You do not need the towncrier CLI to contribute. Fragments are ordinary Markdown files; towncrier runs only when a release is prepared. See CONTRIBUTING.md.

Create a fragment

# Prefer the PR or issue number when you know it:
#   changelog.d/<number>.<type>.md
# Orphan (no linked issue/PR yet):
#   changelog.d/+.<type>.md   or   changelog.d/+short-slug.<type>.md

Types (Keep a Changelog)

Suffix	Section
`security`	Security
`removed`	Removed
`deprecated`	Deprecated
`added`	Added
`changed`	Changed
`fixed`	Fixed

Content

One or a few sentences of what shipped — behavior, docs, or install impact someone would care about in release notes. Link issues in the fragment body if useful; towncrier also links the number from the filename.

General reports no longer promote unanchored fallback entity misses into synthesis.

Skip

Pure chores (typos in comments, CI pin bumps with nothing for release notes) can omit a fragment and check Skip changelog in the PR template, or add the skip-changelog label.