ScarTissue MCP

ScarTissue is a PR review agent that warns when a pull request appears to reintroduce a historical bug pattern from the same repository. It mines prior bug-fix commits, stores them as searchable "scar tissue," and exposes the review workflow as an MCP stdio server for Claude Code, Codex CLI, Gemini CLI, and other MCP clients.

Install

pip install scartissue-mcp

After installation, start the MCP stdio server with:

scartissue-mcp

Configuration

Set these environment variables in your MCP client config:

Claude Code

Add this to ~/.claude/mcp.json or workspace .claude/mcp.json:

{
  "mcpServers": {
    "scartissue": {
      "command": "scartissue-mcp",
      "env": {
        "ANTHROPIC_API_KEY": "sk-ant-...",
        "NIA_API_KEY": "nia_...",
        "GITHUB_TOKEN": "ghp_...",
        "CHROMA_PERSIST_DIR": "/absolute/path/to/scartissue/chroma_db"
      }
    }
  }
}

Codex CLI

Add this to ~/.codex/mcp_servers.toml:

[scartissue]
command = "scartissue-mcp"

[scartissue.env]
ANTHROPIC_API_KEY = "sk-ant-..."
NIA_API_KEY = "nia_..."
GITHUB_TOKEN = "ghp_..."
CHROMA_PERSIST_DIR = "/absolute/path/to/scartissue/chroma_db"

Gemini CLI

Add this to ~/.gemini/settings.json under mcpServers:

{
  "mcpServers": {
    "scartissue": {
      "command": "scartissue-mcp",
      "args": [],
      "env": {
        "ANTHROPIC_API_KEY": "sk-ant-...",
        "NIA_API_KEY": "nia_...",
        "GITHUB_TOKEN": "ghp_...",
        "CHROMA_PERSIST_DIR": "/absolute/path/to/scartissue/chroma_db"
      }
    }
  }
}

Tools

• scartissue_index_repo: mine a repository's git history and index historical bug-fix incidents.
• scartissue_review_pr: review a GitHub pull request against previously indexed scar tissue.
• scartissue_search_scar_tissue: search indexed incident history for bug-fix examples related to a query.
• scartissue_list_indexed_repos: list indexed repositories with incident counts and last-indexed timestamps.

Index a repository once with scartissue_index_repo before reviewing PRs from that repository.

Links

• Web UI: https://scartissue.dev
• GitHub: https://github.com/ShivamSinghNow/scartissue