Out of the box, a coding agent finds code with text search and edits it by replacing lines. Serena, an open-source project by Oraios AI, gives it the tools an IDE has: find a symbol, find everything that references it, rename it everywhere, replace a function body.
It runs real language servers, so it understands 40+ languages, from TypeScript and Python to Go, Rust and Java. A paid JetBrains plugin is an alternative backend that adds moves, inlining and debugging. On a large codebase, the agent follows references instead of grepping and reading whole files.
A real run
We pointed it at the editor package that renders our articles and asked what it takes to add a new MDX component. Serena followed the references instead of grepping, found the three callers and named the one object to change. It also caught a side effect: the new component would vanish when the editor converts blocks back to markdown.
Watch out
- It pays off on large codebases. On a small repo, it's extra startup time for what grep already does.
- Some languages need their own language server installed. Check the language support page.
Install
Serena needs uv. Then:
Terminal
Loading editor...
uv tool install -p 3.13 serena-agent && serena setup claude-code
For Codex, Cursor, Claude Desktop and other clients, see the client setup guide. Serena asks you not to install it from MCP marketplaces, which carry outdated commands.
More in Top MCP servers for development.
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