Yes—**reuse the existing C++ core and expose it to Python via bindings**. This is the cleanest way to speed up hot paths while keeping Python as the orchestration layer and preserving GrowNet’s determinism and API contract.

Below is a concrete, drop‑in plan that you can hand to Codex (or implement directly).

------

## What we’ll do

- Keep the **C++ codebase authoritative** for heavy compute (slot selection, windowed wiring, proximity spatial hash, etc.).
- Provide a **thin Python wrapper** using **pybind11** (or nanobind) that:
  - Mirrors the **snake_case** public API (no leading underscores).
  - Releases the **GIL** around heavy kernels.
  - Moves arrays via **NumPy buffers** without copies.
  - Routes all stochastic choices through the **Region RNG** (no fallback RNG).
- Ship Python wheels using **scikit‑build‑core + CMake**, so users `pip install grownet_native` on Linux/macOS/Windows.

------

## File layout (proposed)

```
/src
  /cpp
    /core              # your current C++ sources (unchanged)
    /bindings
      grownet_pybind.cpp
  /python
    grownet_native/
      __init__.py      # public Python API surface, snake_case
      interop.py       # helper validators for arrays (dtype, shape)
      rng.py           # seed/set/get wrappers that call into C++
pyproject.toml
CMakeLists.txt
```

------

## Minimal binding surface (start small, expand safely)

Expose just enough to accelerate hot paths while keeping the Python contract unchanged:

### 1) Region & Bus

- `Region(name: str)`
- `add_input_layer_2d(height, width) -> int`
- `add_output_layer_2d(height, width, bias=0.0) -> int`
- `connect_layers_windowed(src_index, dst_index, kernel_h, kernel_w, stride_h, stride_w, padding, feedback) -> int`
- `tick_2d(frame: np.ndarray[float32|float64, C-contiguous])`
- `bus.get_current_step() -> int`

*(Match your existing C++ function names with a thin snake_case alias to keep Python style consistent.)*

### 2) Optional helpers (for proximity policy & tests)

- `has_edge(src_layer, src_neuron, dst_layer, dst_neuron) -> bool`
- `connect_neurons(src_layer, src_neuron, dst_layer, dst_neuron, feedback=False) -> None`
- `record_mesh_rule_for(src_layer, dst_layer, probability=1.0, feedback=False) -> None`
- `get_layer_height(idx) / get_layer_width(idx) / get_neuron_count(idx)`
- `set_seed(seed: int)` or `seed_rng(seed: int)` on `Region` (or `Bus`)

