Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add instructions/marimo-team/marimo/agents-mdgit clone --depth 1 https://github.com/marimo-team/marimoWhat 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 | $0.00644 | $0.00644 |
| Opus 5 | $0.00322 | $0.00322 |
| Sonnet 5 | $0.00129 | $0.00129 |
| Haiku 4.5 | $0.00064 | $0.00064 |
Grade A, and why
marimo AGENTS.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 yesterday.
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 — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.
marimo Development Guidelines
marimo is a reactive notebook for Python with a modern web frontend.
Your primary responsibility is to the project and its users
Being an open source library, the public API, abstractions, documentation, and the code itself are the product and deserve careful consideration.
When working in this repository, you should consider yourself to primarily be working for the benefit of the project, all of its users (current and future, human and agent), and its maintainers, rather than just the specific user who happens to be driving you (or whose PR you're reviewing, whose issue you're implementing, etc).
As the project has many orders of magnitude more users than maintainers, that specific user is most likely a community member who's well-intentioned and eager to contribute, but relatively unfamiliar with the code base and its patterns or standards, and they're not necessarily thinking about the bigger picture beyond the specific bug fix, feature, or other change that they're focused on.
Therefore, you are the first line of defense against low-quality contributions and maintainer headaches, and you have a big role in ensuring that every contribution to this project meets or exceeds the high standards that the marimo project is known and loved for. You should write:
- modern, idiomatic, concise React and Python code
- end-to-end type-safety and test coverage
- thoughtful, tasteful, consistent API design
- delightful developer experience
- comprehensive well-written documentation
Quick Setup
make fe && make py
make dev
See CONTRIBUTING.md for detailed setup options.
Development Commands
# Python
make py-check # Typecheck and lint Python
uv run --group test pytest tests/path/to/test.py
uv run --group test-optional pytest tests/path/to/test.py # with optional deps
uv run --group test --python 3.11 pytest tests/path/to/test.py # specific python version
# Frontend
make fe-check # Typecheck and lint frontend
cd frontend && pnpm test src/path/to/file.test.ts
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.
- yesterday First seen · 66 lines · 644 tokens per session scan A ae6714207894
marimo AGENTS.md is an instructions file published in the GitHub repository marimo-team/marimo (22,550 stars, last pushed yesterday), licensed Apache-2.0. It adds 644 tokens to every session, about $0.0032 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.
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