PEP 723 - Inline Script Metadata

PEP 723 introduces a metadata format that can be embedded in single-file Python scripts. This assists launchers, IDEs, and other tools that need to interact with these scripts, providing information such as dependencies and supported Python versions.

Motivation:
Python is often used for scripting, but there is no standard way to define metadata for these scripts. This PEP aims to standardize the way metadata is embedded within scripts, making it easier for tools to understand and execute them.

Rationale:
The metadata is embedded within the script itself, similar to the pyproject.toml format, providing a consistent experience for users. This avoids the need for separate files and ensures the script remains self-contained.

Specification:

Metadata blocks start with # /// TYPE and end with # ///.
The content between these lines must be comments.
The first type of metadata block is named script, containing fields like dependencies and requires-python.
Tools must produce an error if they encounter multiple blocks of the same type.

Example:

# /// script
# requires-python = ">=3.11"
# dependencies = [
#   "requests<3",
#   "rich",
# ]
# ///
import requests
from rich.pretty import pprint

resp = requests.get("https://peps.python.org/api/peps.json")
data = resp.json()
pprint([(k, v["title"]) for k, v in data.items()][:10])

You can run script using this inline metadata using uv run <my-script.py> from Python UV.