code-mode-mcp-server

MCP server that exposes code-mode sandbox execution as tools for any MCP-compatible client.

LLMs write TypeScript code that chains tool calls in an isolated sandbox — achieving 96% token savings vs sequential tool calling.

Quickstart

# Install globally
npm install -g code-mode-mcp-server

# Create a config file with your tool sources
cat > tools.json << 'EOF'
{
  "toolSources": [
    {
      "name": "fs",
      "call_template_type": "mcp",
      "config": {
        "mcpServers": {
          "filesystem": {
            "transport": "stdio",
            "command": "node",
            "args": ["/path/to/server-filesystem/dist/index.js", "/allowed/dir"]
          }
        }
      }
    }
  ],
  "timeout": 30000,
  "memoryLimit": 128
}
EOF

# Run the server
code-mode-mcp-server --config ./tools.json

MCP Tools

| Tool | Description | |------|-------------| | execute_code_chain | Execute TypeScript code in the sandbox with pre-configured tools | | list_available_tools | List available sandbox tools with TypeScript interfaces |

The execute_code_chain tool description dynamically includes TypeScript interfaces for all registered tools, so the LLM knows what's available.

CLI Options

--config <path>      Path to config JSON file (required)
--timeout <ms>       Override execution timeout (default: 30000)
--memory-limit <mb>  Override sandbox memory limit (default: 128)
--trace              Enable execution tracing

Config Format

{
  "toolSources": [
    {
      "name": "source-name",
      "call_template_type": "mcp",
      "config": {
        "mcpServers": {
          "server-name": {
            "transport": "stdio",
            "command": "node",
            "args": ["path/to/server.js", "arg1"]
          }
        }
      }
    }
  ],
  "timeout": 30000,
  "memoryLimit": 128,
  "enableTrace": false
}

Client Configuration

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "code-mode": {
      "command": "code-mode-mcp-server",
      "args": ["--config", "/path/to/tools.json"]
    }
  }
}

Claude Code

Add to .mcp.json in your project root:

{
  "mcpServers": {
    "code-mode": {
      "command": "code-mode-mcp-server",
      "args": ["--config", "./tools.json"]
    }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "code-mode": {
      "command": "code-mode-mcp-server",
      "args": ["--config", "./tools.json"]
    }
  }
}

Requirements

• Node.js >= 22 (required by isolated-vm)
• Build toolchain for native modules (node-gyp)

Architecture

MCP Client → stdio → code-mode-mcp-server
                        ├── McpServer (2 tools)
                        ├── CodeModeEngine (persisted)
                        │   └── Tool sources (MCP servers, HTTP APIs)
                        └── isolated-vm sandbox

License

MPL-2.0