Add LSP shim for cdidx

.github/workflows/release.yml

@@ -903,7 +903,7 @@ jobs:
 
           cat > "$tap_dir/Formula/codeindex.rb" <<EOF
           class Codeindex < Formula
-            desc "CLI code indexing and MCP search for local repositories"
+            desc "CLI code indexing, MCP search, and LSP lookup for local repositories"
             homepage "${REPO_URL}"
             version "${VERSION}"
             license "FSL-1.1-ALv2"

INTEGRATION_POLICY.md

@@ -16,6 +16,7 @@ Allowed integrations include:
 - AI coding agents invoking `cdidx` through CLI commands;
 - AI coding agents invoking `cdidx mcp`;
 - IDE/editor extensions that discover or call a user-installed `cdidx`;
+- IDE/editor extensions that launch `cdidx lsp`;
 - IDE/editor extensions that provide configuration UI for official CodeIndex;
 - shell scripts, task runners, and CI jobs that run `cdidx`;
 - MCP client configuration files;
@@ -35,30 +36,32 @@ access:
 
 - your source code remains yours;
 - your index files remain yours;
-- search results, snippets, structured JSON, and MCP responses generated from
-  your own codebases remain yours;
+- search results, snippets, structured JSON, MCP responses, and LSP responses
+  generated from your own codebases remain yours;
 - CodeIndex does not claim ownership over your repositories or generated
   development context.
 
 ## API Surface and Library Use
 
-CodeIndex ships primarily as a **CLI and MCP server**. It does not publish a
-general-purpose library or SDK API for embedders.
+CodeIndex ships primarily as a **CLI, MCP server, and LSP shim**. It does not
+publish a general-purpose library or SDK API for embedders.
 
 - The stable, supported surfaces are the `cdidx` CLI (including its `--json`
-  output) and the `cdidx mcp` JSON-RPC interface. Versioning guarantees only
-  apply to those surfaces.
+  output), the `cdidx mcp` JSON-RPC interface, and the `cdidx lsp` stdio
+  Language Server Protocol interface. Versioning guarantees only apply to
+  those surfaces.
 - The `cdidx` NuGet package is published with `PackAsTool=true` and is intended
   to be installed as a .NET global tool, not added as an assembly reference.
 - Types that happen to be `public` on the `cdidx` assembly (for example DTOs in
   `CodeIndex.Database` / `CodeIndex.Models`, or readers such as
-  `CodeIndex.Database.DbReader`) exist to satisfy CLI and MCP composition. They
-  are **implementation details**, not a public library contract, and may
+  `CodeIndex.Database.DbReader`) exist to satisfy CLI, MCP, and LSP
+  composition. They are **implementation details**, not a public library
+  contract, and may
   change, move, or become `internal` in any release without a deprecation
   cycle.
 - Projects that need a programmatic interface should depend on the CLI's
-  `--json` output or on the MCP server, both of which are covered by the
-  changelog and the documented status contract.
+  `--json` output, the MCP server, or the LSP shim, each of which is covered by
+  the changelog and documented integration contract.
 - The extractor plugin interfaces under `CodeIndex.Indexer.Extensibility` are
   a narrow exception for language-extension DLLs loaded by `cdidx` itself from
   `.cdidx/plugins` or `~/.cdidx/plugins`. They are not a general embedding API.

README.md

@@ -12,12 +12,12 @@
 ![License](https://img.shields.io/badge/License-FSL--1.1--ALv2-orange)
 ![SQLite](https://img.shields.io/badge/SQLite-FTS5-003B57?logo=sqlite&logoColor=white)
 
-**CLI code indexing and MCP search for local repositories.**
+**CLI code indexing, MCP search, and LSP editor lookup for local repositories.**
 
-`cdidx` is a command-line code indexer and MCP server that builds a local
-SQLite index of your repository so humans and AI agents can run fast
-full-text, symbol, dependency, and inspection queries without repeatedly
-rescanning the same tree.
+`cdidx` is a command-line code indexer, MCP server, and read-only LSP shim that
+builds a local SQLite index of your repository so humans, AI agents, and
+LSP-native editors can run fast full-text, symbol, dependency, and inspection
+queries without repeatedly rescanning the same tree.
 
