reforge-mcp

An MCP server that connects Claude Code to your codebase and systematically cleans it up — scanning, planning, and applying fixes with full rollback safety.

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What it does

Vibe-coded repos accumulate fast: functions nobody calls, copy-pasted logic in three files, one 900-line god module that does everything, circular imports that break at runtime. Spotting this manually takes hours; fixing it safely takes longer. reforge-mcp exposes your codebase to Claude Code as a set of structured tools so it can analyse, prioritise, and apply fixes autonomously — one atomic commit at a time.

The 7 MCP tools

Tool	What it does
scan_repo	AST-parses your repo (Python, JS, TS, Go) and returns dead code, duplicates, god files, circular deps, and monorepo subprojects
get_chunk	Reads an exact line-range slice from any file — lets Claude fetch only what it needs without blowing its context window
write_fix	Applies a unified diff atomically, runs optional tests, and auto-rolls back on failure
git_commit	Stages and commits specific files; enforces a per-session budget and confirmation checkpoints
read_memory	Reads a value from reforge-state.json — persists architecture hypotheses, pending fixes, and embeddings across sessions
write_memory	Writes any value atomically to reforge-state.json
get_health_score	Computes a 0–100 health score from scan metrics and appends a timestamped entry to the project's health history

Also included

• Health score trending — every get_health_score call appends to health_history so you can chart improvement over time
• Persistent memory — reforge-state.json survives across Claude Code sessions; stores architecture hypotheses, fix logs, pending work
• Monorepo support — scan_repo detects Python, JavaScript, TypeScript, and Go subprojects from their marker files and returns the correct test_command per subproject
• Changelog generation — REFORGE_CHANGES.md is written on demand with score deltas, applied fixes, and pending items

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Installation

Prerequisites: Python 3.11+, Claude Code CLI, Git

From PyPI (recommended)

pip install reforge-mcp

From source

# 1. Clone the repo
git clone https://github.com/codewithaiyan/reforge-mcp.git
cd reforge-mcp

# 2. Create and activate a virtual environment
python3 -m venv venv
source venv/bin/activate          # Windows: venv\Scripts\activate

# 3. Install in editable mode
pip install -e .

# Find the absolute path to the server entry point
which reforge-mcp                 # e.g. /home/you/.local/bin/reforge-mcp

Add to claude_desktop_config.json (usually ~/.config/claude/claude_desktop_config.json on Linux, ~/Library/Application Support/Claude/claude_desktop_config.json on macOS):

{
  "mcpServers": {
    "reforge-mcp": {
      "command": "/home/you/reforge-mcp/venv/bin/reforge-mcp",
      "args": [],
      "env": {}
    }
  }
}

Replace the path with the output of which reforge-mcp from step 4.

# 5. Set your Anthropic API key (if not already set)
export ANTHROPIC_API_KEY=sk-ant-...

Restart Claude Code. The seven tools will appear under the MCP panel.

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Usage

Example session with Claude Code

You: Use reforge-mcp to scan my repo at /home/me/myproject and fix the top issues.

Claude: I'll start with a full scan.

[calls scan_repo("/home/me/myproject")]

The scan found:
- 14 dead functions across 6 files
- 3 duplicate implementations of `calculate_discount`
- 1 god file: src/api/handlers.py (847 lines, 23 exports)
- 2 circular dependencies: auth → middleware → auth

Health score: 47/100

Let me fetch the duplicate implementations to confirm they're identical.

[calls get_chunk("src/billing/utils.py", start_line=12, end_line=28)]
[calls get_chunk("src/cart/helpers.py", start_line=5, end_line=21)]

Confirmed — identical bodies. I'll consolidate them into src/shared/pricing.py and
remove both originals.

[calls write_fix("src/shared/pricing.py", diff_str="...")]
[calls write_fix("src/billing/utils.py", diff_str="...")]
[calls write_fix("src/cart/helpers.py", diff_str="...")]
[calls git_commit("/home/me/myproject", files=[...], message="refactor: consolidate duplicate calculate_discount")]

Committed: a3f91c2. Running next fix...

Sample scan_repo output

{
  "summary": {
    "total_files": 42,
    "total_functions": 187,
    "total_lines": 8304,
    "languages_detected": ["python"]
  },
  "dead_code": [
    { "symbol": "parse_legacy_csv", "file": "src/importers/csv.py", "line": 44 },
    { "symbol": "_old_validate",    "file": "src/models/user.py",   "line": 112 }
  ],
  "duplicates": [
    {
      "hash": "a3f2...91bc",
      "locations": [
        { "file": "src/billing/utils.py",  "line": 12, "name": "calculate_discount" },
        { "file": "src/cart/helpers.py",   "line":  5, "name": "calculate_discount" },
        { "file": "src/orders/pricing.py", "line": 78, "name": "apply_discount" }
      ]
    }
  ],
  "god_files": [
    { "file": "src/api/handlers.py", "lines": 847, "exports": 23 }
  ],
  "dep_graph": {
    "nodes": ["src/auth/__init__.py", "src/middleware/auth.py"],
    "edges": [{ "from": "src/auth/__init__.py", "to": "src/middleware/auth.py" }],
    "circular": [
      ["src/auth/__init__.py", "src/middleware/auth.py", "src/auth/__init__.py"]
    ]
  },
  "subprojects": [
    { "root": "services/worker", "language": "go",         "test_command": "go test ./..." },
    { "root": "frontend",        "language": "javascript", "test_command": "npm test" }
  ]
}

