The knowledge in these reference files is derived from three upstream projects. When in doubt, always defer to these sources over anything written here.

1. `canonical/chisel` (tool behaviour)

The Go source code defines what chisel actually does: how it parses SDFs, resolves dependencies, extracts files, runs mutate scripts, handles wildcards, and validates fields. The tool's behaviour is the ultimate arbiter of what is valid.

Repo: https://github.com/canonical/chisel
Key paths: internal/setup/ (SDF parsing), internal/slicer/ (slice cutting logic)

2. `canonical/chisel-docs` (official documentation)

The documentation source renders to https://documentation.ubuntu.com/chisel/en/latest/. It is the authoritative reference for SDF format, CLI usage, and slicing workflows.

Repo: https://github.com/canonical/chisel-docs
Raw page access pattern: https://raw.githubusercontent.com/canonical/chisel-docs/main/docs/<path>.md; rendered at https://documentation.ubuntu.com/chisel/latest/<path>/
Key pages:
- how-to/slice-a-package.md -- canonical slicing workflow
- reference/chisel-releases/slice-definitions.md -- SDF format specification
- reference/chisel-releases/chisel.yaml.md -- release config schema (format versions, archives, maintenance)
- explanation/slice-design-approaches.md -- grouping-by-content vs grouping-by-function
- explanation/slices.md -- conceptual overview of slices
- reference/cmd/cut.md -- chisel cut CLI reference
- reference/manifest.md -- manifest format
- how-to/install-pro-package-slices.md -- pro slices

3. `canonical/chisel-releases` (existing slices & conventions)

The collection of published SDFs is the ground truth for conventions, naming patterns, and reviewer expectations. Studying real SDFs is more reliable than any written convention doc.

Repo: https://github.com/canonical/chisel-releases
Key files on each release branch: chisel.yaml, slices/bash.yaml, slices/base-files.yaml
main carries what the release branches do not: CONTRIBUTING.md, README.md with the live release-branch list, .github/yamllint.yaml, and the reusable CI workflows plus the scripts they drive (.github/scripts/validate-hints/, install-slices/, removed-slices/, pkg-deps/). A release branch's own .github/workflows/ci.yaml only calls into them, so read the definitions on main

Also: chisel-releases navigator https://canonical.github.io/chisel-releases-navigator/; Ubuntu release schedule https://wiki.ubuntu.com/Releases.

Precedence

When sources conflict: tool behaviour > chisel-docs > chisel-releases conventions > these reference files.

When a reference file disagrees with the repo, trust the repo. When in doubt, read slices/bash.yaml or slices/base-files.yaml on the target release branch.