What is Serena MCP, and how does it work with a memory server?

Last updated October 31, 2026

Serena is an open-source MCP server that gives coding agents IDE-like tools: it finds, reads and edits code by symbol (functions, classes, references) through language servers, with support for over 40 programming languages. You add it to Claude Code, Codex and other MCP clients so the agent navigates code by meaning instead of grepping and reading whole files. Serena also keeps "memories," Markdown notes about a project stored in .serena/memories/. It's a code tool first, not a memory service, and it pairs well with a memory server that holds decisions shared across agents and people.

What Serena does

Serena's repository calls it "a powerful MCP toolkit for coding, providing semantic retrieval and editing capabilities - the IDE for your agent." Its tools work "at the symbol level," using "language servers implementing the language server protocol (LSP)," with "support for over 40 programming languages." It can also use a JetBrains plugin instead of language servers.

Some of its tools, from Serena's tool list:

• find_symbol: "Performs a global (or local) search using the language server backend."
• find_referencing_symbols: "Finds symbols that reference the given symbol."
• replace_symbol_body: "Replaces the full definition of a symbol."
• rename_symbol: renames a symbol throughout the codebase using the language server's refactoring.
• onboarding: identifies "the project structure and essential tasks, e.g. for testing or building."

On October 31, 2026 the repository had about 31,000 GitHub stars. The Serena application is under GPL-3.0-or-later, and its language-server layer (SolidLSP) under MIT.

Add Serena to Claude Code

Serena's README warns: "Do not install Serena via an MCP or plugin marketplace!" because those carry outdated commands. Serena is managed with uv. Its documented install is:

uv tool install -p 3.13 serena-agent

Then, from Serena's client guide, add it to Claude Code for all your projects:

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

Serena lists Claude Code, Codex, OpenCode, Gemini CLI, Claude Desktop, VS Code, JetBrains IDEs and others as clients; its client guide has the steps for each. Serena runs on your computer, started by the client, so there's no account or sign-in.

Serena's memories

Serena has "project-specific memories, which are stored in the .serena/memories/ directory within your project folder, and global memories" in ~/.serena/memories/global/. Project memories can be committed with your code. The agent manages them with tools such as write_memory ("Write some information… about this project that can be useful for future tasks to a memory in md format"), read_memory, list_memories, edit_memory and delete_memory. The first time Serena meets a project with no memories, it runs onboarding to learn the project and saves what it finds.

Serena memories vs a memory server

They don't compete. Serena makes the agent better at reading and changing code. A memory server keeps the knowledge that isn't in the code, such as why a choice was made, and makes it available to agents outside this checkout, including chat apps.

Use them together

1. Add Serena for code navigation and editing.
2. Add a memory server for shared knowledge. For Memlo in Claude Code: claude mcp add --transport http --scope user memlo https://memlo.ai/mcp, then /mcp to sign in. See Claude Code memory between sessions.
3. In CLAUDE.md or AGENTS.md, say which is which: "Use Serena's tools to find and edit code. Search memlo for decisions before you change code, and save new decisions there."

Frequently asked questions

What is Serena MCP?

An open-source MCP server from Oraios that gives coding agents symbol-level tools to find, read and edit code through language servers, for over 40 languages.

How do I install Serena MCP?

Serena's README says to install it with uv (uv tool install -p 3.13 serena-agent) and not through MCP marketplaces, then add it to your client. For Claude Code, its client guide gives claude mcp add --scope user serena -- serena start-mcp-server --context claude-code --project-from-cwd.

Is Serena a memory server?

Not mainly. It's a code-navigation and editing toolkit that also keeps project memories as Markdown files in .serena/memories/.

Is Serena free?

Yes, it's open source: the application under GPL-3.0-or-later and its language-server layer under MIT. It runs on your computer.

Can Serena and Memlo run together?

Yes. They're separate MCP servers with different tools: add both to your agent and tell it which to use for what.

Sources

Checked on October 31, 2026:

• Serena on GitHub
• Serena tools, memories and clients, Serena documentation
• Memlo: the setup page