Plan Mode vs Extended Thinking in Claude Code

📖 See also: Glossary: Claude Code Building Blocks for a full breakdown of all the pieces (skills, hooks, subagents, MCP, plugins, etc.)

Plan Mode and Extended Thinking are independent features in Claude Code — something I didn't realize until I actually read the docs.

Plan mode

Plan Mode restricts what Claude does. It's read-only: Claude explores your codebase, builds a plan, and waits for your approval before touching anything. Useful when you want to review direction before any edits happen. Toggle with Shift+Tab.

Thinking

Extended Thinking changes how Claude reasons. It works through the problem step-by-step with extra thinking tokens before responding — visible as gray italic text when verbose mode is on. Doesn't restrict actions, just deepens the internal process. Toggle with Option+T. It costs more.

The interesting part: you can combine them. Plan Mode for safe exploration, Extended Thinking for deeper analysis of complex architecture. Two different dimensions of control over the same tool.