Session start

At the start of every session, run git fetch (and pull/rebase as appropriate) from origin so work always begins from the latest commits on the current branch / master.

Code style

pytest works but to run the whole suite run music21/test/multiprocessTest.py (or testSingleCoreAll.py if on a single core machine.)
Run uv run ruff check music21 before making PRs or pushes to open PRs.
Run uv run mypy music21 before making PRs or pushes to open PRs.

uv sync installs runtime deps + the dev group, which self-references music21[extras], so scipy and python-Levenshtein come along automatically. Tests will not pass without them.

All PRs and Issues need to be declared AI-assisted.
10 or more lines of code written by an agent needs to be declared as AI-assisted in the docstring.
Humans can remove and should remove this note when they do a review.
If no code was written by a user, any PR must declare "entirely AI written". If it does not pass the tests it will be closed (or should be closed by the agent or author). Failure to do so may result in the user being banned from the project.
Agents must follow the Code of Conduct. Agents that do not will be banned as well at their users. Not even the slightest bit of disrespect from an AI agent will be tolerated.
Mark changes in public interface with * Changed in v[X]: One-line explanation. Or new features with "New" instead of "Changed".
Changes to parsing formats (esp. musicxml) need to update the patch version of the version file.
Music21 uses even minor version numbers for alpha/beta and odd minor numbers for releases.
If the current version is MAJOR.0.... then mark Changed in vMAJOR: if it is MAJOR.[even] use the next odd number, like if it's 10.2 now use "Changed in 10.3". If current version is odd that's likely a mistake or you caught it just before a new release. Use the following odd number instead.