------

## Example pybind11 binding (key ideas)

> Identifiers are descriptive; Python-visible names are **snake_case**; no 1–2 char variables.

```cpp
// src/cpp/bindings/grownet_pybind.cpp
#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <pybind11/stl.h>
namespace py = pybind11;

// ADAPT includes to your tree
#include "Region.h"

static void tick_2d_numpy(Region& region,
    py::array frame) {
    // Validate dtype and layout
    if (!(py::isinstance<py::array_t<float>>(frame) || py::isinstance<py::array_t<double>>(frame))) {
        throw std::invalid_argument("tick_2d expects float32 or float64 NumPy array");
    }
    if (frame.ndim() != 2) {
        throw std::invalid_argument("tick_2d expects a 2D array of shape (height, width)");
    }
    const int frame_height = static_cast<int>(frame.shape(0));
    const int frame_width  = static_cast<int>(frame.shape(1));

    // Get raw pointer (C-contiguous ensures stride[1] == sizeof(T))
    py::buffer_info buf = frame.request();
    // Release GIL during the heavy work
    py::gil_scoped_release release;

    // ADAPT: if your Region has setInputFrame + tick2D
    if (buf.itemsize == sizeof(float)) {
        auto* ptr = static_cast<float*>(buf.ptr);
        region.setInputFrame(/*input layer index?*/ 0, std::vector<float>(ptr, ptr + frame_height*frame_width),
                             frame_height, frame_width);
        region.tick2D(frame_height, frame_width);
    } else {
        // Convert double->float if your C++ expects float
        auto* dptr = static_cast<double*>(buf.ptr);
        std::vector<float> tmp(frame_height * frame_width);
        for (int index = 0; index < frame_height * frame_width; ++index) tmp[index] = static_cast<float>(dptr[index]);
        region.setInputFrame(0, tmp, frame_height, frame_width);
        region.tick2D(frame_height, frame_width);
    }
}

PYBIND11_MODULE(grownet_native, module) {
    module.doc() = "GrowNet Python bindings backed by the C++ core (deterministic, parity-aligned).";

    py::class_<Region, std::shared_ptr<Region>>(module, "Region")
        .def(py::init<const std::string&>(), py::arg("name"))
        .def("add_input_layer_2d",   &Region::addInputLayer2D,   py::arg("height"), py::arg("width"))
        .def("add_output_layer_2d",  &Region::addOutputLayer2D,  py::arg("height"), py::arg("width"), py::arg("bias") = 0.0f)
        .def("connect_layers_windowed",
             &Region::connectLayersWindowed,
             py::arg("src_index"), py::arg("dst_index"),
             py::arg("kernel_h"), py::arg("kernel_w"),
             py::arg("stride_h"), py::arg("stride_w"),
             py::arg("padding"),  py::arg("feedback"))
        .def("tick_2d", &tick_2d_numpy, py::arg("frame"))
        .def("has_edge", &Region::hasEdge,      // if available
             py::arg("src_layer"), py::arg("src_neuron"),
             py::arg("dst_layer"), py::arg("dst_neuron"))
        .def("connect_neurons", &Region::connectNeurons,  // if available
             py::arg("src_layer"), py::arg("src_neuron"),
             py::arg("dst_layer"), py::arg("dst_neuron"),
             py::arg("feedback") = false)
        .def("record_mesh_rule_for", &Region::recordMeshRuleFor, // if available
             py::arg("src_layer"), py::arg("dst_layer"),
             py::arg("probability") = 1.0, py::arg("feedback") = false)
        .def_property_readonly("bus", [](Region& region) {
            return &region.bus();      // return non-owning pointer / reference
        }, py::return_value_policy::reference);

    // Expose Bus with get_current_step (read-only)
    py::class_<LateralBus>(module, "LateralBus")
        .def("get_current_step", &LateralBus::get_current_step);
}
```

**Notes**

- Use `py::gil_scoped_release` around **tick and kernel calls**.
- Prefer `std::shared_ptr<T>` for objects that can live beyond a single call.
- If you have multiple input layers, expose and require an `input_layer_index` argument for `tick_2d` or bind `set_input_frame` separately.

------

## Python package surface (thin wrapper, snake_case)

```python
# src/python/grownet_native/__init__.py
from ._version import __version__  # optional
from .interop import ensure_frame_2d

from grownet_native import Region as _Region  # bound class from the extension

class Region:
    """Python-friendly wrapper around the C++ Region. Public API is snake_case."""
    def __init__(self, name: str):
        self._inner = _Region(name)

    def add_input_layer_2d(self, height: int, width: int) -> int:
        return self._inner.add_input_layer_2d(height, width)

    def add_output_layer_2d(self, height: int, width: int, bias: float = 0.0) -> int:
        return self._inner.add_output_layer_2d(height, width, bias)

    def connect_layers_windowed(self, src_index: int, dst_index: int,
                                kernel_h: int, kernel_w: int,
                                stride_h: int, stride_w: int,
                                padding: str = "same", feedback: bool = False) -> int:
        return self._inner.connect_layers_windowed(src_index, dst_index, kernel_h, kernel_w,
                                                   stride_h, stride_w, padding, feedback)

    def tick_2d(self, frame):
        frame = ensure_frame_2d(frame)  # dtype, contiguity checks
        return self._inner.tick_2d(frame)

    @property
    def bus(self):
        return self._inner.bus()
```

