gen-system's Understand engine as an MCP server. It gives an AI agent parser facts about a codebase: the architecture, symbols, call graphs, control flow graphs, effects, source and the beliefs gen-system holds about each routine. No model writes these answers; deterministic parsers for Go, COBOL with copybooks, CA Gen, Java, TypeScript and Python do.

The server is read only. It runs locally and sends nothing anywhere.

Use it

Claude Code

claude mcp add gen-understand -- npx -y gen-understand --root /path/to/your-repo

Codex (~/.codex/config.toml)

[mcp_servers.gen-understand]
command = "npx"
args = ["-y", "gen-understand", "--root", "/path/to/your-repo"]

Cursor (.cursor/mcp.json)

{
  "mcpServers": {
    "gen-understand": {
      "command": "npx",
      "args": ["-y", "gen-understand", "--root", "."]
    }
  }
}

Tools

architecture, search_symbols, call_graph, control_flow, source, file_symbols, effects and beliefs. With --allow-corrections, also correct_belief. The full list, the flags and the protocol details are in docs/mcp.md.

How this package works

The server is a Go binary. On first run this package downloads the binary for your platform from the gen-system release of the same version, checks its SHA-256 against the release's checksums.txt, and caches it. Later runs start at once and work offline. Builds exist for Linux, macOS and Windows, on x64 and arm64.

Variable	Use
`UNDERSTAND_MCP_BINARY`	Path of a local `understand-mcp` binary. Skips the download, for offline machines
`UNDERSTAND_MCP_CACHE`	Folder for the downloaded binary. Default: the user cache folder

Without npm, install the binary with Go: go install github.com/hpdkhoa/gen-system/generator/cmd/understand-mcp@latest.