csharp
+// BAD: AppendFormat doesn't exist on VSB (no object[] params equivalent)
+sb.AppendFormat("{0:N0} points, {1:N0} kills", score, kills);
+
+// GOOD: use interpolation with format specifiers (zero boxing, zero intermediate strings)
+sb.Append($"{score:N0} points, {kills:N0} kills");
+```
+
+## Capacity Sizing Guide
+
+| Content | Recommended |
+|---|---|
+| Version strings, coordinates | `stackalloc char[32-48]` |
+| Player names, short messages | `stackalloc char[64]` |
+| Item descriptions, titles | `stackalloc char[128]` |
+| Paragraph text, HTML snippets | `stackalloc char[256]` |
+| Large HTML, gump content | `Create(512)` or `Create()` |
+| Unbounded (logs, file paths) | `Create()` |
+
+## Related Docs
+- `dev-docs/string-handling.md` — full reference
+- `dev-docs/code-standards.md` — memory management rules
+- `dev-docs/property-lists.md` — IPropertyList string interpolation (different handler)

dev-docs/code-standards.md

@@ -486,7 +486,7 @@ finally
 - Use `PooledRefList<T>` instead of `new List<T>()`
 - Use `stackalloc` for small fixed-size buffers
 - Use `STArrayPool<T>` for larger buffers
-- Avoid string concatenation in loops (use `StringBuilder` or string interpolation in `IPropertyList`)
+- Use `ValueStringBuilder` with `stackalloc` for string building (never `System.Text.StringBuilder`) → `dev-docs/string-handling.md`
 
