dagster-io

Expert guidance for working with Dagster and the dg CLI. ALWAYS use before doing any task that requires knowledge specific to Dagster, or that references assets, materialization, components, data tools or data pipelines. Common tasks may include creating a new project, adding new definitions, understanding the current project structure, answering general questions about the codebase (finding asset, schedule, sensor, component or job definitions), debugging issues, or providing deep information about a specific Dagster concept.

Opinionated production Python standards with automatic version detection (3.10-3.13). Use when writing, reviewing, or refactoring Python in repos that want modern type syntax, explicit condition checks where practical, pathlib operations, interface guidance, and pragmatic production patterns.

This skill should be used when writing tests, fixing bugs, adding features, or modifying the gateway layer. Use when you need guidance on testing architecture, working with fakes, implementing ABC gateway interfaces, or understanding the defense-in-depth testing strategy. Essential for maintaining test quality and understanding where different types of tests belong.

Refactor tests that use unittest.mock.patch or MagicMock into erk's gateway-based fake pattern. Use when tests import unittest.mock, use @patch decorators, or directly call mock.patch() as context managers. Essential when test_*.py files patch module-level attributes like subprocess.run, shutil.which, os.environ, or other system calls. Covers both making source code injectable AND rewriting tests.

Expert guidance for writing documentation for the Dagster docs website. ALWAYS use before creating or updating documentation in the docs directory.