Command line (CLI)

Invoke the one binary as modelcontextprotocol. Select exactly one server in either equivalent form; there is no configuration-file option.

modelcontextprotocol filesystem [DIR ...]
modelcontextprotocol fetch [--respect-robots-txt] [--user-agent <UA>] [--proxy-url <URL>]
modelcontextprotocol memory [--memory-file <PATH>]
modelcontextprotocol shell [DIR ...]
modelcontextprotocol skills [DIR]
modelcontextprotocol agents [DIR]

modelcontextprotocol --filesystem [DIR ...]
modelcontextprotocol --fetch [--respect-robots-txt] [--user-agent <UA>] [--proxy-url <URL>]
modelcontextprotocol --memory [--memory-file <PATH>]
modelcontextprotocol --shell [DIR ...]
modelcontextprotocol --skills [DIR]
modelcontextprotocol --agents [DIR]

skills and agents each accept one workspace directory. filesystem and shell accept one or more allowed directories. All four default to the MCP server process's current directory when no directory is supplied.

Server	Identity	Server-specific options
filesystem	mcp-filesystem	none
fetch	mcp-fetch	--respect-robots-txt, --user-agent <UA>, --proxy-url <URL>
memory	mcp-memory	--memory-file <PATH>
shell	mcp-shell	none
skills	mcp-skills	none
agents	mcp-agents	none

Selection and validation

Selection is strict: exactly one subcommand or top-level selector must be present. Any mixed selectors or option belonging to another server prints usage to stderr and exits 1. For example, fetch --memory, skills /workspace --user-agent UA, and agents /workspace --memory-file memory.jsonl are rejected. The two workspace servers have no options beyond their one positional workspace.

Filesystem and shell roots are expanded, made absolute, and canonicalized; unusable roots are warned about and startup fails when none remain. Skills and agents canonicalize their workspace and require it to be a directory. An omitted directory is treated as . before this validation.

Environment variables

Variable	Used by	Description
RUST_LOG	all servers	tracing filter; defaults to modelcontextprotocol=warn. Logs use stderr only.
MEMORY_FILE_PATH	memory	JSONL path, overridden by --memory-file; default memory.jsonl in the current directory.
OPENAI_API_KEY	agents default OpenAI definitions	Default env_key for model_provider: openai.
ANTHROPIC_API_KEY	agents default Anthropic definitions	Default env_key for model_provider: anthropic.
a definition's env_key	agents	Credential for that definition; custom definitions can use different names, such as OPENROUTER_API_KEY.
OPENROUTER_API_KEY, OPENROUTER_MODEL	legacy OpenRouter E2E only	Not read by the six MCP servers unless an agent definition explicitly uses OPENROUTER_API_KEY as its env_key.

--help/-h prints clap help; --version/-V prints the crate version. After startup, the selected server serves stdio JSON-RPC until the transport closes.