[BUG] LSP tool passes `rootUri: null` during initialization, breaking TypeScript Language Server on Windows

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Environment

• Claude Code: v2.1.70
• OS: Windows 11
• Shell: PowerShell 7.5.4 / Git Bash (MSYS2)
• Node manager: mise
• Node.js: v24.14.0
• typescript-language-server: v5.1.3
• TypeScript: v5.9.3
• Project: Next.js 15

Bug Description

Claude Code's LSP tool sends rootUri: null in the LSP initialize request when spawning typescript-language-server. Without a workspace root, the server cannot locate the project's tsconfig.json or node_modules/typescript, causing it to crash immediately:

What Should Happen?

Request initialize failed with message: Could not find a valid TypeScript installation.
Please ensure that the "typescript" dependency is installed in the workspace
or that a valid tsserver.path is specified. Exiting.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Install typescript-language-server globally (via mise .exe shims on Windows)
2. Open a TypeScript/Next.js project in Claude Code
3. Ask Claude Code to perform any LSP operation (e.g., "find all references to the Event type, using LSP")
4. Observe: server crashes with "Could not find a valid TypeScript installation"

Verification

I manually tested the LSP initialize request with both rootUri: null and the correct workspace URI:

| rootUri value | Result |
|---|---|
| null | Server crashes — cannot find TypeScript |
| "file:///C:/Users/.../cdsc" | Server initializes successfully, finds TypeScript 5.9.3 |

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.70

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_