Language Server Protocol (LSP)

The Language Server Protocol (LSP) is an open, JSON-RPC-based protocol for communication between code editors and language servers. Originally developed by Microsoft for VS Code, it has since become an industry standard.

Claude Code natively supports LSP, giving Claude the same intelligent code capabilities as a professional IDE while processing your code.

What Does LSP Bring to Claude Code?

Through LSP integration, Claude gains the following capabilities:

Feature	Description
Real-time diagnostics	Claude sees errors and warnings immediately after every edit
Go to definition	Quickly locate where a function, variable, or class is defined
Find references	Find all usages of a code symbol across the project
Hover information	Get type information and documentation comments
Language awareness	Understand the type and context of code symbols

LSP is a native plugin feature of Claude Code — it does not depend on VS Code or any other IDE. You can use Claude Code independently in a terminal and enjoy full code intelligence support.

How It Works

┌─────────────────┐     LSP Protocol      ┌──────────────────────┐
│   Claude Code   │ ◄──────────────────► │  Language Server     │
│   (client)      │    JSON-RPC           │  (e.g. typescript-   │
│                 │                       │   language-server)   │
└─────────────────┘                       └──────────────────────┘
         │                                          │
         │                                          │
         ▼                                          ▼
  Sends code action requests               Analyzes code and returns results
  (go to definition, find references…)    (locations, types, errors…)

Once you install and enable an LSP plugin:

On startup: Claude Code automatically starts the language servers configured in installed plugins
On edit: The language server analyzes your code in real time after every file change
Diagnostics: Errors and warnings are automatically fed back to Claude
Navigation: Claude can use go-to-definition, find-references, and other operations

Installing LSP Plugins

Install from the Official Marketplace (Recommended)

The easiest approach is to install from the official plugin marketplace:

# Run inside Claude Code
/plugin
# Then select the Discover tab and search for "lsp"

Officially Supported LSP Plugins

Plugin	Language Server	Installation
`pyright-lsp`	Pyright (Python)	`pip install pyright` or `npm install -g pyright`
`typescript-lsp`	TypeScript Language Server	`npm install -g typescript-language-server typescript`
`rust-lsp`	rust-analyzer	See installation guide

⚠️

LSP plugins are configuration files only — they do not include the language server binary itself. You must install the corresponding language server first, then install the plugin.

LSP Plugin Configuration Format

If the official marketplace doesn’t have the language you need, you can create your own LSP plugin.

Configuration File Location

Standalone file: .lsp.json in the plugin root directory
Inline configuration: in the lspServers field of plugin.json

Configuration Example

{
  "typescript": {
    "command": "typescript-language-server",
    "args": ["--stdio"],
    "extensionToLanguage": {
      ".ts": "typescript",
      ".tsx": "typescriptreact",
      ".js": "javascript",
      ".jsx": "javascriptreact"
    }
  }
}

Required Fields

Field	Description
`command`	LSP binary name (must be on your PATH)
`extensionToLanguage`	Mapping of file extensions to language identifiers

Optional Fields

Field	Description
`args`	Command-line arguments for starting the language server
`transport`	Communication mode: `stdio` (default) or `socket`
`env`	Environment variables to set when starting the server
`initializationOptions`	Options passed to the server during initialization
`settings`	Settings sent via `workspace/didChangeConfiguration`
`workspaceFolder`	Workspace folder path
`startupTimeout`	Maximum time to wait for server startup (milliseconds)
`shutdownTimeout`	Maximum time to wait for graceful shutdown (milliseconds)
`restartOnCrash`	Whether to automatically restart the server on crash
`maxRestarts`	Maximum restart attempts before giving up
`loggingConfig`	Debug logging configuration

Debugging LSP Issues

If you encounter LSP-related problems, enable verbose logging:

claude --enable-lsp-logging

Log files are located in the ~/.claude/debug/ directory.

Common Issues

“Executable not found in $PATH”

The language server is not installed or is not on your system PATH. Install the corresponding language server first.

“No LSP server available for file type”

No LSP plugin is configured for that file type. Check that the plugin is correctly installed and that extensionToLanguage includes the extension in question.

Available LSP Plugins

Full code intelligence support for TypeScript/JavaScript projects

TypeScript LSP

Reference Resources

Claude Code Official Plugin Documentation
boostvolt/claude-code-lsps — Community-maintained LSP plugin collection
Language Server Protocol Official Specification

Skills First Principles Deep Dive TypeScript LSP