CircleCI has released a ground-up rewrite of its CLI in Go, now in beta. The new CLI is designed with a human-first philosophy while being fully agent-compatible. Key features include: universal --json and built-in --jq flags on every data-returning command, browser-based OAuth login with system keyring storage, an interactive TUI built on bubbletea for debugging runs without a browser, structured error messages with stable exit codes, and a built-in MCP server that integrates with Claude Desktop, Cursor, and VS Code in one command. Design principles were codified before any code was written, covering output formatting, error structure, flag naming, and telemetry (opt-out, auto-disabled in CI). The rewrite was motivated partly by the need to support coding agents, which require consistent JSON output and stable exit codes that the old CLI couldn't reliably provide.
