Dagster is a platform for developing, running, and observing data assets, such as datasets and the processes that produce them. It is used to organize and automate data workflows.
Borrowing it
Nothing to install: this file belongs to dagster-io/dagster. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/dagster-io/dagster/master/CLAUDE.mdgit clone --depth 1 https://github.com/dagster-io/dagsterWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/dagster-io/dagster/claude-md)<a href="https://agentmods.dev/instructions/dagster-io/dagster/claude-md"><img src="https://agentmods.dev/badge/instructions/dagster-io/dagster/claude-md.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01210 | $0.01210 |
| Opus 5 | $0.00605 | $0.00605 |
| Sonnet 5 | $0.00242 | $0.00242 |
| Haiku 4.5 | $0.00121 | $0.00121 |
Grade A, and why
dagster CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Dagster Development Guide
Quick References
- Package Locations: .claude/python_packages.md - Comprehensive list of all Python packages and their filesystem paths. ALWAYS check this file first when looking for package locations.
- Development Workflow: .claude/dev_workflow.md - Documentation of developer workflows in the Dagster OSS repo.
- UI Workflow: .claude/ui_workflow.md - UI/TypeScript development workflows and verification commands. ALWAYS check after UI edits.
- Coding Conventions: .claude/coding_conventions.md - Type annotations and code style conventions. ALWAYS check this before writing data structures - use @record instead of @dataclass.
- CRITICAL: After ANY Python code changes, ALWAYS run
just ruff- this is mandatory and must never be skipped.
Environment Setup
See docs/docs/about/contributing.md for full setup instructions.
just dev_install # Full development environment setup
Essential Commands
# Code quality - RUN AFTER EVERY PYTHON EDIT
just ruff # Format, lint, and autofix code - MANDATORY AFTER ANY CODE CHANGES
just ty # Type checking (slow first run)
just quick-ty # Type check only changed files
# Testing
pytest path/to/tests/ # Run specific tests
pytest python_modules/dagster/dagster_tests/ # Run core tests
tox -e py39-pytest # Test in isolated environment
# UI Verification (run from js_modules/ when done with edits)
cd js_modules
just generate-graphql # Regenerate GraphQL types (if schema changed; must run before tsgo/lint)
yarn tsgo # TypeScript checking
yarn lint # ESLint checking
yarn jest # Jest tests
yarn build # Verify production build (ui-components changes only)
# Development
just rebuild_ui # Rebuild React UI after changes
just generate-graphql # Regenerate GraphQL schema and codegen clients
just sanity_check # Check for non-editable installs
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 8d ago First seen · 121 lines · 1,210 tokens per session scan A 20b8c637f7d4
dagster CLAUDE.md is an instructions file published in the GitHub repository dagster-io/dagster (16,122 stars, last pushed 3d ago), licensed Apache-2.0. It adds 1,210 tokens to every session, about $0.0060 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
codex AGENTS.md
AGENTS.md instructions for openai/codex, covering rust/codex-rs, the codex-core crate, code review rules, crate api surface and model visible context.
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, applying the notice (cutover) and fallback chain (never fail the build).
spec-kit AGENTS.md
AGENTS.md instructions for github/spec-kit, covering agents.md, about spec kit and specify, quickstart — add a new integration in 5 steps, integration architecture and integrationmanifest — file tracking.