fail-kit 1.1.0

F.A.I.L. Kit Python Language Server for LangChain, CrewAI, and AutoGen

F.A.I.L. Kit Python LSP Server

A Language Server Protocol (LSP) implementation for auditing Python AI agent code. Provides real-time diagnostics, code actions, and hover information for LangChain, CrewAI, and AutoGen frameworks.

Features

• Real-time Diagnostics: Detects missing receipts, unhandled errors, secret exposure, and more
• Framework Support: LangChain, CrewAI, AutoGen, and generic Python agent patterns
• Code Actions: Quick fixes for common issues (add try-catch, generate receipts)
• Hover Information: Contextual documentation for F.A.I.L. Kit rules

Installation

pip install failkit-lsp

Or from source:

cd middleware/python-lsp
pip install -e .

Usage

VS Code

Add to your settings.json:

{
  "failKit.pythonLsp.enabled": true,
  "failKit.pythonLsp.path": "failkit-lsp"
}

Neovim (with nvim-lspconfig)

local lspconfig = require('lspconfig')
local configs = require('lspconfig.configs')

if not configs.failkit_lsp then
  configs.failkit_lsp = {
    default_config = {
      cmd = { 'failkit-lsp' },
      filetypes = { 'python' },
      root_dir = lspconfig.util.root_pattern('pyproject.toml', 'setup.py', '.git'),
    },
  }
end

lspconfig.failkit_lsp.setup{}

Command Line

Run the server directly:

failkit-lsp --stdio

Or with TCP:

failkit-lsp --tcp --host 127.0.0.1 --port 2087

Supported Rules

Rule ID	Description	Severity
FK001	Missing Receipt for Tool Call	Error
FK002	Missing Error Handling	Warning
FK003	Secret Exposure	Error
FK004	Side-Effect Without Confirmation	Warning
FK005	LLM Call Missing Resilience	Info
FK006	Missing Provenance Metadata	Warning
FK007	Hardcoded Credential	Error
FK008	CrewAI Task Missing Error Handler	Warning
FK009	AutoGen Agent Missing Termination	Warning

Framework-Specific Detection

LangChain

• AgentExecutor.invoke() / .run() calls
• BaseTool subclasses without receipt generation
• @tool decorated functions
• Chain invocations without error handling

CrewAI

• Crew.kickoff() calls
• Task definitions without error handlers
• Agent configurations missing memory settings

AutoGen

• UserProxyAgent / AssistantAgent configurations
• initiate_chat() calls without termination conditions
• Function tool definitions

Configuration

Create a .failkit.yaml or failkit.config.json in your project root:

# .failkit.yaml
python:
  enabled: true
  severity_overrides:
    FK005: "warning"  # Downgrade resilience checks to warnings
  ignore_patterns:
    - "**/tests/**"
    - "**/migrations/**"
  frameworks:
    langchain: true
    crewai: true
    autogen: true

Development

# Install dev dependencies
pip install -e ".[dev]"

# Run tests
pytest

# Format code
black src tests
ruff check src tests

# Type check
mypy src

License

MIT License - see LICENSE file for details.