CodeGraph Auto MCP

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Give GitHub Copilot deep structural understanding of your codebase — not just text search, but AST-level code intelligence via CodeGraph MCP.

This extension auto-registers the CodeGraph MCP server for Copilot. No manual mcp.json editing, no path headaches, no config files to maintain.

⚡ Quick Start

# 1. Install CodeGraph CLI
npm install -g @sven/codegraph

# 2. Install this extension (VSIX from Releases, or build from source)
# 3. Open any project → Ctrl+Shift+P → "CodeGraph: Initialize Project"
# 4. Done! Copilot now understands your codebase structurally.

Once initialized, Copilot gains tools like codegraph_explore that let it navigate call graphs, trace data flow, and understand cross-file dependencies — far beyond what text-based context can provide.

Why Use This?

Without CodeGraph MCP, Copilot sees your code as text. It can grep for symbols, read files you point it to, and guess at relationships.

With CodeGraph MCP, Copilot gets a pre-built knowledge graph of your entire codebase:

• Call graphs — who calls this function, and what calls them?
• Data flow — where does this value come from, and where does it end up?
• Cross-file understanding — dependencies, re-exports, type propagation across modules
• Blast radius analysis — what breaks if I change this symbol?

The result: more accurate answers, fewer hallucinated APIs, and edits that actually respect your codebase's architecture.

Features

• 🚀 Zero-config — installs and works. Automatically finds the CLI, detects workspace paths, registers MCP with Copilot
• 🔄 Self-healing — smart retry (2s/5s/10s) handles shell environment race conditions on startup
• 👁️ Auto-detect init — file watcher picks up when you run codegraph init or codegraph sync, no restart needed
• 🛠️ Command palette — Initialize Project and Force Re-index right from VS Code
• 👆 Status bar — always shows current state; click to retry or access commands
• 🌐 Cross-platform — macOS, Linux, Windows (auto-detects codegraph.cmd)
• 📦 Lightweight — zero runtime dependencies, ~20KB bundled

Commands

Access via Cmd+Shift+P / Ctrl+Shift+P.

How It Works

The extension runs a simple state machine on startup:

1. Find CLI — searches PATH, shell environment, nvm/fnm/volta/asdf dirs, and common install locations
2. Check init — runs codegraph status to see if .codegraph/ exists and is valid
3. Warm up daemon — pre-spawns the codegraph daemon to avoid cold-start latency on first Copilot call
4. Register MCP — calls vscode.lm.registerMcpServerDefinitionProvider to expose tools to Copilot

If any step fails, the status bar shows the issue. A file watcher on .codegraph/ auto-recovers when you run codegraph init or codegraph sync in a terminal.

Installation

Prerequisites

• VS Code ^1.106.0 with GitHub Copilot
• CodeGraph CLI: npm install -g @sven/codegraph

Install the Extension

From Releases:

1. Download the latest .vsix
2. VS Code → Extensions: Install from VSIX... → select the file

From source:

git clone https://github.com/svenzhao/codegraph-auto-mcp.git
cd codegraph-auto-mcp
npm install && npm run build
code --install-extension codegraph-auto-mcp-*.vsix

For Developers

Architecture

Uses the official VS Code API vscode.lm.registerMcpServerDefinitionProvider — the same pattern as GitLens for its MCP server:

vscode.lm.registerMcpServerDefinitionProvider("codegraph", {
  provideMcpServerDefinitions(_token) {
    return [
      new vscode.McpStdioServerDefinition(
        "CodeGraph",
        codegraphPath,
        ["serve", "--mcp", "--path", workspaceRoot],
      ),
    ];
  },
});

CLI discovery uses a 7-layer fallback: user config → cached path → PATH → npm prefix → node version managers (nvm/fnm/volta/asdf/n) → common dirs → shell command -v.

Building

npm run build      # typecheck + esbuild bundle
npm run watch      # dev mode with file watcher
npm run release    # bump version + tag (standard-version)
npm run publish    # release + publish to Marketplace

License

MIT