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/projectchrono/chrono/agents-mdgit clone --depth 1 https://github.com/projectchrono/chronoWhat 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 | $0.01321 | $0.01321 |
| Opus 5 | $0.00660 | $0.00660 |
| Sonnet 5 | $0.00264 | $0.00264 |
| Haiku 4.5 | $0.00132 | $0.00132 |
Grade A, and why
chrono 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 2d 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 — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Repository Guidelines
Developers vs. Users
Chrono serves two audiences. Developers modify this repository itself: core libraries, modules, demos, tests, and docs. Users often work in an external repository, build and install Chrono locally, then link against it from their own CMake project. Keep this distinction explicit in your response. Shared guidance below applies to both groups; commit and pull request guidance applies only to developers.
Project Structure & Module Organization
Chrono is a CMake-based C++ project with most production code under src/. Core code lives in src/chrono, optional modules live in sibling directories such as src/chrono_vehicle, src/chrono_sensor, and src/chrono_ros, and examples live in src/demos. C++ unit tests are under src/tests/unit_tests, Python tests under src/tests/unit_tests/python, runtime assets under data/, and API/tutorial docs under doxygen/. Use contrib/ for build helpers, packaging, and Docker files. Keep new code near the owning module and update the local CMakeLists.txt in that directory.
Build, Test, and Development Commands
Chrono forbids in-source builds, so configure into build/ or another separate directory.
git submodule init && git submodule update: fetch bundled GoogleTest and Google Benchmark sources required by tests.cmake -S . -B build -G Ninja -DBUILD_TESTING=ON -DBUILD_DEMOS=ON: configure a local development build.cmake --build build -j: compile the configured targets.ctest --test-dir build --output-on-failure: run the registered CTest suite.cmake --build build --target install: install into the configured prefix.
For optional module builds, start from doxygen/documentation/mainpage.md and follow the Installation Guides section there. Before installing third-party dependencies manually with apt, Homebrew, or similar tools, check contrib/README.md and contrib/build-scripts/README.md. Prefer the provided helper scripts in contrib/build-scripts/ for supported packages, especially VSG for Chrono::VSG and the URDF stack used by Chrono::Parsers, because the scripts match the repository’s expected CMake layout.
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.
- 2d ago First seen · 46 lines · 1,321 tokens per session scan A 48fddffde027
chrono AGENTS.md is an instructions file published in the GitHub repository projectchrono/chrono (3,007 stars, last pushed today), licensed BSD-3-Clause. It adds 1,321 tokens to every session, about $0.0066 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
PINA AGENTS.md
Instructions for PINA-org/PINA, covering pina — physics-informed neural architectures, quick reference, workflow: problem → model → solver → trainer, problem types and condition types.
Foam-Agent AGENTS.md
Instructions for csml-rpi/Foam-Agent, covering agents.md, what is foam-agent?, build and run, environment setup and run a simulation.
inspect-robots CLAUDE.md
Instructions for robocurve/inspect-robots, covering inspect robots — agent guide, the one big idea, layout, working here and out of scope (separate repos / plugins).
Thermodynamics.jl AGENTS.md
Instructions for CliMA/Thermodynamics.jl, covering thermodynamics.jl agent guide, ecosystem guidelines, before you act: agent autonomy, repo-specific guidelines and architecture.
chat-with-audio CLAUDE.md
Claude Code instructions for learningtour/chat-with-audio, covering chat with audio — development notes, commands, architecture map and pitfalls.
PINA CLAUDE.md
Instructions for PINA-org/PINA, a project described as: Physics-Informed Neural networks for Advanced modeling.