SciRecast

An open-source, agentic ecosystem for modernizing legacy scientific software.

LLM agents do the labor-intensive porting work under human oversight; every artifact ships only after passing correctness validation and security review. This repository is the entry point, and it contains exactly two things:

Submodule	What it is
RecastEngine	The modernization engine — the reusable, domain-independent part of SciRecast.
CESM-modernization-overview	Our first case: modernizing CESM/CAM, the community Earth-system model. Every Support- and Product-Layer component lives in there, as its own submodule.

Run git submodule update --init --recursive to populate both.

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The Three Layers, Seen Through the CESM Case

SciRecast is organized into three layers. Humans maintain the inner two (the engine, and the validation & security infrastructure); the agent produces the outermost one — and only after the artifact passes the gates.

flowchart TB
    subgraph Product["🟦 Product Layer — modernized software (CESM case)"]
        PyCAM5["PyCAM5 · freeCAM · PyCCPP"]
        JaxCAM6["JaxCAM6 · NumbaCAM6"]
    end
    subgraph Support["🟩 Support Layer — Validation & Security"]
        CCTest["CC-Test"]
        SecTrack["Sec-Track"]
    end
    subgraph Core["🟥 Core Layer — RecastEngine"]
        Engine["multi-LLM-agent, neuro-symbolic"]
    end

    Engine -- "translate · refactor · port to accelerators" --> Product
    Engine -- "retrieve for correctness validation" --> CCTest
    Engine -- "store security analyses" --> SecTrack
    CCTest -- "gate" --> Product
    SecTrack -- "gate" --> Product

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🟥 Core Layer — RecastEngine. A multi-LLM-agent engine that combines the generative power of LLMs with the rigor of formal methods (neuro-symbolic). It translates languages, refactors architectures, ports code to accelerators, retrieves CC-Test for correctness validation, and stores security analyses to Sec-Track. In the CESM case it drives the deterministic Fortran → Python translation pipeline (SymPy-based); the ZM and MG2 schemes are verified bit-exact.

🟩 Support Layer — the trust foundation. CC-Test is a CI/CD workflow covering both Correctness and Cyber testing; its Cyber half is a working DevSecOps gate (secret scanning, SBOM + CVE + VEX, AI code audit, sanitizer builds), verified on NCAR's Derecho. Sec-Track is a restricted-access record of N-day and responsibly disclosed 0-day vulnerabilities across the software, its supply chain, and its runtime.

🟦 Product Layer — the modernized software itself. For CESM this runs as two pipelines: CAM5 rewritten to modular Python (PyCAM5, freeCAM, PyCCPP), and CAM6 physics kernels ported to GPUs (JaxCAM6, NumbaCAM6).

Both of these layers are assembled in the case repository — see CESM-modernization-overview for the component repositories, per-scheme progress, and validated-run evidence.

Contribution model. Human developers do not directly modify the Product Layer. When end users open issues, RecastEngine generates, tests, and merges the fixes. Humans contribute to the Core Layer (new formal methods and agentic designs) and to the Support Layer (benchmark suites, validation workflows, vulnerability reports).

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Contributing & Contact

See CONTRIBUTING.md. Bug reports and feature ideas go to the relevant component repository. Security vulnerabilities: please do not open a public issue — use a private GitHub security advisory or email Yueqi Chen (University of Colorado Boulder), yueqi.chen@colorado.edu.

License

Apache License 2.0 — see LICENSE and NOTICE. Two exceptions: legacy code retained inside modernized software keeps its original license (documented in each component's NOTICE), and Sec-Track access is restricted to reduce exploitation risk.