pfix 0.1.4

Self-healing Python — catches runtime errors, fixes code & dependencies via LLM + MCP

🔧 pfix

Self-healing Python — catches runtime errors and fixes source code + dependencies via LLM + MCP.

Features

• @pfix decorator — wrap any function; errors trigger automatic repair
• Fast dep fix — ModuleNotFoundError → instant pip/uv install (no LLM call)
• pipreqs scanning — project-wide import analysis for missing dependencies
• LLM code repair — sends error context to LLM (OpenRouter/LiteLLM) for intelligent fixes
• pip + uv — auto-detects uv for faster installs, falls back to pip
• MCP server — @mcp.tool() via FastMCP for IDE integration (Claude Code, Cursor, VS Code)
• Git auto-commit — optional auto-commit of fixes with configurable prefix
• Auto-restart — os.execv process restart after fix applied
• Interactive diff — unified diff with confirmation before applying
• Backup system — timestamped backups in .pfix_backups/
• Async support — @apfix for async functions

Installation

pip install pfix

# With MCP server support
pip install pfix[mcp]

# With git auto-commit
pip install pfix[git]

# Everything
pip install pfix[all]

Quick Start

# 1. Configure
cp .env.example .env
# Set OPENROUTER_API_KEY=sk-or-v1-...

# 2. Use in your code

from pfix import pfix

@pfix
def process_data(path):
    import pandas as pd                    # auto-installed if missing
    df = pd.read_csv(path)
    return df.groupby("category").sum()    # LLM fixes column errors

@pfix(retries=3, hint="Parses ISO dates from API", deps=["requests", "python-dateutil"])
def fetch_events(url: str):
    import requests
    from dateutil.parser import parse
    return [parse(e["ts"]) for e in requests.get(url).json()["events"]]

CLI

pfix run script.py              # Run with global exception hook
pfix run script.py --auto       # Auto-apply fixes
pfix run script.py --restart    # Restart process after fix
pfix check                      # Show config status
pfix deps scan                  # Scan for missing deps (pipreqs)
pfix deps install               # Install all missing deps
pfix deps generate              # Generate requirements.txt
pfix server                     # Start MCP server (stdio)
pfix server --http 3001         # Start MCP server (HTTP)

MCP Integration

pfix exposes tools via FastMCP for IDE integration:

Tool	Description
pfix_analyze	Analyze error → diagnosis + fix proposal
pfix_fix	Analyze + apply fix (with backup)
pfix_deps_scan	Scan for missing deps
pfix_deps_install	Install a package
pfix_deps_generate	Generate requirements.txt
pfix_edit_file	Write file content

Claude Code / VS Code setup

Add to your MCP config (.claude/mcp.json or VS Code settings):

{
  "mcpServers": {
    "pfix": {
      "command": "python",
      "args": ["-m", "pfix.mcp_server"]
    }
  }
}

Configuration

.env

Variable	Default	Description
OPENROUTER_API_KEY	—	Required
PFIX_MODEL	openrouter/anthropic/claude-sonnet-4	LLM model
PFIX_AUTO_APPLY	false	Auto-apply fixes
PFIX_AUTO_INSTALL_DEPS	true	Auto pip/uv install
PFIX_AUTO_RESTART	false	Restart after fix
PFIX_PKG_MANAGER	auto	pip or uv
PFIX_MAX_RETRIES	3	Max attempts
PFIX_DRY_RUN	false	Show only
PFIX_GIT_COMMIT	false	Auto-commit fixes
PFIX_GIT_PREFIX	pfix:	Commit prefix

pyproject.toml

[tool.pfix]
model = "openrouter/anthropic/claude-sonnet-4"
auto_apply = false
max_retries = 3

Programmatic

from pfix import configure

configure(
    auto_apply=True,
    pkg_manager="uv",
    git_auto_commit=True,
)

How It Works

@pfix decorated function
        │
        ▼
   Exception caught
        │
        ├── ModuleNotFoundError? → pip/uv install → retry
        │
        ▼
   ErrorContext built (traceback, source, vars, imports, pipreqs scan)
        │
        ▼
   LLM analysis (LiteLLM → OpenRouter)
        │
        ▼
   FixProposal (diagnosis, code, deps, confidence)
        │
        ├── Show diff → confirm (or auto-apply)
        ├── Create .pfix_backups/ backup
        ├── Apply fix to source
        ├── Git commit (optional)
        ▼
   Reload module → retry (or os.execv restart)

Dependencies

Package	Role
litellm	LLM proxy — OpenRouter, OpenAI, Anthropic, Ollama
python-dotenv	Load .env config
rich	Terminal UI (diffs, panels, tables)
pipreqs	Project import scanning
pathspec	Gitignore-aware file filtering
mcp	FastMCP server (optional)
gitpython	Git auto-commit (optional)
watchdog	File change watching (optional)

License

Licensed under Apache-2.0.

Licensed under Apache-2.0.

Licensed under Apache-2.0.

Licensed under Apache-2.0.

Apache 2.0 — Tom Sapletta / Softreck