 ## Why cdidx
 
@@ -56,6 +56,7 @@ cdidx definition UserService
 cdidx search "Handle" --project MyApp
 cdidx validate
 cdidx mcp
+cdidx lsp --db .cdidx/codeindex.db
 ```
 
 Custom language loops can stay out of tree: put extension aliases in
@@ -136,11 +137,11 @@ downgrading `cdidx`.
 
 | Area | What cdidx provides |
 |---|---|
-| Search surfaces | CLI-first output for humans and machines; full-text, symbol, reference, caller/callee, dependency, map, inspect, and excerpt commands. `search`, `definition`, `references`, `callers`, `callees`, `find`, and `validate` support `--format count|compact|csv|tsv|lsp|qf|sarif` for token-budgeted agents, scripts, editors, and CI reports. |
+| Search surfaces | CLI-first output for humans and machines; full-text, symbol, reference, caller/callee, dependency, map, inspect, and excerpt commands. `search`, `definition`, `references`, `callers`, `callees`, `find`, and `validate` support `--format count|compact|csv|tsv|lsp|qf|sarif` for token-budgeted agents, scripts, editors, and CI reports. `cdidx lsp --db .cdidx/codeindex.db` starts a read-only stdio Language Server Protocol shim for LSP-native editors. |
 | Definition and impact diagnostics | `definition --json` includes C# `disambiguator` hints for overloads, partial types, and extension receivers when indexed metadata can distinguish them. `impact --json` and MCP `impact_analysis` include `impact_failure_chain` and `suggestion_type` for zero-result routing; `impact --strict` exits non-zero when resolution or graph preconditions are unmet. |
 | Ranking and filters | Public/exported symbol matches rank ahead of protected, internal, and private matches. Use `--no-visibility-rank` for legacy order, and `--visibility` / `--exclude-visibility` with `symbols`, `definition`, `unused`, and `hotspots`. Query defaults can be adjusted with `CDIDX_DEFAULT_LIMIT`, `CDIDX_DEFAULT_SNIPPET_LINES`, and `CDIDX_DEFAULT_MAX_LINE_WIDTH`; explicit CLI flags still win. |
 | Project scoping | `.sln` / `.csproj`-aware <code>--project &lt;name&#124;path&gt;</code> filters for indexing and queries, plus `--solution <path>` when a workspace has multiple solution files. |
-| MCP integration | MCP server support for AI clients such as Claude Code, Cursor, and Windsurf, including tools, indexed-file resources, starter prompts, schema constraints for local argument validation, `mimeType` on text content blocks, logging, a structured `ping` health result, HTTP `GET /healthz`, opt-in HTTP `/events` keep-alive notifications, a compatibility server-side `notifications/initialized` ready signal on stdio or HTTP `/events` streams, and `Language support:` descriptions sourced from the same registries as `cdidx languages`. Tool schemas reject unknown arguments with `-32602`, advertise `x-stability`, and use snake_case structured JSON keys to match the CLI JSON contract. |