 ---
 

dev-docs/string-handling.md

@@ -0,0 +1,220 @@
+# String Handling in ModernUO
+
+This document covers the string building utilities in `Projects/Server/Text/` and `Projects/Server/Buffers/`, when to use each, and how to avoid common allocation pitfalls.
+
+## Table of Contents
+1. [ValueStringBuilder](#valuestringbuilder)
+2. [RawInterpolatedStringHandler](#rawinterpolatedstringhandler)
+3. [StringHelpers](#stringhelpers)
+4. [TextEncoding](#textencoding)
+5. [Decision Guide](#decision-guide)
+
+---
+
+## ValueStringBuilder
+
+**Location**: `Projects/Server/Buffers/ValueStringBuilder.cs`
+**Namespace**: `Server.Text`
+
+A `ref struct` string builder that avoids heap allocations entirely when backed by `stackalloc`. This is the **preferred** string builder for all ModernUO code — do not use `System.Text.StringBuilder`.
+
+### Construction Patterns
+
+**Stackalloc (preferred for bounded output)**:
+```csharp
+// Best: zero heap allocation, zero pool overhead
+using var sb = new ValueStringBuilder(stackalloc char[128]);
+sb.Append($"Hello {name}, score: {score}");
+return sb.ToString();
+```
+
+**Pooled (for unbounded or large output)**:
+```csharp
+// Rents from STArrayPool — returned on Dispose
+using var sb = ValueStringBuilder.Create(256);
+// or with default capacity (64):
+using var sb = ValueStringBuilder.Create();
+```
+
+### Choosing Capacity
+
+| Output size | Pattern |
+|---|---|
+| Known, <=256 chars | `new ValueStringBuilder(stackalloc char[N])` |
+| Known, >256 chars | `ValueStringBuilder.Create(N)` |
+| Unbounded/unknown | `ValueStringBuilder.Create()` (grows automatically) |
+
+If the stackalloc buffer is too small, the builder automatically grows to a pooled array. This is safe but costs a pool rent — size the stackalloc to fit the expected output.
+
+### String Interpolation (`$"..."`)
+
+`ValueStringBuilder` supports `$"..."` syntax via a copy-and-reconcile `InterpolationHandler`. This writes directly into the builder's buffer — **no intermediate allocation**, even with stackalloc.
+
+```csharp
+// Works with stackalloc — zero allocation
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.Append($"Player {name} has {kills} kills");
+sb.Append($" and {bounty} gold bounty");
+```
+
+**How it works**: The compiler passes a value copy of the builder to the handler. The copy shares the same underlying buffer (Span points to the same memory), so writes go to the original buffer. `Append()` reconciles by copying the handler's updated state back to the original. If the handler triggers a `Grow()`, the reconciliation updates the buffer reference.
+
+### Reusing a Builder
+
+Use `Reset()` to clear the builder for reuse instead of creating a new one:
+
+```csharp
+using var sb = new ValueStringBuilder(stackalloc char[128]);
+
+foreach (var item in items)
+{
+    sb.Reset(); // clear for next iteration
+    sb.Append($"{item.Name}: {item.Value}");
+    Process(sb.ToString());
+}
+```
+
+### Reading the Result
+
+| Method | Use when |
+|---|---|
+| `sb.ToString()` | You need a `string` (allocates) |
+| `sb.AsSpan()` | You can consume a `ReadOnlySpan<char>` (zero-alloc) |
+| `sb.AsSpan(terminate: true)` | You need a null-terminated span |
+
+### Disposal
+
+Always use `using var` for automatic disposal:
+```csharp
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+```
+
+If `using var` is not possible (e.g., the builder is passed by `ref` to extension methods, or `goto case` in switch blocks), use manual `Dispose()`:
+```csharp
+var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.AppendSpaceWithArticle(text, articleAn); // takes ref ValueStringBuilder
+var result = sb.ToString();
+sb.Dispose();
+```
+
+For stackalloc-only builders that never grow, `Dispose()` is a no-op. But always call it defensively — if a future change triggers growth, the pooled array needs returning.
+
+### Limitations
+
+- **No `AppendFormat`**: Use `$"..."` interpolation instead — it's more readable and zero-allocation:
+  ```csharp
+  // StringBuilder (old):
+  sb.AppendFormat("{0:N0} points, {1:N0} kills", score, kills);
+
+  // ValueStringBuilder:
+  sb.Append($"{score:N0} points, {kills:N0} kills");
+  ```
+  There is no `object[] params` equivalent for format strings. All formatting goes through `$"..."` interpolation which uses `ISpanFormattable.TryFormat` directly — zero boxing, zero intermediate strings.
+
+- **No chained Append**: `Append()` returns `void`, not `this`. Write `sb.Append(a); sb.Append(b);` instead of `sb.Append(a).Append(b)`.
+- **Ref struct constraints**: Cannot be stored in fields, captured by lambdas, or used in `async` methods. Scoped to the declaring method.
+- **`using var` + `ref` conflict**: A `using` variable cannot be passed by `ref`. If extension methods take `ref ValueStringBuilder`, use manual `Dispose()` instead.
+
+---
+
+## RawInterpolatedStringHandler
+
+**Location**: `Projects/Server/Buffers/RawInterpolatedStringHandler.cs`
+**Namespace**: `Server.Buffers`
+
+A `[InterpolatedStringHandler]` ref struct used internally by `ValueStringBuilder`'s interpolation support. You should not need to use this directly — use `sb.Append($"...")` instead.
+
+---
+
+## StringHelpers
+
+**Location**: `Projects/Server/Text/StringHelpers.cs`
+**Namespace**: `Server.Text`
+
+Extension methods for common string operations:
+
+| Method | Description |
+|---|---|
+| `Wrap(string, int perLine, int maxLines)` | Word-wrap text into lines |
+| `AppendSpaceWithArticle(ref ValueStringBuilder, string, bool)` | Append with "a"/"an" article prefix |
+| `Remove(ReadOnlySpan<char>, ...)` | Filter substrings from spans |
+| `Capitalize(string)` | Title-case with "the" handling |
+| `TrimMultiline(string)` | Trim each line in multiline text |
+
+---
+
+## TextEncoding
+
+**Location**: `Projects/Server/Text/TextEncoding.cs`
+**Namespace**: `Server.Text`
+
+UTF-8/Unicode encoding utilities used by the networking layer:
+
+| Method | Description |
+|---|---|
+| `GetBytesUtf8(string, Span<byte>)` | Encode string to UTF-8 in buffer |
+| `GetBytesUtf8(ReadOnlySpan<char>, Span<byte>)` | Encode char span to UTF-8 |
+| `GetStringUtf8(Span<byte>)` | Decode UTF-8 bytes to string (with filtering) |
+
+---
+
+## Decision Guide
+
+### When to use what
+
+```
+Need to build a string?
+├── In a hot path (packets, ticks, spatial queries)?
+│   └── ValueStringBuilder with stackalloc
+├── In game content (gumps, messages, commands)?
+│   └── ValueStringBuilder with stackalloc (bounded) or Create() (unbounded)
+├── Building an ObjectPropertyList tooltip?
+│   └── Use IPropertyList.Add($"...") — has its own handler
+├── In async/multi-threaded code (rare)?
+│   └── ValueStringBuilder.CreateMT() or System.Text.StringBuilder
+└── Never → System.Text.StringBuilder
+```
+
+### Do NOT use `System.Text.StringBuilder`
+
+`ValueStringBuilder` replaces `StringBuilder` in all game code. It avoids:
+- GC pressure from `StringBuilder`'s internal `char[]` allocations
+- The `StringBuilder` object allocation itself (24+ bytes on heap)
+- Thread-safe overhead in `ArrayPool<char>.Shared` (VSB uses lock-free `STArrayPool`)
+
+### Common patterns
+
+**Instead of string concatenation**:
+```csharp
+// BAD: allocates intermediate strings
+var msg = "Player " + name + " has " + kills + " kills";
+
+// GOOD: zero allocation with stackalloc
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.Append($"Player {name} has {kills} kills");
+var msg = sb.ToString(); // single allocation for the final string
+```
+
+**Instead of StringBuilder**:
+```csharp
+// BAD: StringBuilder allocates on heap
+var sb = new StringBuilder();
+sb.Append(name);
+sb.Append(": ");
+sb.Append(value);
+return sb.ToString();
+
+// GOOD: ValueStringBuilder with stackalloc
+using var sb = new ValueStringBuilder(stackalloc char[64]);
+sb.Append($"{name}: {value}");
+return sb.ToString();
+```
+
+**For packet string construction** (hot path):
+```csharp
+// Use AsSpan() to avoid ToString() allocation when the consumer accepts spans
+using var sb = new ValueStringBuilder(stackalloc char[32]);
+sb.Append(bounty);
+sb.Append(" gold");
+writer.WriteString(sb.AsSpan(), textBuffer); // zero-copy
+```