Downstream compatibility consumers

These are three maintained reference consumer fixtures used as compatibility evidence. They are deliberately separate packages with separate names, entry points, and test suites; none imports another fixture or Base product code. They are not independent adopters and must not be presented as customer outcomes.

Consumer	Shape	Use case	Compatibility outcome
Atlas	Existing Click group	Inventory/status automation	Existing tree remains intact after attach().
Beacon	Typed Typer app	Deployment command	Typer validation/help remains native through attach_typer().
Cinder	Native App	Scheduled reconciliation	Dry-run and JSON output are deterministic and safe.

How the evidence is retained

scripts/validate_consumers.py validates the manifest, package metadata, and required compatibility documentation. The Reference consumers workflow builds and installs the base-cli wheel first, installs each consumer with its own dependencies, and runs each consumer's tests. This catches import, packaging, adapter, and contract regressions without relying on repository source imports.

The downstream job records a dated JSON result as the base-cli-compatibility-evidence-<run-id> artifact. It binds the result to the framework revision and version and lists the exact fixture and matrix that passed. See adoption-evidence.md for the claim and permission boundary.

The same workflow runs the Typer adapter and Beacon fixture against Typer 0.25.1, 0.26.0, and 0.27.1 on Python 3.10 through 3.14. This matrix covers the transition from Click's public command classes to Typer's vendored Click fork.

Run the same checks locally:

python scripts/validate_consumers.py
python -m build --wheel
python -m pip install dist/base_cli-*.whl
for consumer in compatibility/consumers/*; do python -m pip install "$consumer"; done
for tests in compatibility/consumers/*/tests; do python -m pytest "$tests"; done

The fixtures are not customer claims. A permissioned public adopter can be added as a separate record while retaining the same downstream contract tests.