+| MCP/LSP integration | MCP server support for AI clients such as Claude Code, Cursor, and Windsurf, including tools, indexed-file resources, starter prompts, schema constraints for local argument validation, `mimeType` on text content blocks, logging, a structured `ping` health result, HTTP `GET /healthz`, opt-in HTTP `/events` keep-alive notifications, a compatibility server-side `notifications/initialized` ready signal on stdio or HTTP `/events` streams, and `Language support:` descriptions sourced from the same registries as `cdidx languages`. Tool schemas reject unknown arguments with `-32602`, advertise `x-stability`, and use snake_case structured JSON keys to match the CLI JSON contract. LSP mode exposes `initialize`, `workspace/symbol`, `textDocument/documentSymbol`, `textDocument/definition`, and `textDocument/references` over stdio for editors that do not speak MCP. |
 | Freshness | Parallel full-scan extraction with `--parallelism`, incremental refreshes with `--files` and `--commits`, continuous `--watch`, exact `status --check`, and configurable stale thresholds via `--stale-after` / `CDIDX_STALE_AFTER`. |
 | Storage | Local-first `.cdidx/codeindex.db` storage. Query commands run from nested directories prefer the outermost ancestor `.cdidx/codeindex.db` before falling back to the current directory. `--data-dir <dir>`, `CDIDX_DATA_DIR`, or `XDG_DATA_HOME` can move default SQLite storage outside the workspace; explicit `--db <path>` still wins. |
 | DB maintenance | New indexes use SQLite incremental auto-vacuum. `cdidx vacuum` reclaims free pages from existing DBs, including a one-time full `VACUUM` conversion for legacy no-autovacuum DBs, and `status --json` reports metrics under `db_pragma_settings`. |
@@ -275,12 +276,12 @@ details.
 ![License](https://img.shields.io/badge/License-FSL--1.1--ALv2-orange)
 ![SQLite](https://img.shields.io/badge/SQLite-FTS5-003B57?logo=sqlite&logoColor=white)
 
-**ローカルリポジトリ向けの CLI コードインデックスと MCP 検索です。**
+**ローカルリポジトリ向けの CLI コードインデックス、MCP 検索、LSP editor lookup です。**
 
-`cdidx` はコマンドラインのコードインデクサー兼 MCP サーバーで、リポジトリの
-ローカル SQLite index を作成します。人間と AI エージェントは、同じツリーを
-何度も読み直さずに、高速な全文検索、シンボル、依存関係、inspect クエリを
-実行できます。
+`cdidx` はコマンドラインのコードインデクサー、MCP サーバー、read-only LSP shim で、
+リポジトリのローカル SQLite index を作成します。人間、AI エージェント、
+LSP-native editor は、同じツリーを何度も読み直さずに、高速な全文検索、
+シンボル、依存関係、inspect クエリを実行できます。
 
 ## なぜ cdidx なのか
 
@@ -319,6 +320,7 @@ cdidx definition UserService
 cdidx search "Handle" --project MyApp
 cdidx validate
 cdidx mcp
+cdidx lsp --db .cdidx/codeindex.db
 ```
 
