cc-lsp-plugin-repro

TL;DR

When multiple Claude Code LSP plugins declare interest in the same file
extension (e.g. both tsgo and graphql-lsp handle .ts files), only one
plugin is used — whichever is listed first in enabledPlugins wins. There
doesn't appear to be a way to have both plugins active for the same extension.

In practice, this means enabling the graphql-lsp plugin (listed first) causes
TypeScript files to be routed to graphql-lsp instead of tsgo, and TypeScript
intelligence is lost entirely. Reordering the plugins so tsgo is listed first
restores TypeScript intelligence, but then graphql-lsp never starts.

The expected behavior is that both plugins should be able to serve their
respective intelligence for .ts files simultaneously.

Prerequisites

• Claude Code
• Node.js and npm

Setup

1. Clone and install dependencies

git clone https://github.com/trevor-scheer/cc-lsp-plugin-repro.git
cd cc-lsp-plugin-repro
npm install

2. Install the graphql-lsp binary

Download the appropriate binary for your platform from the
graphql-analyzer-lsp releases
page (latest: v0.1.5).

For example, on macOS (Apple Silicon):

# Download and extract
curl -L https://github.com/trevor-scheer/graphql-analyzer/releases/download/graphql-analyzer-lsp%2Fv0.1.5/graphql-lsp-aarch64-apple-darwin.tar.xz | tar -xJ

# Move to a directory on your PATH
mv graphql-lsp /usr/local/bin/

# Verify
which graphql-lsp

Available platform binaries:

Reproducing the issue

The easiest way to reproduce is to let Claude do it. After completing the setup
steps above, run claude and ask:

guide me through the LSP plugin reproduction

Claude knows the full reproduction plan (defined in CLAUDE.md) and will walk
you through all three parts, validating each step along the way.

If you prefer to run the steps manually, follow the instructions below.

Manual reproduction

LSP servers do not start automatically when Claude Code launches — they only
start when Claude invokes the LSP tool. Each part verifies which servers start
by checking process counts before and after invoking the tool.

Part 1: tsgo works on its own

The repo ships with .claude/settings.json pre-configured with only tsgo
enabled:

{
  "enabledPlugins": {
    "graphql-lsp@graphql-analyzer": false,
    "tsgo@graphql-analyzer": true
  }
}

1. Run claude in the repo.
2. In a separate terminal, verify no Claude-owned tsgo is running yet:

   pgrep -fa tsgo

3. Ask Claude to invoke the LSP tool:

   use the LSP hover tool on src/index.ts line 1, character 11
   

4. Check processes again — tsgo should now be running. The hover should return
   TypeScript type info for the gql import (e.g. function gql(...): DocumentNode).

Part 2: enabling graphql-lsp breaks tsgo

1. Update .claude/settings.json — enable graphql-lsp, listed first:

   {
     "enabledPlugins": {
       "graphql-lsp@graphql-analyzer": true,
       "tsgo@graphql-analyzer": true
     }
   }

2. Restart Claude Code (/exit, then claude).
3. In a separate terminal, verify neither LSP is running yet:

   pgrep -fa tsgo
   pgrep -fa graphql-lsp

4. Ask Claude to invoke the LSP tool on the same position:

   use the LSP hover tool on src/index.ts line 1, character 11
   

5. Check processes again — graphql-lsp should be running, but tsgo should
   not be. The hover result will differ from Part 1 (no TypeScript type
   info). TypeScript intelligence is lost.

Part 3: plugin ordering determines the outcome

1. Update .claude/settings.json — keep both enabled, but list tsgo first:

   {
     "enabledPlugins": {
       "tsgo@graphql-analyzer": true,
       "graphql-lsp@graphql-analyzer": true
     }
   }

2. Restart Claude Code.
3. Verify neither LSP is running yet.
4. Ask Claude to invoke the LSP tool on the same position:

   use the LSP hover tool on src/index.ts line 1, character 11
   

5. Check processes — this time tsgo should be running and graphql-lsp should
   not be. The hover returns TypeScript type info again, same as Part 1.

This suggests the order of plugins in enabledPlugins determines which server
handles a given file extension — the first listed plugin appears to win, and
only one plugin is used per extension.

Repo structure

.claude/settings.json   # LSP plugin configuration
.graphqlrc.yml           # GraphQL language server config (schema + documents)
schema.graphql           # GraphQL schema
src/index.ts             # Sample file using graphql-tag
tsconfig.json            # TypeScript config