> ## Documentation Index
> Fetch the complete documentation index at: https://docs.uniac.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Exceptions

> Exception types raised by the Uniac SDK.

## `uniac.LoadError`

Extends `RuntimeError`. Raised by [`load`](/sdk/load) when:

* `spec_cls` is not a class, or not a `NodeSpec` subclass.
* An `__init__` parameter has no env var and no default.
* An init parameter's annotated type is unsupported (anything other than `str | int | float | bool`).
* Env-var coercion fails (e.g., `"abc"` for an `int` parameter).

## `uniac.reader.spec.UniacValidationError`

Extends `Exception`. Raised by `NodeSpec._uniac_validate()` (see [`NodeSpec`](/sdk/nodespec)) when an annotated [`Node`](/sdk/node) slot is unset or holds the wrong type.

Both are raised during `load()` and signal wiring or configuration bugs that should fail loudly at startup rather than at first request.