Comment by simonw

Claude Code doesn't do anything with semantic search or embeddings out of the box. They use a simple grep tool instead.

Neither does OpenAI's Codex CLI - you can confirm that by looking at the source code https://github.com/openai/codex

Cursor and Windsurf both use semantic search via embeddings.

You can get semantic search in Claude Code using this unofficial plugin: https://github.com/zilliztech/claude-context - it's built by and uses a managed vector database called Zilliz Cloud.