---
id: libcst
version: "1.9.0"
license: All contributions towards LibCST are MIT licensed. Some Python files have been derived from the standard library and are therefore PSF licensed. Modifications on these files are dual licensed (both… (full text in the JSON record)
license_treatment: permissive
maintenance: active
---

# libcst — A concrete syntax tree with AST-like properties for Python 3.0 through 3.15 programs.

License: permissive · Maintenance: active · Popularity: top 1,000 on PyPI

## Install

pip install libcst
uv add libcst
poetry add libcst

## Description

.. image:: docs/source/_static/logo/horizontal.svg
   :width: 600 px
   :alt: LibCST

A Concrete Syntax Tree (CST) parser and serializer library for Python

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## AI interpretation — verify before relying

LibCST parses Python 3.0–3.15 source code into a lossless Concrete Syntax Tree that preserves all formatting (comments, whitespace, parentheses), enabling automated refactoring and linting tools to read and modify code while maintaining exact formatting.

Verdict: LibCST is a well-maintained, actively developed parser for building code transformation tools. Its lossless CST design and broad Python version support (3.9–3.15) make it suitable for production refactoring and linting. Medium install friction from native compilation is offset by prebuilt wheels for common platforms and zero known vulnerabilities.

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