I just released a plugin for my LLM command-line tool that adds support for the new Claude 3 models:
pipx install llm
llm install llm-claude-3
llm keys set claude
# paste Anthropic API key here
llm -m claude-3-opus '3 fun facts about pelicans'
llm -m claude-3-opus '3 surprising facts about walruses'
More on LLM: https://llm.datasette.io/