Document missing command error codes

USER_GUIDE.md

@@ -1872,6 +1872,9 @@ For scripts and AI agents that need to classify failures without substring-match
 | `E012_INTERRUPTED` | The user interrupted the command with Ctrl-C / signal cancellation |
 | `E013_INDEX_EXTRACTION_STALLED` | Index extraction made no forward progress within the bounded stall timeout |
 | `E014_REGEX_MATCH_TIMEOUT` | A user-supplied regular expression exceeded the bounded match timeout while executing |
+| `E015_FS_CASE_PROBE_FAILED` | Filesystem case-sensitivity probing failed before cdidx could select a safe path-casing policy |
+| `E016_CHECKPOINT_NOT_FOUND` | The requested database checkpoint name does not exist |
+| `E017_WORKSPACE_MANIFEST_INVALID` | A workspace manifest was found but failed JSON schema or safety validation |
 | `E018_QUERY_NOT_FOUND` | A lookup that requires a result did not match an indexed entity |
 | `E019_FILE_NOT_FOUND` | An exact indexed file path requested by a query command does not exist |
 | `E020_LINE_OUT_OF_RANGE` | A requested source line falls outside the indexed file's 1-based line range |
@@ -4920,6 +4923,9 @@ raw match density を正確に測る、といった理由で全 raw chunk hit 
 | `E012_INTERRUPTED` | Ctrl-C / signal cancellation でユーザーがコマンドを中断した |
 | `E013_INDEX_EXTRACTION_STALLED` | 制限付きの停止判定時間内に index 抽出が前進しなかった |
 | `E014_REGEX_MATCH_TIMEOUT` | ユーザー指定の正規表現が実行中に制限付き match timeout を超えた |
+| `E015_FS_CASE_PROBE_FAILED` | ファイルシステムの大文字小文字区別 probe に失敗し、安全な path casing policy を選択できなかった |
+| `E016_CHECKPOINT_NOT_FOUND` | 指定されたデータベース checkpoint 名が存在しない |
+| `E017_WORKSPACE_MANIFEST_INVALID` | workspace manifest JSON が見つかったが、schema または安全性の検証に失敗した |
 | `E018_QUERY_NOT_FOUND` | 結果必須の lookup が indexed entity に一致しなかった |
 | `E019_FILE_NOT_FOUND` | query command が要求した indexed file の完全一致 path が存在しない |
 | `E020_LINE_OUT_OF_RANGE` | 要求した source line が indexed file の 1-based 行範囲外だった |

changelog.d/unreleased/4644.docs.md

@@ -0,0 +1,16 @@
+---
+category: docs
+issues:
+  - 4644
+affected:
+  - USER_GUIDE.md
+  - tests/CodeIndex.Tests/DocumentationDriftTests.cs
+---
+
+## English
+
+- **Documented the complete stable command error-code taxonomy (#4644)** — the USER_GUIDE now includes E015–E017 in its English error-code table, with a contract test keeping both language tables synchronized with `CommandErrorCodes`.
+
+## 日本語
+
+- **安定したコマンドエラーコード分類を完全に文書化しました (#4644)** — USER_GUIDE の日本語エラーコード表に E015–E017 を追加し、両言語の表と `CommandErrorCodes` の同期を契約テストで維持します。

tests/CodeIndex.Tests/DocumentationDriftTests.cs

@@ -1,4 +1,6 @@
+using System.Reflection;
 using System.Text.RegularExpressions;
+using CodeIndex.Cli;
 using CodeIndex.Database;
 
 namespace CodeIndex.Tests;
@@ -21,6 +23,10 @@ public sealed class DocumentationDriftTests
         @"`(?:[A-Z_][A-Z0-9_]*=\S+\s+)*(?<prefix>cdidx|dotnet\s+\./src/CodeIndex/bin/Debug/net8\.0/cdidx\.dll|dotnet\s+run\s+--project\s+src/CodeIndex\s+--)\s+(?<token>[^\s`|;&]+)[^`]*`",
         RegexOptions.Compiled);
 
+    private static readonly Regex ErrorCodeTableRowRegex = new(
+        @"^\| `(?<code>E[0-9]{3}_[A-Z0-9_]+)` \|",
+        RegexOptions.Compiled | RegexOptions.Multiline);
+
     private static readonly HashSet<string> KnownCdidxEntrypointTokens = new(StringComparer.Ordinal)
     {
         "--completions",
@@ -153,6 +159,24 @@ public void PreparedCommandCacheDefault_DocumentationMatchesRuntime()
         Assert.Equal(2, content.Split(documentedRow, StringSplitOptions.None).Length - 1);
     }
 
+    [Fact]
+    public void UserGuide_ErrorCodeTablesMatchCommandErrorCodes_Issue4644()
+    {
+        var content = RepositoryTestPaths.ReadNormalizedText("USER_GUIDE.md");
+        var expectedCodes = typeof(CommandErrorCodes)
+            .GetFields(BindingFlags.Public | BindingFlags.Static)
+            .Where(field => field.IsLiteral && field.FieldType == typeof(string))
+            .Select(field => (string)field.GetRawConstantValue()!)
+            .Order(StringComparer.Ordinal)
+            .ToArray();
+
+        var englishCodes = ExtractErrorCodesFromSection(content, "### Error codes", "### Debugging reader errors");
+        var japaneseCodes = ExtractErrorCodesFromSection(content, "### エラーコード", "### reader エラーのデバッグ");
+
+        Assert.Equal(expectedCodes, englishCodes);
+        Assert.Equal(expectedCodes, japaneseCodes);
+    }
+
     [Theory]
     [InlineData("README.md", "## Quick Start", "## すぐに試す")]
     [InlineData("USER_GUIDE.md", "## Why cdidx", "## なぜ cdidx なのか")]
@@ -204,6 +228,22 @@ private static HashSet<string> ExtractWorkflowPathReferences(string relativePath
             .ToHashSet(StringComparer.Ordinal);
     }
 
+    private static string[] ExtractErrorCodesFromSection(string content, string heading, string nextHeading)
+    {
+        var sectionStart = content.IndexOf(heading, StringComparison.Ordinal);
+        if (sectionStart < 0)
+            throw new InvalidOperationException($"Missing documentation heading '{heading}'.");
+
+        var sectionEnd = content.IndexOf(nextHeading, sectionStart + heading.Length, StringComparison.Ordinal);
+        if (sectionEnd < 0)
+            throw new InvalidOperationException($"Missing documentation heading '{nextHeading}'.");
+
+        return ErrorCodeTableRowRegex
+            .Matches(content[sectionStart..sectionEnd])
+            .Select(match => match.Groups["code"].Value)
+            .ToArray();
+    }
+
     private static HashSet<string> ExtractWorkflowReadmeReferences(HashSet<string> workflowFileNames)
     {
         var content = RepositoryTestPaths.ReadText(".codex", "workflows", "README.md");