LABSCO SUMMARY

Pick the backend before you install: the free one does less.

Language servers are open-source and cover retrieval, renaming symbols, and symbolic editing. Move, inline, dead-code propagation, type hierarchy, dependency search and the interactive debugger only exist on the paid JetBrains plugin, and the README publishes that split as a table rather than burying it. The reason to bother either way is that a cross-file rename becomes one atomic call instead of a sequence of careful text edits.

What it is

A semantic code toolkit for coding agents, powered either by language servers speaking LSP (the free default) or by the paid Serena JetBrains plugin. Instead of line numbers and regex, its tools operate on symbols and the relationships between them, which is why it holds up in large codebases.

What you get

Symbol-level retrieval on both backends: find symbol, file outline, find referencing symbols, find declaration, find implementations, query external projects, and diagnostics
Symbolic editing that avoids rewriting whole files: replace a symbol's body, insert before or after a symbol, and safe delete
Renaming of symbols on the language-server backend; the JetBrains backend adds renaming files and directories, move, inline, and propagating deletions to remove unused code
Search in project dependencies and type hierarchy — JetBrains backend only
Interactive debugging, exclusive to the JetBrains plugin: set breakpoints, inspect variables, evaluate expressions and control execution through a persistent REPL-style interface
Basic utilities for completeness, usually disabled inside harnesses that already have them — search_for_pattern, replace_content, list_dir, find_file, read_file, execute_shell_command
A memory system for knowledge that outlives a session, which can be turned off if you prefer your agent's own

Requirements

uv is the only hard prerequisite. Install with uv tool install -p 3.13 serena-agent, then run serena init to set up and verify — it configures the language-server backend by default, or -b JetBrains for the plugin. Connect it either by giving your client a launch command or by starting the server in HTTP mode and handing over the URL. The published package is serena-agent, run over stdio via uvx, with a --context matching your client. Some languages need extra dependencies installed for their language server. Do not install it from a plugin marketplace — the README says those carry outdated commands.

Setup effort

Follow the published steps — uv tool install -p 3.13 serena-agent

See installation options

USE CASES

Changing a function that is called all over a large codebase

Find the symbol, list what references it, then rename — one operation with the compiler's understanding behind it rather than search-and-replace across files.

find_symbolfind_referencing_symbolsrename_symbol

Editing one method without re-emitting the file

Replace that symbol's body directly, or insert a new symbol before or after it. Token cost tracks the symbol, not the file.

replace_symbol_body

Understanding unfamiliar code before touching it

Read the file outline for structure, jump to declarations and implementations, and follow the reference graph — the way you would with an IDE open.

get_symbols_overviewfind_symbolsearch_for_pattern

Restructuring a package

Move symbols, files and directories, inline what should not exist, and propagate deletions to clear the code left unused. This path needs the JetBrains backend.

rename_symbolfind_referencing_symbolslist_dirfind_file

16 tools

Listed in project docs. Your client may show a different list.

find_symbol

find_referencing_symbols

get_symbols_overview

replace_symbol_body

rename_symbol

search_for_pattern

replace_content

list_dir

find_file

read_file

execute_shell_command

activate_project

read_memory

write_memory

list_memories

INSTALLATION

Connect your client

Server setup

Install uv (https://docs.astral.sh/uv/getting-started/installation/) — Serena is managed by uv, and installing uv is the only required prerequisite

With uv installed and on your PATH, install Serena with this command

TERMINAL

uv tool install -p 3.13 serena-agent

Upon completion, the command serena should be available in your terminal. To test the installation and initialise Serena, run one of the following commands — for the default language intelligence backend (language servers)

TERMINAL

serena init

or, if you intend to use the JetBrains backend (which uses the JetBrains plugin)

TERMINAL

serena init -b JetBrains

Then add Serena to your client — pick it under MCP Clients. Verify the connection (e.g. /mcp in Claude Code or Codex); if Serena is slow to start, raise MCP_TIMEOUT

