[codex] Add languages indexed and capability filters

USER_GUIDE.md

@@ -282,7 +282,7 @@ sections below show examples and option details for the most common workflows.
 | Analysis | `hotspots` | Rank high-impact symbols or statements by reference volume | `symbol_hotspots` |
 | Analysis | `validate` | Report encoding and line-ending issues in indexed files; U+FFFD rows include origin/severity metadata | `validate` |
 | Status | `status` | Show DB statistics, freshness, and readiness metadata | `status` |
-| Status | `languages` | List language extensions and symbol/graph capabilities | `languages` |
+| Status | `languages` | List language extensions and symbol/graph capabilities; add `--indexed-only` and `--capability graph|symbols|references` for workspace audits | `languages` |
 | Diagnostics | `db --integrity-check` | Run SQLite `PRAGMA integrity_check` against the DB | -- |
 | Diagnostics | `report --output <path>` | Build a redacted bug-report bundle | -- |
 | Feedback | `suggestions` | List, inspect, and export local suggestion history | -- |
@@ -1531,7 +1531,7 @@ The database reflects the working tree at the time of the last index. After swit
 
 ## Supported languages
 
-All indexed languages are searchable through FTS5. Rows with **Symbols = yes** also support structured queries by function, class, import, or language-specific symbol name.
+All indexed languages are searchable through FTS5. Rows with **Symbols = yes** also support structured queries by function, class, import, or language-specific symbol name. Use `cdidx languages --indexed-only --json` to list only languages present in the current DB, and add `--capability graph|symbols|references` to narrow the table to languages that support a specific structured capability.
 
 | Language | Extensions | Symbols |
 |---|---|:---:|
@@ -1627,9 +1627,11 @@ All indexed languages are searchable through FTS5. Rows with **Symbols = yes** a
 
 ### Language extraction matrix
 
-Use `cdidx languages --json` as the live capability probe. This matrix explains
-the common extraction behavior so users know when to trust structured commands
-and when to fall back to `search`.
+Use `cdidx languages --json` as the live capability probe. Add `--indexed-only`
+when you only want languages present in the current DB, and add
+`--capability graph|symbols|references` when auditing a specific structured
+capability. This matrix explains the common extraction behavior so users know
+when to trust structured commands and when to fall back to `search`.
 
 | Language family | Symbols | References / graph | Notes and example query |
 |---|---|---|---|
@@ -3820,7 +3822,9 @@ indexing はファイル単位の SQLite transaction を commit します。長
 ### 言語別 extraction matrix
 
 現在の capability は `cdidx languages --json` を live probe として確認してください。
-この matrix は、構造化 command を信頼できる場面と `search` に戻るべき場面を判断するための概要です。
+現在の DB に存在する言語だけを見たい場合は `--indexed-only`、特定の構造化 capability を監査する場合は
+`--capability graph|symbols|references` を追加します。この matrix は、構造化 command を信頼できる場面と
+`search` に戻るべき場面を判断するための概要です。
 
 | 言語ファミリ | Symbols | References / graph | メモと例 |
 |---|---|---|---|
@@ -4198,7 +4202,7 @@ OpenAI Codex CLI (`codex.json` または `~/.codex/config.json`):
 | `symbol_hotspots` | 影響の大きい hotspot を検索。`groupBy` は `symbol` / `file` / `statement` を指定でき、SQL scope は statement grouping、非 SQL scope は symbol grouping が既定。 |
 | `batch_query` | 複数クエリを1回で実行（MCP専用、最大10件）。レスポンスにはトップレベル `metadata`（`submitted` / `executed` / `errors` / `total_elapsed_ms` / `success_count` / `failure_count`）と各 `results` エントリの `request_index` / `ok` / `elapsed_ms` / `args_summary` が含まれ、位置だけに依存せず部分失敗や遅い内部クエリを把握できます。 |
 | `validate` | エンコーディング問題（origin/severity 付き U+FFFD、BOM、null バイト、改行混在 / CR-only 行末、UTF-16 BOM 検出、UTF-8 以外と推定されるエンコーディング）を報告 |
-| `languages` | 対応言語一覧を拡張子・機能付きで表示 |
+| `languages` | 対応言語一覧を拡張子・機能付きで表示。`--indexed-only` と `--capability graph|symbols|references` で現在の DB や機能別に絞り込み可能 |
 | `ping` | 軽量な接続確認 |
 | `index` | プロジェクトのインデックス作成・更新 |
 | `backfill_fold` | 既存 DB の folded-name key をソース再解析なしで更新 |

