single-file-uv-scripter

Single-File UV Scripter

Creates self-contained Python scripts with inline dependency declarations per PEP 723. Scripts execute via uv run script.py with automatic dependency resolution.

Inline Metadata Format

# /// script
# dependencies = [
#   "package-name",
#   "package>=1.0,<2.0",
# ]
# requires-python = ">=3.12"
# ///

Syntax Rules

Element	Format	Required
Open marker	# /// script	Yes
Close marker	# ///	Yes
Dependencies	TOML array, each line # prefixed	Yes (can be empty [])
Python version	requires-python = ">=3.X"	Recommended

UV-Specific Extensions

# /// script
# dependencies = ["requests"]
# requires-python = ">=3.12"
# [tool.uv]
# exclude-newer = "2024-01-15T00:00:00Z"
# ///

• exclude-newer: RFC 3339 timestamp for reproducible builds (pins to releases before date)
• index: Alternative PyPI index URL

Template

#!/usr/bin/env -S uv run
# /// script
# dependencies = [
#   "DEPENDENCY",
# ]
# requires-python = ">=3.12"
# ///
"""One-line description of script purpose."""
from __future__ import annotations

# imports here

def main() -> None:
    """Entry point."""
    pass

if __name__ == "__main__":
    main()

Commands

Action	Command
Initialize	uv init --script name.py --python 3.12
Add dep	uv add --script name.py 'pkg>=1.0'
Run	uv run name.py [args]
Make executable	chmod +x name.py then ./name.py

Shebang Options

#!/usr/bin/env -S uv run                    # Standard
#!/usr/bin/env -S uv run --quiet            # Suppress UV output
#!/usr/bin/env -S uv run --python 3.12      # Pin Python version

Common Patterns

CLI with Arguments

#!/usr/bin/env -S uv run
# /// script
# dependencies = ["typer>=0.9", "rich"]
# requires-python = ">=3.12"
# ///
import typer
app = typer.Typer()

@app.command()
def main(name: str) -> None:
    print(f"Hello {name}")

if __name__ == "__main__":
    app()

HTTP Client

#!/usr/bin/env -S uv run
# /// script
# dependencies = ["httpx>=0.27"]
# requires-python = ">=3.12"
# ///
import httpx

def main() -> None:
    r = httpx.get("https://api.example.com/data")
    print(r.json())

if __name__ == "__main__":
    main()

Data Processing

#!/usr/bin/env -S uv run
# /// script
# dependencies = ["polars>=1.0", "rich"]
# requires-python = ">=3.12"
# ///
import polars as pl
from rich import print

def main() -> None:
    df = pl.read_csv("data.csv")
    print(df.describe())

if __name__ == "__main__":
    main()

Constraints

• Metadata block MUST appear before any Python code (after shebang/encoding is OK)
• Project dependencies are IGNORED when running inline-metadata scripts
• Each script is isolated: deps resolved fresh per script
• Empty deps array required if no dependencies: dependencies = []

Workflow

1. Create: Write script with inline metadata block
2. Test: uv run script.py (UV auto-installs deps)
3. Iterate: uv add --script script.py 'new-pkg' to add deps
4. Deploy: Script is self-contained, copy anywhere with UV installed

Type Checking

Standard pyright fails on PEP 723 scripts because inline deps aren't in pyproject.toml.

Run pyright with script's dependencies:

uvx --from pyright --with typer --with rich pyright script.py

Replace --with args with the script's actual dependencies.

Auto-extract deps and type-check:

script="path/to/script.py"
deps=$(python3 -c "
import re, tomllib
with open('$script') as f: c = f.read()
m = re.search(r'# /// script\n(.*?)\n# ///', c, re.DOTALL)
if m:
    t = '\n'.join(l.lstrip('# ') for l in m.group(1).split('\n'))
    print(' '.join('--with ' + re.split(r'[<>=!]', d)[0] for d in tomllib.loads(t).get('dependencies', [])))
")
eval "uvx --from pyright $deps pyright $script"