keras-team/keras · error · ValueError

Inputs to a layer should be tensors. Got '{x}' (of type {typ

Error message

Inputs to a layer should be tensors. Got '{x}' (of type {type(x)}) as input for layer '{layer_name}'.

What it means

Error "Inputs to a layer should be tensors. Got '{x}' (of type {type(x)}) as input for layer '{layer_name}'." thrown in keras-team/keras.

Source

Thrown at keras/src/layers/input_spec.py:188

                + "})`."
            )
        raise ValueError(
            f'Layer "{layer_name}" expects {len(input_spec)} input(s),'
            f" but it received {len(inputs)} input tensors. "
            f"Inputs received: {inputs}"
        )
    for input_index, (x, spec) in enumerate(zip(inputs, input_spec)):
        if spec is None:
            continue
        if x is None and spec.optional:
            continue

        # Having a shape/dtype is the only commonality of the various
        # tensor-like objects that may be passed. The most common kind of
        # invalid type we are guarding for is a Layer instance (Functional API),
        # which does not have a `shape` attribute.
        if not hasattr(x, "shape"):
            raise ValueError(
                f"Inputs to a layer should be tensors. Got '{x}' "
                f"(of type {type(x)}) as input for layer '{layer_name}'."
            )

        shape = backend.standardize_shape(x.shape)
        ndim = len(shape)
        # Check ndim.
        if spec.ndim is not None and not spec.allow_last_axis_squeeze:
            if ndim != spec.ndim:
                raise ValueError(
                    f"Input {input_index} with name '{spec.name}' of layer "
                    f"'{layer_name}' is incompatible with the layer: "
                    f"expected ndim={spec.ndim}, found ndim={ndim}. "
                    f"Full shape received: {shape}"
                )
        if spec.max_ndim is not None:
            if ndim is not None and ndim > spec.max_ndim:
                raise ValueError(

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/layers/input_spec.py:188 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/4bdd7e9219735af0. Report an issue: GitHub.