Anthropic's Claude has become the go-to model for developers who need a thinking partner rather than autocomplete. It handles large inputs well, so a whole module, an API surface or a long stack trace can go in at once, and it is unusually good at catching logic flaws and edge cases rather than just syntax errors.
Strongest at: reasoning through code. Debugging, architectural review, writing tests, documenting legacy systems and explaining unfamiliar code are where it consistently earns its place. Claude Code, Anthropic's agentic tool, extends that to working across a repository from the terminal - reading files, running tests and making changes.
Worth knowing: agentic changes can touch more than you expect. Review diffs as carefully as you would a colleague's pull request, and keep the agent's permissions scoped to what the task needs.
Best for: code review, hard debugging, test writing, documentation and understanding unfamiliar codebases. The model is available in Chat Smith as Claude Sonnet 5 for questions you want to reason through in chat.