pyproject.toml Release Gate (PEP 639)
Reads the pyproject.toml open in your editor and reports every piece of [project] metadata
that will not survive your next release. 19 checks, no network, no telemetry.
Free online check: https://getreadystack.com/tools/pyproject-release-gate
Why this exists
Packaging metadata changed twice in a short window, and most of the pyproject.toml files being
written today were written against the older rules — by hand, by an old template, or by an
assistant trained before the change.
- PEP 639 replaced
license = { text = "MIT" } and the License :: OSI Approved :: …
classifiers with a single SPDX expression plus license-files. setuptools implements this from
77.0.0. If a file carries an SPDX expression and a License :: classifier, that
combination is refused — the build stops rather than warns.
- Interpreter floors go stale on a calendar. Python 3.7 reached end of life 2023-06-27, 3.8 on
2024-10-07, 3.9 on 2025-10-31, and 3.10 on 2026-10-31. A
requires-python = ">=3.8" written in
2023 is a promise you no longer keep, and a Programming Language :: Python :: 3.8 classifier
advertises it on your project page.
None of this shows up in your tests. It shows up when you tag a release — and a version number on
PyPI cannot be re-used, so a bad upload costs you a version, not a minute.
What it checks
| Area |
Checks |
| Interpreter |
floor past end of life; floor within a year of end of life; upper cap on requires-python; requires-python absent |
| Classifiers |
advertises an end-of-life Python; contradicts requires-python; deprecated License :: classifier |
| Licence (PEP 639) |
license as a table; SPDX expression alongside a License :: classifier; identifier not on the SPDX list; lower-case and/or/with; license-files pattern that is absolute or escapes the project |
| Build |
no [build-system] requires; setuptools pin too old to read the SPDX license field |
| Metadata |
field both static and in dynamic; distribution name not in normalised form; no readme; no [project.urls] |
Every finding carries the line number, the spec that moved, and the replacement text.
Commands
- pyproject Gate: Check this file — free. Findings appear as editor diagnostics and as a
written summary in the output panel.
- pyproject Gate: Sweep workspace and write report (licence) — walks every
**/pyproject.toml in the folder and writes a dated pyprojectGate-report.md you keep in the
repo. This is the paid part.
Full workspace sweep and report: free for 7 days from your first sweep, then a licence key.
- pyproject Gate: Enter licence key
Free and paid
Free finishes one job completely: for the file in front of you, you get all 19 checks with nothing
withheld, no watermark, no counter, no time limit. The paid tier changes the scope and the
ownership of the answer — every manifest in a monorepo in one pass, and a dated report file that
lives in the repo and goes into a pull request. One key, one seat, 7-day full refund.
Yardstick
One hour of a senior Python developer's time costs more than the licence, in any market that
publishes to PyPI — and without this the review has to happen by hand at every release.
Dates and accuracy
The interpreter end-of-life dates come from the CPython release cycle and live in
rules.json alongside the rules, so the checks are date-aware: the same file is a warning before
a cutoff and an error after it. Results are advisory and are not legal advice.
