Serena

Serena gives Claude the code-navigation tools a developer gets from a proper IDE. It uses language servers, the same engines behind "go to definition" in your editor, so Claude can jump straight to a function, find every place it's used and edit it by name instead of reading whole files line by line.

That pays off in large projects. Claude reads less, spends fewer tokens and makes fewer broken edits. It supports 40+ languages, though some need their language server installed separately.

Install it with uv, then run serena setup claude-code. The Serena team warns against MCP marketplace listings, which carry outdated commands. Their docs also suggest a small hook that reminds Claude to use Serena's tools, because Claude Code sometimes forgets they're there.

• Jump to where a function is defined and see everything that uses it
• Get an outline of a file without reading every line
• Replace a whole function or class by name, not by line number
• Rename something safely across the entire codebase
• See compiler and linter errors for a file
• Keep project notes that carry over between sessions

Open your terminal in the project folder and run:

claude mcp add --scope user serena -- serena start-mcp-server --context claude-code --project-from-cwd

Other ways to set it up:

# Install Serena first (needs uv):
uv tool install -p 3.13 serena-agent
serena init
# Or let Serena register itself with Claude Code:
serena setup claude-code

Developers using Claude Code on large or unfamiliar codebases.

• Large codebases
• Safe refactors and renames
• Understanding unfamiliar code
• Cutting token use