@harms-haus/code-lens

LSP-powered code intelligence CLI.

Manage LSP servers from the command line. Get diagnostics, find references, navigate code, and more — without managing LSP servers yourself.

Installation

npm install -g @harms-haus/code-lens

Quick Start

# Get diagnostics for a file
code-lens diagnostics --file=src/index.ts

# Find all references to a symbol
code-lens find-references --file=src/index.ts --line=10 --col=5

# Get type info at a position
code-lens hover --file=src/index.ts --line=10 --col=5

# Check daemon status
code-lens status

Documentation

• Architecture — System design and data flow
• Commands — Full command reference
• Daemon Protocol — Client-daemon communication spec
• Adding Languages — Guide to adding LSP server support
• Contributing — Development setup and PR process

Supported Languages

code-lens auto-detects the language from file extensions and starts the appropriate LSP server. LSP servers must be installed separately — the CLI will tell you how if one is missing.

| Language | Extensions | LSP Server | Install | |----------|-----------|------------|---------| | TypeScript / JavaScript | .ts .tsx .js .jsx .mjs .cjs | typescript-language-server | npm install -g typescript-language-server typescript | | Python | .py | pylsp | pip install python-lsp-server | | Rust | .rs | rust-analyzer | rustup component add rust-analyzer | | Go | .go | gopls | go install golang.org/x/tools/gopls@latest | | Java | .java | Eclipse JDT LS | eclipse-jdtls/eclipse.jdt.ls | | C / C++ | .c .cpp .cc .cxx .h .hpp .hxx | clangd | apt install clangd / brew install llvm | | C# | .cs | OmniSharp | dotnet tool install -g omnisharp | | PHP | .php | intelephense | npm install -g intelephense | | Ruby | .rb | ruby-lsp | gem install ruby-lsp | | Lua | .lua | lua-language-server | npm install -g lua-language-server | | HTML | .html .htm | html-languageserver | npm install -g vscode-html-languageserver-bin | | CSS / SCSS / LESS | .css .scss .less | css-languageserver | npm install -g vscode-css-languageserver-bin | | JSON | .json .jsonc | json-languageserver | npm install -g vscode-json-languageserver-bin | | YAML | .yaml .yml | yaml-language-server | npm install -g yaml-language-server | | Markdown | .md | markdown-language-server | npm install -g vscode-markdown-languageserver | | Dart | .dart | Dart analysis server | dart.dev/get-dart | | Kotlin | .kt .kts | kotlin-language-server | fwcd/kotlin-language-server | | Swift | .swift | sourcekit-lsp | Included with Swift ≥ 5.6 | | Zig | .zig | zls | zigtools/zls | | Haskell | .hs .lhs | haskell-language-server | ghcup install hls | | OCaml | .ml .mli | ocamllsp | opam install ocaml-lsp-server | | Elixir | .ex .exs | elixir-ls | elixir-lsp/elixir-ls | | Scala | .scala .sbt | Metals | cs install metals | | Terraform / HCL | .tf .tfvars .hcl | terraform-ls | hashicorp/terraform-ls | | Dockerfile | .dockerfile Dockerfile | dockerfile-language-server | npm install -g dockerfile-language-server-nodejs | | SQL | .sql | sql-language-server | npm install -g sql-language-server | | Vue | .vue | vue-language-server | npm install -g @vue/language-server @vue/typescript-plugin typescript | | Svelte | .svelte | svelte-language-server | npm install -g svelte-language-server | | TOML | .toml | taplo | npm install -g @taplo/lsp | | Nix | .nix | nil | nix profile install nixpkgs#nil | | LaTeX | .tex .latex | texlab | cargo install texlab | | R | .r .R | R languageserver | R -e 'install.packages("languageserver")' | | Bash / Shell | .sh .bash | bash-language-server | npm install -g bash-language-server |

Library Usage

@harms-haus/code-lens can also be used as a library — not just a CLI tool. Import it into your own Node.js project to start a daemon, send requests, and process results programmatically.

