Borrowing it
Nothing to install: this file belongs to PKU-YuanGroup/OpenAI4S. 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/PKU-YuanGroup/OpenAI4S/main/CLAUDE.mdgit clone --depth 1 https://github.com/PKU-YuanGroup/OpenAI4SWrote 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/pku-yuangroup/openai4s/claude-md)<a href="https://agentmods.dev/instructions/pku-yuangroup/openai4s/claude-md"><img src="https://agentmods.dev/badge/instructions/pku-yuangroup/openai4s/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/pku-yuangroup/openai4s/claude-md"><img src="https://agentmods.dev/badge/instructions/pku-yuangroup/openai4s/claude-md.svg" alt="Reviewed on agentmods" width="80" 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 | $0.07525 | $0.07525 |
| Opus 5 | $0.03762 | $0.03762 |
| Sonnet 5 | $0.01505 | $0.01505 |
| Haiku 4.5 | $0.00752 | $0.00752 |
Grade A, and why
OpenAI4S CLAUDE.md scanned grade A with 1 finding 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 3d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
**Core is zero-dependency by design.** The engine, the LLM client (over `urllib`), and the web server (`http.server` + a hand-rolled WebSocket) use only the Python standard library. This is a hard constraint — see conven How it starts
The opening of the file, as written. The whole thing — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md / AGENTS.md
This file provides shared guidance to both Claude Code (CLAUDE.md) and Codex (AGENTS.md, symlinked to this file) when working with code in this repository.
Keep future guidance platform-neutral unless a section explicitly calls out a Claude Code- or Codex-specific workflow.
What this is
OpenAI4S is a pure-stdlib hybrid scientific research agent: provider-native JSON Tool calls form the orchestration/permission control plane, while persistent Python/R Code-as-Action kernels form the scientific execution plane. Python can call the in-kernel host singleton synchronously mid-cell; R is an independent analysis channel.
Core is zero-dependency by design. The engine, the LLM client (over urllib), and the web server (http.server + a hand-rolled WebSocket) use only the Python standard library. This is a hard constraint — see conventions below.
Commands
./setup.sh # one-time: locked lightweight .venv + pre-commit hook
./setup.sh --with-kernel-envs # also create comprehensive Python + R envs
./setup.sh --update-kernel-envs # sync existing Python + R envs, without pruning
./start.sh # launch daemon + web UI at http://127.0.0.1:8760/
uv run pytest # full offline test suite (LLM is mocked — no network, no keys)
uv run pytest -n auto --maxprocesses=4 --dist loadfile # the same suite, the way CI runs it (~7min vs ~20min)
uv run pytest tests/test_agent.py::test_max_turns_stop # a single test
uv run pytest tests/test_kernel.py -k background # tests matching a pattern
uv run mypy # strict agent/Host + orchestration contracts
uv run pre-commit run --all-files # format + lint + mypy (black · isort --profile black · ruff)
uv run openai4s run "…" -v # run one Code-as-Action task in-process, no daemon
openai4s setup --profile standard # build Python + R from envs/*.yml
openai4s setup # build all 4 envs (--dry-run to preview)
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.
- 3d ago Changed · +1 lines · +22 tokens per session d1c96665990b
- 7d ago Changed · +6 lines · +456 tokens per session f6419c38c495
- 10d ago First seen · 130 lines · 7,047 tokens per session scan A 0e9159dbe31f
OpenAI4S CLAUDE.md is an instructions file published in the GitHub repository PKU-YuanGroup/OpenAI4S (399 stars, last pushed yesterday), licensed MIT. It adds 7,525 tokens to every session, about $0.0376 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
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.
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).
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.
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).
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.