changelog.d/unreleased/3000.added.md

@@ -0,0 +1,18 @@
+---
+category: added
+issues:
+  - 3000
+affected:
+  - src/CodeIndex/Cli/QueryCommandRunner.cs
+  - src/CodeIndex/Cli/CliFlagSchema.cs
+  - src/CodeIndex/Cli/ConsoleUi.cs
+  - USER_GUIDE.md
+---
+
+## English
+
+- **`languages` can now filter by indexed languages and capability (#3000)** — `cdidx languages` accepts `--indexed-only` to show only languages present in the current database and `--capability graph|symbols|references` to narrow language audits to a specific structured capability.
+
+## 日本語
+
+- **`languages` が indexed language と capability で絞り込めるようになりました (#3000)** — `cdidx languages` は現在のデータベースに存在する言語だけを表示する `--indexed-only` と、特定の構造化 capability に絞る `--capability graph|symbols|references` を受け付けるようになりました。

src/CodeIndex/Cli/CliFlagSchema.cs

@@ -121,6 +121,7 @@ internal static class CliFlagSchema
     private static readonly string[] EntrypointConfidenceCommands = ["map"];
     private static readonly string[] MapSectionCommands = ["map"];
     private static readonly string[] DependencyCycleCommands = ["deps"];
+    private static readonly string[] LanguagesFilterCommands = ["languages"];
 
     // `--exact` is the legacy shorthand that every name-resolution command accepts.
     // `--exact` は名前解決系の全コマンドで受け付けるレガシー shorthand。
@@ -154,7 +155,7 @@ internal static class CliFlagSchema
     [
         "index", "backfill-fold", "optimize", "search", "definition", "goto", "references", "callers", "callees",
         "symbols", "files", "find", "excerpt", "map", "inspect", "outline", "status",
-        "validate", "deps", "impact", "unused", "hotspots", "db", "vacuum", "report", "batch", "mcp",
+        "validate", "deps", "impact", "unused", "hotspots", "languages", "db", "vacuum", "report", "batch", "mcp",
     ];
 
     private static readonly string[] WorkspaceDbCommands = ["deps"];
@@ -163,14 +164,14 @@ internal static class CliFlagSchema
     [
         "index", "search", "definition", "goto", "references", "callers", "callees",
         "symbols", "files", "find", "excerpt", "map", "inspect", "outline", "status",
-        "validate", "deps", "impact", "unused", "hotspots", "batch",
+        "validate", "deps", "impact", "unused", "hotspots", "languages", "batch",
     ];
 
     private static readonly string[] ReadOnlyDbCommands =
     [
         "search", "definition", "goto", "references", "callers", "callees",
         "symbols", "files", "find", "excerpt", "map", "inspect", "outline", "status",
-        "validate", "deps", "impact", "unused", "hotspots",
+        "validate", "deps", "impact", "unused", "hotspots", "languages",
     ];
 
     private static readonly string[] JsonCommands =
@@ -239,6 +240,8 @@ private static IReadOnlyList<CliFlag> BuildAll()
             new() { Name = "--min-entrypoint-confidence", ValuePlaceholder = "<0.0..1.0>", Description = "Map: omit entrypoint candidates below this confidence", Commands = Set(EntrypointConfidenceCommands) },
             new() { Name = "--sections", ValuePlaceholder = "<tree,languages,hotspots,metrics>", Description = "Map: comma-separated response sections to include", Commands = Set(MapSectionCommands) },
             new() { Name = "--cycles", Description = "Deps: return dependency cycles instead of edge rows", Commands = Set(DependencyCycleCommands) },
+            new() { Name = "--indexed-only", Description = "Languages: list only languages present in the current index", Commands = Set(LanguagesFilterCommands) },
+            new() { Name = "--capability", ValuePlaceholder = "<graph|symbols|references>", Description = "Languages: filter by language capability", Commands = Set(LanguagesFilterCommands) },
             new() { Name = "--query", ValuePlaceholder = "<query>", Description = "Literal query", Commands = Set(QueryCommands) },
             new() { Name = "--body", Description = "Include body", Commands = Set(BodyCommands) },
             new() { Name = "--exact", Description = "Backward-compatible exact shorthand", Commands = Set(ExactCommands) },

src/CodeIndex/Cli/ConsoleUi.cs

@@ -108,7 +108,7 @@ private static readonly (string Command, string Usage)[] CommandUsageLines =
         ("export", "cdidx export <archive> [--db <path>] [--json]"),
         ("export", "cdidx export ctags [--output <path>] [--db <path>]"),
         ("import", "cdidx import <archive> [--db <path>] [--prune-paths] [--json]"),
-        ("languages", "cdidx languages [--json]"),
+        ("languages", "cdidx languages [--db <path>] [--json] [--indexed-only] [--capability <graph|symbols|references>]"),
         ("batch", "cdidx batch [--db <path>]  # reads JSON string arrays from stdin, one query command per line; max 1,048,576 chars/line and 256 arguments"),
         ("mcp", "cdidx mcp [--db <path>] [--transport stdio|http] [--http-listen <host:port>] [--audit-log <path>] [--audit-log-include-values] [--audit-log-max-bytes <n>] [--suggestion-dedup-threshold <0..1>]"),
         ("lsp", "cdidx lsp [--db <path>]"),