[BUG] LSP servers not loading due to race condition between LSP Manager initialization and plugin loading

[MarjovanLier]

Preflight Checklist

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

What's Wrong?

LSP servers configured via plugins are not loaded because the LSP Manager initializes before plugin loading completes. Debug logs show the LSP Manager completing with 0 servers, then plugins loading 52ms later.

The LSP Manager finishes at 08:57:37.373Z with 0 servers.
Plugins start loading at 08:57:37.425Z — 52ms too late.

Affected versions: 2.0.69 (broken), 2.0.67 (works)

Related issue: This appears to be the same async race condition pattern described in #10997 (SessionStart hooks don't execute on first run).

Reference: LSP plugin support context from https://www.reddit.com/r/ClaudeAI/comments/1otdfo9/

What Should Happen?

LSP Manager should detect and load LSP servers from all enabled plugins.

Debug logs should show:

• Plugins load first
• LSP Manager initializes after plugins are ready
• LSP servers from plugins are registered (e.g., "LSP notification handlers registered successfully for all 4 server(s)")

The LSP tool should then be available with the configured language servers.

Error Messages/Logs

08:57:37.371Z [DEBUG] [LSP MANAGER] initializeLspServerManager() called
08:57:37.373Z [DEBUG] LSP notification handlers registered successfully for all 0 server(s)
...
08:57:37.425Z [DEBUG] Loading plugin phpactor-lsp from source: "./phpactor-lsp"
08:57:37.425Z [DEBUG] Loading plugin intelephense-lsp from source: "./intelephense-lsp"
08:57:37.425Z [DEBUG] Loading plugin psalm-lsp from source: "./psalm-lsp"
08:57:37.425Z [DEBUG] Loading plugin phpstan-lsp from source: "./phpstan-lsp"

Steps to Reproduce

1. Install LSP plugins (e.g., from marketplace or local plugins with .lsp.json configuration)
2. Set ENABLE_LSP_TOOL=true in environment
3. Run Claude Code 2.0.69
4. Check debug logs at ~/.claude/debug/latest
5. Observe LSP Manager initializes with 0 servers before plugins load

Workaround: Downgrade to version 2.0.67 with claude update --version 2.0.67

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.67

Claude Code Version

2.0.69

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

No response

[monneyboi]

Confirming this is still present in 2.0.71.

Platform: Linux (Arch, 6.17.9-arch1-1)
Terminal: tmux

Debug log shows same pattern:

14:10:55.958Z [DEBUG] [LSP MANAGER] Starting async initialization (generation 1)
14:10:55.959Z [DEBUG] LSP notification handlers registered successfully for all 0 server(s)
14:10:55.968Z [DEBUG] Loading plugin lsp from source: "./lsp"

Plugin loads correctly, lspServers config is valid, but LSP manager has already completed initialization 10ms earlier.

[MariusWilsch]

Confirmed on 2.0.72

Platform: macOS Darwin 24.3.0
Working version: 2.0.67 ✓
Broken version: 2.0.72 ✗

Debug log (2.0.72)

14:30:15.580Z [DEBUG] LSP notification handlers registered successfully for all 0 server(s)
14:30:15.596Z [DEBUG] Loading plugin pyright-lsp from source: "./plugins/pyright-lsp"

16ms gap - LSP Manager completes before plugins load.

Verification

Tested pyright-lsp@claude-plugins-official plugin with ENABLE_LSP_TOOL=true:

Version	LSP Tool	Pyright Diagnostics
2.0.67	✓ Available	✓ 3 errors detected
2.0.72	✓ Available	✗ "No LSP server available for .py"

The LSP tool exists in 2.0.72, but no servers are registered due to the race condition.

Workaround

npx @anthropic-ai/claude-code@2.0.67 works as temporary solution.

[MariusWilsch]

Follow-up: Also confirmed broken in 2.0.73 (same behavior - LSP tool exists but 'No LSP server available for file type: .py').

[evanlouie]

Confirming it's still happening on 2.0.74 as well.

[MarjovanLier]

Seems they just released LSPs officially.

• https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md
• https://code.claude.com/docs/en/plugins-reference#lsp-servers
• https://code.claude.com/docs/en/plugins#add-lsp-servers-to-your-plugin

However, the race condition persists. Anyone else get it working?

[MarjovanLier]

Additional testing evidence from 2.0.74 (comment drafted by Claude Code, posted on behalf of Marjo)

Extensive testing confirms the race condition persists in 2.0.74, including with official Anthropic LSP plugins:

Official plugins tested:

• php-lsp@claude-plugins-official - same race condition
• pyright-lsp@claude-plugins-official - same race condition

2.0.74 race gap measurements:

00:42:03.401Z - [LSP MANAGER] initializeLspServerManager() called
00:42:03.405Z - LSP handlers registered for 0 server(s)
00:42:03.463Z - phpactor-lsp loads (58ms LATE)
00:42:03.466Z - php-lsp loads (61ms LATE)
00:42:04.132Z - pyright-lsp loads (727ms LATE)

New in 2.0.74: LSP Plugin Recommendation feature correctly detects installed plugins but servers still don't register:

[lspRecommendation] Skipping php-lsp@claude-plugins-official (already installed)
LSP Diagnostics: Checking registry - 0 pending

Configuration changes have no effect - tested with startupTimeout, maxRestarts, restartOnCrash, and loggingConfig options. The .lsp.json files are never read due to the race condition.

Confirmed broken versions: 2.0.69, 2.0.72, 2.0.73, 2.0.74
Last working version: 2.0.67

[xHeaven]

Can confirm, it's broken in 2.0.74, works in 2.0.67

[MariusWilsch]

They added it as an official release note today and still broken lol.