 カスタム言語の開発ループは out-of-tree で回せます。拡張子 alias は
@@ -386,11 +388,11 @@ upgrade / downgrade 後はインストール済み補完 script を再生成し
 
 | 分野 | 内容 |
 |---|---|
-| 検索面 | CLI-first の人間向け / 機械処理向け出力。全文検索、シンボル、参照、caller/callee、依存関係、map、inspect、excerpt コマンドを提供します。 |
+| 検索面 | CLI-first の人間向け / 機械処理向け出力。全文検索、シンボル、参照、caller/callee、依存関係、map、inspect、excerpt コマンドを提供します。`cdidx lsp --db .cdidx/codeindex.db` は LSP-native editor 向けの read-only stdio Language Server Protocol shim を起動します。 |
 | definition / impact 診断 | `definition --json` は C# overload、partial type、extension receiver を区別できる場合に `disambiguator` を返します。`impact --json` と MCP `impact_analysis` は 0 件時の経路判断用に `impact_failure_chain` と `suggestion_type` を返し、`impact --strict` は解決または graph の前提条件が満たされない場合に非 0 で終了します。 |
 | 順位と filter | public/exported なシンボル一致を protected、internal、private より優先します。従来順は `--no-visibility-rank`、可視性の include / exclude は `symbols`、`definition`、`unused`、`hotspots` の `--visibility` / `--exclude-visibility` で指定できます。query 既定値は `CDIDX_DEFAULT_LIMIT`、`CDIDX_DEFAULT_SNIPPET_LINES`、`CDIDX_DEFAULT_MAX_LINE_WIDTH` で調整でき、明示 CLI flag が常に優先されます。 |
 | project scope | `.sln` / `.csproj` を使った <code>--project &lt;name&#124;path&gt;</code> filter で index と query を .NET project 配下へ絞り込めます。workspace に solution が複数ある場合は `--solution <path>` を指定します。 |
-| MCP 連携 | Claude Code、Cursor、Windsurf などの AI クライアント向け MCP server。tools、インデックス済みファイル resources、starter prompts、ローカル引数検証用の schema constraints、text content block の `mimeType`、logging、構造化された `ping` health result、HTTP `GET /healthz`、opt-in の HTTP `/events` keep-alive notification、stdio または HTTP `/events` stream 上の互換性用 server-side `notifications/initialized` ready signal、`cdidx languages` と同じ言語レジストリ由来の `Language support:` 説明を提供します。Tool schema は未知の引数を `-32602` で拒否し、`x-stability` を公開し、CLI JSON contract と一致する snake_case の structured JSON key を使います。 |
+| MCP/LSP 連携 | Claude Code、Cursor、Windsurf などの AI クライアント向け MCP server。tools、インデックス済みファイル resources、starter prompts、ローカル引数検証用の schema constraints、text content block の `mimeType`、logging、構造化された `ping` health result、HTTP `GET /healthz`、opt-in の HTTP `/events` keep-alive notification、stdio または HTTP `/events` stream 上の互換性用 server-side `notifications/initialized` ready signal、`cdidx languages` と同じ言語レジストリ由来の `Language support:` 説明を提供します。Tool schema は未知の引数を `-32602` で拒否し、`x-stability` を公開し、CLI JSON contract と一致する snake_case の structured JSON key を使います。LSP mode は MCP 非対応 editor 向けに `initialize`、`workspace/symbol`、`textDocument/documentSymbol`、`textDocument/definition`、`textDocument/references` を stdio で公開します。 |
 | freshness | `--parallelism` による parallel full-scan、`--files` / `--commits` による差分更新、`--watch` による継続更新、`status --check` による完全一致確認、`--stale-after` / `CDIDX_STALE_AFTER` による age threshold 上書きに対応します。 |
 | storage | `.cdidx/codeindex.db` に保存する local-first 設計。ネストしたディレクトリからの query コマンドは、current directory にフォールバックする前に最上位祖先の `.cdidx/codeindex.db` を優先します。既定の SQLite 保存先は `--data-dir <dir>`、`CDIDX_DATA_DIR`、`XDG_DATA_HOME` で workspace 外へ移せます。明示的な `--db <path>` は引き続き最優先です。 |
 | DB maintenance | 新規 index DB は SQLite incremental auto-vacuum を使います。成功した writer 実行は WAL を `TRUNCATE` checkpoint します。既存 DB は `cdidx vacuum` で free page を回収でき、legacy no-autovacuum DB は初回だけ full `VACUUM` で変換します。`cdidx db schema` は on-disk schema を出力し、`cdidx db prune --dry-run|--apply` は orphaned DB rows を検査・削除します。`status --json` は `db_pragma_settings` 配下に metrics を出力します。 |

