anthropics
[BUG] LSP servers not loading due to race condition between LSP Manager initialization and plugin loading
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?
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
- Install LSP plugins (e.g., from marketplace or local plugins with
.lsp.jsonconfiguration) - Set
ENABLE_LSP_TOOL=truein environment - Run Claude Code 2.0.69
- Check debug logs at
~/.claude/debug/latest - 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
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.
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/[email protected] works as temporary solution.
Follow-up: Also confirmed broken in 2.0.73 (same behavior - LSP tool exists but 'No LSP server available for file type: .py').
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?
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 conditionpyright-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
just confirming, broken here on 2.0.74
cat ~/.claude/debug/latest | grep -i lsp | head -n 7
2025-12-20T12:48:55.961Z [DEBUG] [LSP MANAGER] initializeLspServerManager() called
2025-12-20T12:48:55.961Z [DEBUG] [LSP MANAGER] Created manager instance, state=pending
2025-12-20T12:48:55.961Z [DEBUG] [LSP MANAGER] Starting async initialization (generation 1)
2025-12-20T12:48:55.964Z [DEBUG] LSP server manager initialized successfully
2025-12-20T12:48:55.964Z [DEBUG] LSP notification handlers registered successfully for all 0 server(s)
2025-12-20T12:48:55.967Z [DEBUG] Loading plugin rust-analyzer-lsp from source: "./plugins/rust-analyzer-lsp"
2025-12-20T12:48:55.967Z [DEBUG] Using provided version for rust-analyzer-lsp@claude-plugins-official: 1.0.0
claude --version:
2.0.74 (Claude Code)
Found the issue. The LSP server manager's initialize function is essentially empty, it just returns immediately without doing anything. There's a separate function that properly loads LSP server configurations from enabled plugins, but this function is never called anywhere in the codebase.
why do the release notes announce the LSP function as being released if it is not working?
...
Version 2.0.74:
• Added LSP (Language Server Protocol) tool for code intelligence features like go-to-definition, find references, and hover documentation
...
same issue here, wonder if there anything we can do locally to make it work
@giovannirco as described in the second reply:
npx @anthropic-ai/[email protected] works as temporary solution.
I actually haven't done this, I'm just waiting - but it should work. Depending on how you installed you may need to do something slightly different? The key is pinning the version at 2.0.67.
Race Condition Confirmed: https://github.com/anthropics/claude-code/issues/14803#issuecomment-3684942251
so i dove into the problem and found that this is not a race condition, it's simply not implemented afaict (at least in 2.0.74, which is what's latest in nixpkgs), the function supposedly responsible for registering the LSPs simply returns for no good reason I can find. I made a patch for this against 2.0.74, but with some tweaks it should be possible to port this to other versions, the problem is that the minified function name may change. But hopefully this gives people some idea of what to do about it instead of shouting into the void and hoping someone will actually care that the newly announced feature doesn't actually work at all...
claude-code-2.0.74-lsp-not-found-fix.patch
also, i just have to say i find it silly that they release minified code, this stuff doesn't have to run in the browser, so what's the point other than to annoy people and make community contributions harder.
Thanks for the insights @manveru, I wonder what happened internally that the actual code was not released with the release.
