Imported from XKNX/xknx (AGENTS.md). Install upstream with npx skills add XKNX/xknx. Copyright stays with the author.

xknx contributor conventions

Referencing the KNX Standard

Code comments, docstrings and commit/PR text in this repo frequently cite a specific part of the KNX Standard to justify a byte layout, a state machine, or a piece of protocol behavior. These citations must be traceable back to an exact document and an exact version of that document.

Format

KNX v<version> - <Document Title> <document number> - §<paragraph>

Examples from the codebase:

KNX v02.01.02 - Management Procedures 03.05.02 - §2.19
KNX v01.02.02 - Transport Layer 03.03.04 - §2 TPDU

Why the version matters

The KNX Standard is published as a set of separate documents (one per volume/part/chapter), and different documents carry different version numbers — they are not all released together under one overall version. Transport Layer (03.03.04) is at v01.02.02, while the Management Procedures document (03.05.02) is at v02.01.02. A citation with the document number but no version is ambiguous: the cited paragraph's content, numbering, or even its existence can differ between versions of the same document.

Rule: never guess the version (or the document number/title)

If you (Claude) are adding or fixing a spec citation and don't already have the version number confirmed for that specific document, stop and ask the user rather than filling in a plausible-looking version, inferring it from a different document, or reusing another citation's version "for consistency." The same applies to the document title and number themselves if they aren't already established elsewhere in the codebase.

Known documents and confirmed versions

Note that Management Procedures and Application Layer are two different documents, cited side by side in places, that carry different versions (v02.01.02 vs v02.01.01) — don't assume every KNX document shares one "current" version just because two happen to be close.

How the KNX Standard is organized

The KNX Standard is split into numbered Volumes, each covering a different area; a document's number starts with its Volume:

Almost everything xknx cites is Volume 3, since that's the wire protocol itself. Volume 10 documents are extensions layered on top (e.g. LTE adds A_GroupPropValue_* services on top of the Application Layer) and are versioned independently of Volume 3 — this is why Logical Tag Extended (10.01) doesn't share a version with Application Layer (03.03.07) even though the two are closely related.

Document numbers within a volume follow <volume>.<chapter>[.<subchapter>] (e.g. 03.03.07 = Volume 3, chapter 3, subchapter 7). The chapter/ subchapter structure doesn't tell you the version — two documents in the same volume, even adjacent subchapters, can still be at different versions (e.g. Transport Layer 03.03.04 at v01.02.02 vs. Application Layer 03.03.07 at v02.01.01), so the numbering scheme is only useful for finding which document to ask about, never for guessing its version.

Every segment is zero-padded to two digits — 03.08.02, not 3.8.2; 10.01, not 10.1 — matching the KNX Association's own document filenames (e.g. 03_08_02 Core, 10_01 Logical Tag Extended). Write new citations this way even where an existing one in the codebase doesn't.

Management procedures naming convention

xknx/management/procedures/ implements KNX management procedures (DM_, NM_, ...). The full convention — package layout, the workflow for adding a new procedure, and the two function forms every procedure comes in — is documented in the package docstring at xknx/management/procedures/__init__.py; that's the canonical version, kept in sync with the code. Summary:

• <spec_name>(xknx: XKNX, ...) opens (and closes) its own connection or broadcast via xknx.management.
• <spec_name>_conn(conn: P2PConnection, ...) operates on an already-open connection, for chaining several procedures over one connection. The _conn suffix is an xknx-only naming convention, not a KNX spec name — dm_restart_r_co is the one exception, since RCo is the real KNX name for that connection-based variant of DM_Restart.

Running tests and checks

The project is managed with uv; dependencies are declared in pyproject.toml ([project].dependencies for the library, [dependency-groups] dev for tooling) and pinned in uv.lock. There is no requirements.txt and no tox.

uv sync                        # create/update the environment
uv run pytest                  # unit tests
uv run prek run --all-files    # ruff, ruff format, mypy, pylint, codespell
uv run --python 3.11 pytest    # test against another supported version

Hooks are configured in .pre-commit-config.yaml and run by prek. Never add a tool version to that file — linters run from the locked project environment via uv run --frozen, so uv.lock is the only place their versions live.

Changelog

Every user-facing change belongs in docs/changelog.md, under the # Unreleased changes heading at the top of the file (a new numbered release heading and date are added by the maintainer at release time, not by a PR). Group entries under a ### <Category> heading matching what's already used nearby — common ones are Protocol, DPT, Devices, Connection, New Features, Breaking Changes, Deprecation notes, and Internals for anything with no user-visible behavior change. Breaking changes should include a short before/after code snippet, not just prose.

Pull requests

Copy .github/pull_request_template.md for the PR description — don't write a free-form description instead. Fill in the "Description", "Type of change" and "Checklist" sections for real (tick what actually applies, don't leave every box checked or unchecked by default).