CLI Entrypoint

Relevant source files

The following files were used as context for generating this wiki page:

• mbbank_mcp/__main__.py
• mbbank_mcp/core.py
• pyproject.toml
• README.md
• mbbank_mcp/modals.py
• mbbank_mcp/__init__.py

The CLI Entrypoint is the primary interface for initializing and running the MBBank Model Context Protocol (MCP) server. It manages credential retrieval, authentication with the MBBank API, and the selection of server communication protocols (Stdio or SSE).

The entrypoint is defined in mbbank_mcp/__main__.py and exposed as a console script named mbbank-mcp via the project configuration. It acts as the bridge between the user's shell environment and the core logic found in mbbank_mcp/core.py.

Command Line Configuration

The CLI is built using the click library, providing a structured set of options for configuring the server at runtime. Users can provide credentials either through command-line flags or environment variables.

Configuration Options

Option	Environment Variable	Default	Description
--username	MBBANK_USERNAME	None	The account username for MBBank authentication.
--password	MBBANK_PASSWORD	None	The account password for MBBank authentication.
--host	N/A	localhost	The host address for the SSE server.
--port	N/A	3000	The port for the SSE server.
--sse	N/A	False	Flag to enable Server-Sent Events and HTTP mode instead of Stdio.

Sources: mbbank_mcp/__main__.py:20-33, README.md:65-71, pyproject.toml:31

Execution Flow

When the CLI is invoked, it performs a sequence of initialization steps: credential validation, client instantiation, authentication verification, and finally, starting the server in the requested mode.

The application uses asyncio.run to trigger the initial authentication before determining which server transport to utilize.
Sources: mbbank_mcp/__main__.py:34-45, mbbank_mcp/__main__.py:73-77

Server Transport Modes

The entrypoint supports two distinct communication modes for the MCP server:

Stdio Mode

This is the default mode. The server communicates via standard input and output (stdin/stdout). This is typically used when the MCP server is managed as a subprocess by an MCP client, such as Claude Desktop.
Sources: mbbank_mcp/__main__.py:74-77, README.md:21-36

SSE (Server-Sent Events) Mode

Enabled with the --sse flag, this mode wraps the MCP server in a Starlette application and serves it via Uvicorn. It provides two endpoints:

• /sse: The Server-Sent Events endpoint.
• /mcp: The streamable HTTP endpoint.

Internal Components

The CLI entrypoint coordinates several key components:

• MBBankAsync: The underlying client from mbbank-lib that handles API calls to the bank.
• crate_mcp_server: A factory function from mbbank_mcp/core.py that configures the FastMCP instance with available tools like get_balances and start_transfer.
• eprint: A utility function to ensure error messages are written to sys.stderr, preventing interference with the MCP protocol messages on stdout when in Stdio mode.

Sources: mbbank_mcp/__main__.py:13-18, mbbank_mcp/core.py:23-28, mbbank_mcp/modals.py:7-12

Summary

The CLI Entrypoint provides a flexible way to launch the MBBank MCP server. By handling both environment variables and direct CLI arguments, it accommodates various deployment scenarios ranging from local development (SSE mode) to integration with AI assistants (Stdio mode via Docker or uvx).