Serena

What it does

Serena gives an agent semantic tools for code: find a symbol, find its references, and edit or refactor at the symbol level. It works on the structure of the code, much like an IDE, instead of text search over whole files.

Why it is useful

• The agent reads only the code it needs, which saves tokens on large codebases.
• Edits are more precise, because they target symbols, not line numbers.

How to use it

Add Serena as an MCP server in your client (the README has a command for each tool), then point it at your project.

Watch out for

• It is most useful on medium and large codebases. On small projects the setup may not pay off.
• Language support depends on the language servers it can run.