Git Security

Git MCP is an MCP server that helps LLM agents analyze GitHub repositories for security risk and codebase shape.

It combines four practical scans:

• Secrets exposure in commit history
• Dependency inventory from common manifest files
• Dependency CVE scan using Trivy
• Hotspot detection (frequently changed files)

It also includes a repository summarizer that returns relevant file paths and contents for downstream reasoning.

Objectives

This project demonstrates building an MCP-native security workflow that is:

• Tool-driven (LLM invokes structured capabilities, not ad-hoc scripts)
• Operationally aware (timeouts, error categorization, and binary checks)
• Agent-friendly (standardized response envelope for reliable parsing)

Tech stack

• Python 3.11+
• FastMCP (mcp.server.fastmcp.FastMCP)
• Pydantic response models
• External scanners:
  • TruffleHog (via Docker image)
  • Trivy (local binary)

Repository layout

src/git_mcp/
	server.py                # MCP server and tool registration
	models/responses.py      # Standard ToolResponse schema
	tools/
		secrets.py             # GitHub secret scan (TruffleHog via Docker)
		dependencies.py        # Dependency extraction + Trivy CVE scan
		hotspots.py            # Git churn hotspot scan
		clone.py               # Repo clone helper + repository summarizer
		prerequisites.py       # Local runtime binary checks

Prerequisites

Install the following on your machine and ensure they are on PATH:

• uv
• git
• docker (required for secret scanning)
• trivy (required for CVE scanning)

Installation

uv sync

Run the MCP server

uv run git-mcp

This starts the MCP server over stdio, suitable for MCP-compatible clients/agents.

MCP tools

run_github_secret_scan(owner, repo, scan_depth=50)

Scans GitHub commit history for exposed secrets using containerized TruffleHog.

run_dependency_scan(owner, repo)

Extracts dependencies from root-level package.json, pyproject.toml, and requirements.txt.

run_github_dependency_cve_scan(owner, repo, severity_threshold="HIGH")

Runs Trivy vulnerability scan on extracted dependencies and returns CVE findings at or above the threshold.

run_github_hotspot_scan(owner, repo, scan_depth=50)

Finds high-churn files from Git history (git log --name-only) to identify risk hotspots.

run_summarize_repository(owner, repo)

Clones the repository and returns relevant source/text files (excluding .git, node_modules, __pycache__) with lightweight summary metadata.

Response contract

All tools return a shared ToolResponse schema with:

• status: ok | degraded | error
• summary: concise human-readable outcome
• findings: structured list payload
• optional error_category and error_detail

This consistency improves reliability when wiring multiple tools into one agent loop.

Notes and current limitations

• Dependency extraction currently checks only top-level repository manifests.
• Secret scanning relies on Docker availability at runtime.
• CVE scanning requires local Trivy installation.
• Default command timeouts are tuned for interactive agent usage and may need adjustment for large repositories.