Modular MCP Server

What is Modular MCP Server?

It is a Go implementation of a Model Context Protocol (MCP) server using the mcp-golang library, structured in a modular way. It provides file operations (show, search, write) and shell command execution with security features like path restriction.

How to use Modular MCP Server?

Build and run from source: cd cmd/mcp-server && go build -o mcp-server && ./mcp-server. Configure allowed paths via --paths flag or MCP_ALLOWED_PATHS environment variable, and denied paths via --deny-paths or MCP_DENIED_PATHS. If no paths are specified, the server defaults to the current working directory.

Key features of Modular MCP Server

• File operations: show, search, and write files.
• Execute shell commands with whitelisted utilities.
• Path restriction system to limit file operations.
• Configurable allowed and denied paths via CLI and environment variables.
• Modular tool architecture: easy to add new tools.
• Automatic denial of sensitive directories like .git and .env.

Use cases of Modular MCP Server

• Allowing an AI assistant to read and write files within a safe directory.
• Executing predefined shell commands in a restricted environment.
• Providing a secure file editing interface for MCP clients.
• Extending with custom tools for domain-specific operations.

FAQ from Modular MCP Server

What dependencies are required?

Requires Go to build; uses github.com/metoro-io/mcp-golang library. No other external runtime dependencies are mentioned.

How do I configure allowed paths?

Use the --paths flag (colon‑separated) or MCP_ALLOWED_PATHS environment variable. Denied paths can be set with --deny-paths or MCP_DENIED_PATHS.

What is the default behavior if no paths are configured?

If no paths are specified, the server defaults to allowing only the current working directory.

What security measures are in place for shell commands?

Commands are restricted to a whitelist of common utilities; custom executable paths are checked against allowed paths; working directories must be within allowed paths.

How can I add a new tool?

Create a new file in internal/tools, implement the Tool interface (and optionally ConfigAware for configuration access), then register the tool in cmd/mcp-server/main.go.