A CLI speaks text. People copy it; scripts pipe it. MCP wraps a similar capability as a typed tool: parameters, results and errors are meant for a model.
If you already have a stable CLI and the job is one command, skip another MCP layer. An agent can run git, rg or a repo script. MCP fits sessions, permission fences, or repeated access to the same system.
Filesystem, browser and database are the usual grey area. Searching a few files is CLI work. Limiting writable directories, keeping a login, or re-reading a schema is MCP work.
Pick one directory entry here that already has install metadata and compare it with the CLI you already use. If one command is enough, do not wire a server yet.