---

name: repo-development description: "Maintain the DVC repository itself: source layout, CLI command internals, focused test selection, optional dependency boundaries, lint/type config, and contribution pitfalls." disable-model-invocation: true metadata: disco-role: operating license: Apache 2.0

DVC Repository Development

Use this sub-skill when an agent is editing the DVC codebase rather than using DVC in an end-user project. It covers package layout, command implementation patterns, focused tests, optional dependency boundaries, and local quality checks for safe maintainer workflows.

Start Here

1. Identify the changed surface: CLI parser/command class, Repo method, Python API helper, filesystem/remote backend, config/schema, testing fixture, or docs-only change.
2. Read references/development-guide.md for the code layout, entry points, packaging facts, and command implementation flow before editing.
3. Use scripts/select_tests.py with changed file paths to propose focused pytest targets and marker exclusions without running tests.
4. Read references/test-selection.md before running tests; prefer narrow unit/functional targets and skip opt-in network, Studio, and VSCode contract markers unless explicitly needed.
5. Read references/troubleshooting.md when imports, optional backends, parser errors, config validation, or DVC test fixtures fail.

Maintainer Defaults

• Console entry point is dvc = dvc.cli:main; in this checkout dvc.cli is a package and the main implementation is dvc/cli/__init__.py.
• CLI commands are registered from dvc/cli/parser.py, implemented under dvc/commands/, and usually delegate business logic to dvc/repo/.
• Tests are not part of setuptools packages (tests, tests.* excluded; namespaces disabled), so runtime code must not import tests.*.
• Optional remote extras such as azure, gdrive, gs, hdfs, oss, s3, ssh, webdav, and webhdfs are not installed by default.
• Do not run the full test suite by default; start with focused paths and marker exclusions.

Bundled References

• references/development-guide.md explains source layout, package metadata, command wiring, editable install expectations, and local quality tooling.
• references/test-selection.md maps common changed files to focused test targets, marker policy, and safe no-network commands.
• references/troubleshooting.md covers dependency/import failures, parser errors, optional extras, flaky network/Studio tests, config warnings, and fixture mistakes.
• scripts/select_tests.py prints suggested pytest targets and marker exclusions from changed paths; it never imports DVC or runs pytest.

Routing Notes

• Route end-user data tracking, stages, dvc repro, and pipeline operation to ../data-and-pipelines/SKILL.md.
• Route end-user remotes, cache behavior, push/pull/fetch, and storage credentials to ../remotes-and-cache/SKILL.md.
• Route metrics, params, and plots usage to ../metrics-params-plots/SKILL.md.
• Route experiment workflows to ../experiments/SKILL.md.
• Route public Python API usage (dvc.api, DVCFileSystem, Repo automation) to ../python-api/SKILL.md unless the task is about changing those APIs inside the DVC repo.