Claude Code Tips

Language Server Support

Claude Code has a built-in LSP tool that gives it semantic understanding of your code. Instead of pattern-matching with grep, Claude can jump to definitions, find all references, trace call hierarchies, and see type errors — the same capabilities your editor has.

What Claude gets from LSP

Operation	What it does
Go to Definition	Jump to where a symbol is defined
Find References	Find every usage of a symbol
Hover	Get type info and docs for a symbol
Document Symbols	List all functions, classes, and variables in a file
Workspace Symbols	Search for symbols across the entire project
Go to Implementation	Find concrete implementations of interfaces
Call Hierarchy	Trace which functions call (or are called by) a given function

After every file edit, the language server also pushes diagnostics back to Claude automatically — type errors, missing imports, undefined variables. Claude sees and fixes these in the same turn without running a compiler.

The plugins are just config files

The Claude plugin marketplace lists language server plugins for TypeScript, Python, Go, Rust, and others. They look fancy but they're minimal — each one is basically a README and a small JSON config that tells Claude which binary to run and which file extensions to associate.

Here's what the TypeScript plugin's config boils down to:

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

That's it. It points at a binary and maps file extensions.

Setup

1. Install the language server binary

The plugin doesn't bundle the server — you need the actual binary on your system. For TypeScript:

npm install -g typescript-language-server typescript

2. Install the plugin from the marketplace

Inside Claude Code, run:

/plugin install typescript-lsp@claude-plugins-official

Or interactively: run /plugin, go to the Discover tab, search "typescript", and install.

3. Restart Claude Code

The LSP server initializes at startup. After installing, restart your session.

Why TypeScript matters most

TypeScript is the highest-value language server for Claude Code because:

Augur projects are TypeScript — every app in this monorepo is Next.js + TypeScript
Type errors surface instantly — Claude sees type mismatches the moment it edits a file, before you ever run tsc
Refactoring gets reliable — renaming a type or changing a function signature? Claude finds all real references, not just text matches
Import resolution works — Claude knows what's exported from each module instead of guessing

Other language servers

The same pattern works for any language. Install the binary, install the plugin:

Language	Binary	Install
TypeScript	`typescript-language-server`	`npm i -g typescript-language-server typescript`
Python	`pyright-langserver`	`pip install pyright` or `npm i -g pyright`
Go	`gopls`	`go install golang.org/x/tools/gopls@latest`
Rust	`rust-analyzer`	`rustup component add rust-analyzer`
PHP	`intelephense`	`npm i -g intelephense`

Community marketplaces like boostvolt/claude-code-lsps extend coverage to 20+ languages including Ruby, Elixir, Dart, and Zig.

Troubleshooting

"Executable not found in $PATH" — the binary isn't installed or isn't in your shell's PATH. Check with which typescript-language-server.
High memory usage — servers like rust-analyzer and pyright can be heavy on large projects. Close and reopen Claude Code if it gets sluggish.
No diagnostics showing — make sure the plugin is enabled. Run /plugin and check the Installed tab.

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