Subpath Exports

| Import path | Description | |---|---| | @harms-haus/code-lens | Re-exports all client functions | | @harms-haus/code-lens/client | Daemon client — sendRequest, ensureDaemon, stopDaemon, getSocketPath, languageFromPath, and more (see below) | | @harms-haus/code-lens/lsp | Direct LSP access — LspManager, LspClient, language config utilities |

Quick Start

import { ensureDaemon, sendRequest, getSocketPath } from "@harms-haus/code-lens/client";

// Start the daemon (no-op if already running)
await ensureDaemon(process.cwd());

// Send a JSON-RPC request
const socketPath = getSocketPath(process.cwd());
const result = await sendRequest(socketPath, {
  jsonrpc: "2.0",
  method: "fullCheck",
  params: {
    files: ["src/index.ts"],
    config: { prettier: true, linters: true, lsp: true },
  },
  id: 1,
});

// result is a CommandResult: { content, details, isError }
if (result.isError) {
  console.error("Check failed:", result.content[0].text);
} else {
  console.log(result.content[0].text);
  // details.statuses, details.hasIssues, details.durationMs, etc.
}

Client Exports (@harms-haus/code-lens/client)

| Export | Kind | Description | |---|---|---| | sendRequest | function | Send a JSON-RPC request to the daemon over a Unix socket | | ensureDaemon | function | Start a daemon if none is running; restart on version mismatch | | startDaemon | function | Spawn a new daemon process | | stopDaemon | function | Stop the running daemon for a given cwd | | isDaemonRunning | function | Check whether a daemon is active | | getSocketPath | function | Resolve the socket path for a cwd | | getMetadataPath | function | Resolve the daemon metadata file path | | languageFromPath | function | Detect language from a file extension | | isServerInstalled | function | Check whether the LSP server for a language is available | | probeSocket | function | Probe a Unix socket to check if a daemon is listening | | ok / err | functions | Build CommandResult success/error values | | DaemonRequest | type | JSON-RPC request shape ({ jsonrpc, method, params, id }) | | DaemonResponse | type | JSON-RPC response shape | | DaemonMetadata | type | Daemon metadata persisted to disk ({ pid, socketPath, version, cwd }) | | CommandResult | type | { content, details, isError } | | DAEMON_ERROR_CODES | const | Standard error codes (SERVER_NOT_FOUND, FILE_NOT_FOUND, …) | | DAEMON_VERSION | const | Current daemon protocol version |

Available Daemon Methods

These are the method values you can pass in a DaemonRequest:

| Method | Description | |---|---| | fullCheck | Run all checks (formatters, linters, LSP diagnostics) concurrently | | diagnostics | Get LSP diagnostics for files | | fileChanged | Notify the daemon that files have changed | | lint | Run configured linters | | prettier | Check formatting via the formatter system | | fix | Run formatter and linter fix modes (writes to disk) | | hover | Get type info at a position | | find-references | Find all references to a symbol | | find-definition | Go to definition | | find-type-definition | Go to type definition | | find-implementations | Find implementations of an interface/type | | find-symbols | Workspace symbol search | | find-document-symbols | Document symbols for a file | | find-calls | Incoming/outgoing call hierarchy | | find-type-hierarchy | Supertype/subtype hierarchy | | rename-symbol | Rename a symbol across the workspace | | status | Daemon and LSP server status |

LSP Direct Access (@harms-haus/code-lens/lsp)

Use this subpath when you need direct control over LSP servers without the daemon layer:

import { LspManager, LspClient, languageFromPath } from "@harms-haus/code-lens/lsp";

const manager = new LspManager(process.cwd());
const client: LspClient | null = await manager.getClientForFile("src/index.ts");
if (!client) process.exit(1);
const hover = await client.hover("file:///path/to/src/index.ts", 9, 4);

Key exports: LspManager, LspClient, DEFAULT_IDLE_TIMEOUT_MS, languageFromPath, isServerInstalled, and related types (LspServerConfig, ServerStatus, LspServerInstance, LspManagerState).

Requirements

• Node.js >= 20.0.0
• LSP servers must be installed separately — the CLI will display an install command if the required server is missing

License

MIT