USER_GUIDE.md

@@ -28,6 +28,7 @@ cdidx find "guard" --path src/Auth.cs
 cdidx deps --path src/           # File-level dependency graph
 cdidx suggestions list           # Review local AI feedback history
 cdidx mcp                        # Start MCP server for AI tools
+cdidx lsp --db .cdidx/codeindex.db  # Start read-only LSP server for editors
 ```
 
 78 languages supported. 24 registered MCP tools. Incremental updates. Zero config.
@@ -1734,6 +1735,14 @@ If the refs are not known, use `cdidx ./myproject --json` and verify with `cdidx
 
 cdidx includes a built-in **MCP (Model Context Protocol) server**. MCP is a standard protocol that lets AI coding tools communicate with external programs. When you run `cdidx mcp`, cdidx starts listening on stdin/stdout — your AI tool sends search requests as JSON, and cdidx returns results instantly from the pre-built index.
 
+### LSP Server (for LSP-native editors)
+
+`cdidx lsp --db .cdidx/codeindex.db` starts a read-only Language Server Protocol
+server over stdio. It reuses the existing CodeIndex database and exposes
+`initialize`, `workspace/symbol`, `textDocument/documentSymbol`,
+`textDocument/definition`, and `textDocument/references` for editors that can
+launch an arbitrary LSP command but do not speak MCP.
+
 Tool results include structured JSON in `structuredContent` plus a short text summary in `content`, so AI tools can parse typed data without scraping large text blocks.
 
 Capped MCP result tools report `truncated` and `more_available` in `structuredContent` when more rows exist than the requested `limit`, so clients can avoid treating a capped page as exhaustive.
@@ -2071,6 +2080,7 @@ cdidx find "guard" --path src/Auth.cs
 cdidx deps --path src/           # ファイル間依存グラフ
 cdidx suggestions list           # ローカルのAIフィードバック履歴を確認
 cdidx mcp                        # AIツール向けMCPサーバー起動
+cdidx lsp --db .cdidx/codeindex.db  # editor向けread-only LSPサーバー起動
 ```
 
 78言語対応。24 MCPツール。インクリメンタル更新。設定不要。
@@ -3767,6 +3777,14 @@ ref が分からない場合は `cdidx ./myproject --json` を使い、`cdidx st
 
 cdidxには**MCP（Model Context Protocol）サーバー**が組み込まれています。MCPは、AIコーディングツールが外部プログラムと通信するための標準プロトコルです。`cdidx mcp` を実行すると、cdidxがstdin/stdoutで待機し、AIツールからの検索リクエストをJSONで受け取り、構築済みインデックスから即座に結果を返します。
 
+### LSP サーバー（LSP-native editor 向け）
+
+`cdidx lsp --db .cdidx/codeindex.db` は read-only の Language Server Protocol
+サーバーを stdio で起動します。既存の CodeIndex database を再利用し、
+任意の LSP command を起動できるが MCP には対応していない editor 向けに
+`initialize`、`workspace/symbol`、`textDocument/documentSymbol`、
+`textDocument/definition`、`textDocument/references` を公開します。
+
 ツール結果は `structuredContent` に構造化JSON、`content` に短い要約テキストを返すため、AIツールは巨大なテキストをパースせずに型付きデータを扱えます。
 
 上限付きの MCP result tool は、要求した `limit` より多くの行がある場合に `structuredContent` へ `truncated` と `more_available` を返します。これにより、クライアントは上限で切られたページを網羅的な結果として扱わずに済みます。

changelog.d/unreleased/1650.added.md

@@ -0,0 +1,24 @@
+---
+category: added
+issues:
+  - 1650
+affected:
+  - src/CodeIndex/Cli/ProgramRunner.cs
+  - src/CodeIndex/Cli/ConsoleUi.cs
+  - src/CodeIndex/Lsp/LspServer.cs
+  - src/CodeIndex/CodeIndex.csproj
+  - tests/CodeIndex.Tests/LspServerTests.cs
+  - README.md
+  - USER_GUIDE.md
+  - INTEGRATION_POLICY.md
+  - docs/NUGET_README.md
+  - .github/workflows/release.yml
+---
+
+## English
+
+- **`cdidx lsp` starts a read-only Language Server Protocol shim (#1650)** — LSP-native editors can now launch `cdidx lsp --db .cdidx/codeindex.db` over stdio for workspace symbols, document symbols, definitions, and references without needing an MCP adapter.
+
+## 日本語
+
+- **`cdidx lsp` が read-only の Language Server Protocol shim を起動できるようになりました (#1650)** — LSP-native editor は MCP adapter なしで `cdidx lsp --db .cdidx/codeindex.db` を stdio 起動し、workspace symbol、document symbol、definition、reference を取得できます。