karellen-lsp-mcp: Instructions file for Claude Code

CLAUDE.md

karellen-lsp-mcp CLAUDE.md is an instructions file for Claude Code from karellen/karellen-lsp-mcp. It costs 1,637 tokens per session, scanned A, original, Apache-2.0.

Build and maintenance instructions for a Python MCP server that connects AI tools to language servers for structured code information. Language servers analyze code and expose features such as project and symbol information.

In plain words
What is it for?
Building and testing the server, diagnosing its daemon and language-server connections, and adding or updating language support.
Why use it?
They explain the architecture, dependencies, tests, and important components needed to change the bridge safely.

Instructions file for Claude Code

Written for Claude Code: SessionStart hook event. Also seen: mentions Claude Code.

This is karellen/karellen-lsp-mcp's own configuration. It tells Claude Code how to work on karellen-lsp-mcp itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything karellen-lsp-mcp configures →

Reuse

Borrowing it

Nothing to install: this file belongs to karellen/karellen-lsp-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/karellen/karellen-lsp-mcp/master/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/karellen/karellen-lsp-mcp

Made for: Claude Code.

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Per session 1,637 This file is loaded in full into every session.
When invoked 1,637 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.01637 $0.01637
Opus 5 $0.00818 $0.00818
Sonnet 5 $0.00327 $0.00327
Haiku 4.5 $0.00164 $0.00164

Measured 11d ago against content hash e268ed48cd51, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

karellen-lsp-mcp CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Project: karellen-lsp-mcp

MCP server bridging to LSP servers for structured code introspection. See README.md for architecture, supported languages, configuration, and tool documentation.

Build & Test

PyBuilder project. Python >= 3.10.

pyb                          # default task: analyze + publish
pyb run_unit_tests           # unit tests only
pyb run_integration_tests    # integration tests (requires clangd on PATH)

Dependencies: mcp, lsprotocol, filelock, platformdirs

Project Layout

src/main/python/karellen_lsp_mcp/
  server.py            # MCP stdio frontend (entry point: main())
  lsp_server.py        # LSP proxy frontend (entry point: main()) — polyglot LSP proxy
  daemon.py            # Persistent daemon, owns LSP servers and project registry
  daemon_client.py     # Async client connecting frontends to daemon via Unix socket
  lsp_client.py        # Async wrapper around a single LSP server subprocess (JSON-RPC 2.0)
  lsp_normalizer.py    # Pluggable adapter for LSP server quirks (clangd readiness, retries)
  lsp_adapter.py       # LSP adapters: bridge detection → LSP server config (per-language)
  detector.py          # Project autodetection: build systems, IDE metadata, source roots
  project_registry.py  # Refcounted registry: project_id → LspClient
  types.py             # Dataclass response types for MCP tools
.claude-plugin/
  plugin.json          # Plugin manifest (name, version, description)
.mcp.json              # MCP server configuration for the plugin
.lsp.json              # LSP server configuration: maps file extensions to languages for Claude Code native LSP
hooks/
  hooks.json           # SessionStart (prerequisites), PostToolUse (compiler error detection)
scripts/
  check-prerequisites.sh   # Checks karellen-lsp-mcp, clangd, jdtls availability
  detect-lsp-opportunity.sh # Detects compiler/build errors, suggests LSP tools
agents/
  lsp-investigator.md  # Autonomous agent for LSP-based code investigation
skills/
  lsp-register/SKILL.md    # Project registration skill
  lsp-investigate/SKILL.md # Code investigation skill
docs/
  c-cpp.md             # C/C++ integration: detection, clangd, compile_commands.json
  java-kotlin.md       # Java/Kotlin integration: detection, jdtls, Gradle/Maven
  python.md            # Python integration: detection, pyright, virtual environments
  rust.md              # Rust integration: detection, rust-analyzer, Cargo workspaces
src/unittest/python/       # Unit tests (mocked, no external deps)
src/integrationtest/python/ # Integration tests (need clangd)

Read the full file on GitHub · 123 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 123 lines · 1,637 tokens per session scan A e268ed48cd51

Subscribe to this mod's changes

karellen-lsp-mcp CLAUDE.md is an instructions file published in the GitHub repository karellen/karellen-lsp-mcp (2 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 1,637 tokens to every session, about $0.0082 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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