Overview
Serena is an MCP server that gives coding agents the tools an IDE gives a developer. Instead of reading files line by line or searching for text, an agent can ask for a symbol, its references or a file outline, and make edits at the symbol level. It works with any MCP client, including Claude Code, Codex, Gemini CLI, Cursor, VS Code and JetBrains assistants. Serena v2 adds a REPL-based agent interface.
Key capabilities
- Symbol retrieval: find symbols, file outlines and referencing symbols without reading whole files.
- Refactoring: cross-file renames and moves as single tool calls rather than many text edits.
- Diagnostics: surface language-server or IDE inspections to the agent.
- Memory: a memory system for long-running agent workflows.
- Two backends: free language servers (40+ languages) or the paid JetBrains plugin.
Tradeoffs
- Gains are largest on big, multi-file codebases; on small scripts the agent's built-in tools are often enough.
- Some features, such as type hierarchy and dependency search, need the paid JetBrains backend.
- You still need an LLM client to drive it; Serena supplies tools, not a model.
Ideal for
- Large or multi-language codebases
- Teams using Claude Code, Codex or Copilot CLI for refactors
- Developers who want IDE-grade navigation for their agent
Not ideal for
- Small one-file projects
- Non-code work
Getting started
- Pick a client that supports MCP, such as Claude Code, Codex, Gemini CLI, Cursor or Claude Desktop.
- Give the client Serena's launch command, or start the Serena MCP server in HTTP mode and give the client its URL. The Quick Start in the README has the exact commands per client.
- Open a project and ask the agent to use Serena's tools for navigation and refactors, for example renaming a function across files.
- If you use a JetBrains IDE and want type hierarchy and dependency search, try the paid JetBrains plugin backend (free trial).
Technical notes
- Protocol: MCP (launch command or HTTP mode)
- Backends: LSP language servers (default) or Serena JetBrains Plugin (paid)
- Docs: oraios.github.io/serena
- Source: oraios/serena
- GitHub stars: 31,315 (as of 2026-11-12)