Strongly recommended for Claude Code / VSCode / Copilot CLI: install the serena-hooks reminder hooks (remind / activate / cleanup / auto-approve) — an alpha feature that counteracts agent drift and dynamic tool loading

To update later:

TERMINAL

uv tool upgrade serena-agent

To uninstall:

TERMINAL

uv tool uninstall serena-agent

MCP Clients

Claude Code

CLAUDE CODE · TERMINAL

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

Claude Code — single project

CLAUDE CODE — SINGLE PROJECT · TERMINAL

claude mcp add serena -- serena start-mcp-server --context claude-code --project "$(pwd)"

Claude Desktop

CLAUDE DESKTOP · JSON

{
  "mcpServers": {
    "serena": {
      "command": "serena",
      "args": [
        "start-mcp-server",
        "--context=desktop-app"
      ]
    }
  }
}

GitHub Copilot — JetBrains

GITHUB COPILOT — JETBRAINS · JSON

{
  "servers": {
    "serena": {
      "type": "stdio",
      "command": "serena",
      "args": [
        "start-mcp-server",
        "--context=jb-copilot-plugin"
      ]
    }
  }
}

VS Code

Run the MCP: Add Server command, select the Command (stdio) option, and enter the command below (workspace install; for the global install enter serena start-mcp-server --context=vscode).

VS CODE · TERMINAL

serena start-mcp-server --context=vscode --project ${workspaceFolder}

GitHub Copilot

GITHUB COPILOT · JSON

{
  "mcpServers": {
    "serena": {
      "type": "stdio",
      "command": "serena",
      "tools": [
        "*"
      ],
      "args": [
        "start-mcp-server",
        "--context=copilot-cli",
        "--project-from-cwd"
      ]
    }
  }
}

Codex

CODEX · TOML

[mcp_servers.serena]
startup_timeout_sec = 15
command = "serena"
args = ["start-mcp-server", "--project-from-cwd", "--context=codex"]

Grok CLI

GROK CLI · TERMINAL

grok mcp add --scope user serena -- serena start-mcp-server --context=grok --project-from-cwd

JetBrains AI Assistant

JETBRAINS AI ASSISTANT · JSON

{
  "mcpServers": {
    "serena": {
      "command": "serena",
      "args": [
        "start-mcp-server",
        "--context=jb-ai-assistant",
        "--project-from-cwd"
      ]
    }
  }
}

Antigravity

ANTIGRAVITY · JSON

{
  "mcpServers": {
    "serena": {
      "command": "serena",
      "args": [
        "start-mcp-server",
        "--context=antigravity"
      ]
    }
  }
}

CodeBuddy

CODEBUDDY · TERMINAL

serena setup codebuddy

Any MCP client

ANY MCP CLIENT · TERMINAL

serena start-mcp-server --context ide

Serena MCP

Pick the backend before you install: the free one does less.

What it is

What you get

Requirements

Setup effort

Changing a function that is called all over a large codebase

Editing one method without re-emitting the file

Understanding unfamiliar code before touching it

Restructuring a package

16 tools

What to know first

Tools you get

Connect your client

Server setup

MCP Clients

Claude Code

Claude Code — single project

Claude Desktop

GitHub Copilot — JetBrains

VS Code

GitHub Copilot

Codex

Grok CLI

JetBrains AI Assistant

Antigravity

CodeBuddy

Any MCP client

Serena MCP

Pick the backend before you install: the free one does less.

What it is

What you get

Requirements

Setup effort

Changing a function that is called all over a large codebase

Editing one method without re-emitting the file

Understanding unfamiliar code before touching it

Restructuring a package

16 tools

What to know first

Tools you get

Connect your client

Server setup

MCP Clients

Claude Code

Claude Code — single project

Claude Desktop

GitHub Copilot — JetBrains

VS Code

GitHub Copilot

Codex

Grok CLI

JetBrains AI Assistant

Antigravity

CodeBuddy

Any MCP client

Same category

code context engine

memtrace

codeix

ken