What it is: Claude Code runs only Anthropic models: every alias — default, best, fable, sonnet, opus, haiku and opusplan — resolves to a Claude model, and changing the base URL moves where the request goes without changing which model answers it. [code.claude.com/docs/en]
Choose Claude Code when: Plan a change with Opus and execute it with Sonnet inside one session, by setting the model to `opusplan`. [code.claude.com/docs/en]
Where it hurts: You cannot audit, fork or patch the agent: the repository publishes the changelog, plugins and examples, not the CLI source, under an all-rights-reserved licence. GitHub Copilot CLI is the only other tool in this set that does the same. [github.com/anthropics/claude-code]
Price: Claude Pro costs $17 per month on the annual plan, $200 billed up front, or $20 per month billed monthly; Max starts at $100 per month. [claude.com/pricing]