When to Use MCP vs CLI

It's not a religion. It's a decision framework.

✅ Use a CLI when...

  • Stateless: query in, data out
    osgwiki-cli, lvt, git, az kusto
  • Local tool on your machine
    build tools, debuggers, file analysis
  • You want it to work with any agent
    Claude Code, Copilot, Codex, Cursor...
  • Speed matters (no startup overhead)

✅ Use MCP when...

  • Remote service behind enterprise auth
    ICM, ADO via Agency proxy
  • Auth is the hard part (EntraID, SSO)
    agency mcp remote --url ...
  • The service already has an MCP server
    Slack, Sentry, hosted databases
  • Containerized/shared team deployment
The heuristic: Can the agent just run a command and read stdout?
If yes → CLI. If the blocker is auth or remote access → MCP.
“Even if you make a GUI app, add a cli so agents can test the core logic directly — much faster iteration cycles.”
— Peter Steinberger (@steipete), Dec 25, 2025 · https://x.com/steipete/status/2004303530887405889
Tweet screenshot: add a CLI even for GUI apps