*(The wrapper class keeps public names in **snake_case** and lets you add simple validation without touching C++.)*

------

## Build system: `pyproject.toml` + `CMakeLists.txt`

**pyproject.toml**

```toml
[build-system]
requires = ["scikit-build-core>=0.5", "pybind11>=2.12", "numpy"]
build-backend = "scikit_build_core.build"

[project]
name = "grownet_native"
version = "0.1.0"
requires-python = ">=3.9"
dependencies = ["numpy>=1.22"]
description = "GrowNet Python bindings backed by the C++ core"
readme = "README.md"
license = { text = "Apache-2.0" }

[tool.scikit-build]
wheel.expand-macos-universal-tags = true
```

**CMakeLists.txt**

```cmake
cmake_minimum_required(VERSION 3.20)
project(grownet_native LANGUAGES CXX)

find_package(pybind11 REQUIRED CONFIG)
find_package(Python REQUIRED COMPONENTS Interpreter Development.Module)
# ADAPT: add your core include dirs and sources
add_library(grownet_core OBJECT
    src/cpp/core/Region.cpp
    src/cpp/core/Layer.cpp
    # ...
)
target_include_directories(grownet_core PUBLIC src/cpp/core/include)

pybind11_add_module(grownet_native MODULE
    src/cpp/bindings/grownet_pybind.cpp
)
target_link_libraries(grownet_native PRIVATE grownet_core)
target_compile_features(grownet_native PRIVATE cxx_std_17)
target_compile_definitions(grownet_native PRIVATE $<$<CONFIG:Release>:NDEBUG>)
if (MSVC)
  target_compile_options(grownet_native PRIVATE /O2 /permissive-)
else()
  target_compile_options(grownet_native PRIVATE -O3 -fvisibility=hidden)
endif()
```

------

## Determinism guardrails

- Expose a `seed_rng(seed: int)` or `set_seed` method in C++ or Region to ensure **identical runs** from Python.
- **No fallback RNG** inside bindings—if a probabilistic path is invoked without a seeded RNG, raise a clear error.
- Keep **iteration order** fixed (layer index, neuron index) on the C++ side.

------

## Testing & CI strategy

- **Golden parity tests** in Python that run both:
  - the pure Python reference (existing path), and
  - the bound C++ path,
     on the same frames and RNG seed; assert identical outputs for:
  - 2D slot selection (anchor and reuse),
  - windowed wiring (center indices + **unique source** count),
  - proximity spatial hash (candidate counts; with STEP mode you can avoid RNG in CI).
- **CIBW (cibuildwheel)** to build manylinux/macOS/Windows wheels in CI.

------

## Phased rollout

1. **Bind the hot kernels first**: windowed wiring + 2D slot selection (largest wins).
2. Add `tick_2d(frame)` path and bus step access.
3. Bind optional helpers for proximity policy (`has_edge`, `connect_neurons`, `record_mesh_rule_for`).
4. Keep the pure‑Python fallback import in place initially; once coverage is solid, flip the default to C++ with a flag to force Python if needed.

------

## FAQ

- **Do we have to rename C++ methods to snake_case?**
   No. Bindings can expose Pythonic names while mapping to the existing C++ method names; just keep the **public Python names snake_case**.
- **What about memory ownership?**
   Return `std::shared_ptr<T>` for long‑lived objects. Use `py::return_value_policy::reference` for internal references (e.g., `bus()`).
- **GIL safety?**
   Wrap heavy C++ calls with `py::gil_scoped_release`. If you parallelize inside C++, ensure determinism (fixed order/reduction).

------

### Bottom line

**Yes, it’s not only possible—it’s the recommended path**: reuse the C++ core, expose a clean Python surface with pybind11, and keep GrowNet’s style and determinism intact. If you’d like, I can turn the snippets above into a ready‑to‑build **zip with CMake + pyproject + a working minimal binding** wired to your current C++ headers.