# Core configuration (/docs/api-reference/core-configuration)



Core configuration separates describing an object graph from constructing expensive model objects. `LazyCall(target)(...)` records a target plus named arguments in an editable OmegaConf node; `instantiate` walks the graph and creates the objects only when the runtime is ready.

This package requires `attrs` and `omegaconf` (provided by the video/model runtime environments, not the minimal CLI install).

## Deferred construction example [#deferred-construction-example]

```python
from torch import nn

from worldfoundry.core.configuration import LazyCall, instantiate

Linear = LazyCall(nn.Linear)
layer_config = Linear(in_features=8, out_features=4, bias=False)

# Config composition can still change the graph without a live module.
layer_config.out_features = 6
layer = instantiate(layer_config)

assert isinstance(layer, nn.Linear)
assert layer.in_features == 8
assert layer.out_features == 6
```

`LazyCall` accepts keyword arguments only. Defaults from the target signature are recorded before explicit values are applied. Nested lists and mappings are instantiated recursively unless a config sets `_recursive_=False`; unknown mappings and primitive values pass through unchanged.

## Structured released-model config [#structured-released-model-config]

`Config` and its nested attrs classes hold the small, shared part of released inference configuration: the deferred model graph, checkpoint source, runtime/CuDNN settings, model-parallel settings, and job identity. Model-specific fields remain in the model's own lazy graph.

`make_freezable` adds a recursive `freeze()` operation to attrs classes declared with `slots=False`. Freezing is a runtime guard against accidental mutation after composition; it does not make referenced PyTorch modules immutable.

## Complete reference [#complete-reference]

The blocks below are the generated signatures for this category. Use the on-page symbol index to jump; source links open the defining implementation behind each lazy export.

<PythonApiGroupReference group="core-configuration" />