Sample REFORGE_CHANGES.md

# Reforge Changes

*Generated: 2025-05-02T14:33:00+00:00*

**Health score:** 73.5 (+26.5 from previous scan)

## Fixes Applied

- refactor: consolidate duplicate calculate_discount
- fix: remove dead parse_legacy_csv from src/importers/csv.py
- refactor: split handlers.py into auth_handlers.py and order_handlers.py

## Pending Fixes

- resolve circular dep: src/auth/__init__.py ↔ src/middleware/auth.py
- remove _old_validate from src/models/user.py

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How it works

Reforge works in three phases:

1. Scan

scan_repo walks the repository with parse_directory, feeding each source file to the appropriate tree-sitter adapter (Python, JavaScript/TypeScript, or Go). Tree-sitter builds a full AST — unlike regex, it understands nested scope, decorators, arrow functions, and generics. The adapters extract functions, classes, and imports into typed dataclasses.

From the parse results, three analyses run in sequence:

• Dead code — symbols defined but never referenced anywhere in the repo
• Duplicates — functions whose normalised bodies share the same SHA-256 hash
• God files — files exceeding 500 lines or 10 exported symbols

A dependency graph is built from resolved imports and checked for cycles with DFS. Monorepo subprojects are discovered by scanning subdirectories for marker files (pyproject.toml, package.json, go.mod, tsconfig.json).

2. Plan

Claude Code receives the structured scan report and uses get_chunk to read specific line ranges before deciding what to fix and in what order. The architecture hypothesis, pending fix queue, and health history are all persisted in reforge-state.json via read_memory / write_memory so the plan survives a session restart.

3. Fix

write_fix applies a unified diff atomically:

1. Creates a .bak backup of the target file
2. Best-effort git stash before touching the working tree
3. Parses the diff into hunks and applies them with line-offset tracking
4. Runs the optional test command (validated against the allowlist)
5. On any failure — diff parse error, test exit ≠ 0 — restores from .bak and returns rolled_back: true

git_commit stages only the listed files and creates an atomic commit via GitPython. It reads session_budget and confirm_every from reforge.toml and enforces them: once the session budget is exceeded commits are blocked; at every confirm_every checkpoint the tool returns needs_confirmation: true and waits for confirmed: true before proceeding.

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Security

Boundary	Mechanism
Path traversal	Every file path is validated against repo_root before any read or write — paths that escape the repo root are rejected with SecurityError
Binary / lock files	should_skip_file() blocks binary files, package-lock.json, .yarn.lock, and files over 10 MB before any processing
Test command injection	write_fix validates test_command against an explicit allowlist (pytest, python3 -m pytest, npm test, go test ./..., etc.) before executing
Atomic state writes	reforge-state.json is always written via .tmp → rename — a crash mid-write leaves an orphaned .tmp, not a corrupt file; startup_tasks() cleans these on boot
Pre-fix stash	write_fix attempts git stash before touching the working tree; on rollback the stash is discarded, leaving the repo clean
No network calls	The server makes zero outbound network requests; all analysis is local

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Contributing

# Clone and install
git clone https://github.com/your-org/reforge-mcp.git
cd reforge-mcp
python3 -m venv venv && source venv/bin/activate
pip install -e .
pip install pytest pytest-cov

# Run the full test suite
pytest

# Run with coverage
pytest --cov=src --cov-report=term-missing

Project structure

reforge-mcp/
├── src/reforge_mcp/
│   ├── server.py              # FastMCP server — registers all 7 tools
│   ├── tools/
│   │   ├── scan.py            # scan_repo, get_health_score, monorepo detection
│   │   ├── chunk.py           # get_chunk — line-range file reads
│   │   ├── fix.py             # write_fix — diff apply + rollback
│   │   └── git.py             # git_commit — atomic commits with budget enforcement
│   ├── scanner/
│   │   ├── parser.py          # tree-sitter adapters (Python, JS/TS, Go) + QueryCursor wiring
│   │   ├── dead_code.py       # unused symbol detection
│   │   ├── duplicates.py      # body-hash duplicate detection
│   │   └── adapters/          # per-language project-detection stubs
│   └── utils/
│       ├── state.py           # reforge-state.json load/save, gitignore, changelog
│       ├── security.py        # path validation, file guard, command allowlist
│       └── diff.py            # unified diff parser and applier
├── tests/
│   ├── test_scanner.py
│   ├── test_chunk.py
│   ├── test_fix.py
│   ├── test_git.py
│   ├── test_memory.py
│   └── test_monorepo.py
├── pyproject.toml
└── reforge.toml               # optional per-repo config

reforge.toml reference

[fix]
session_budget = 20      # max commits per Claude session before hard stop
confirm_every  = 5       # pause for confirmation every N commits

[scan]
ignore_dirs = ["generated", "vendor"]

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License

MIT — see LICENSE.