
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
The function $y = f(x)$ has a graph on which two distinct points $A(x_1, y_1)$ and $B(x_2, y_2)$ have tangent slopes of $k_A$ and $k_B$, respectively. The "square curvature" between points A and B on the curve $y = f(x)$ is defined as $\phi(A, B) = \frac {|k_{A}-k_{B}|}{|AB|^2}$. Suppose on the curve $y = e^x + x$, two distinct points $A(x_1, y_1)$ and $B(x_2, y_2)$ exist such that $x_1 - x_2 = 1$, then the range of $\phi(A, B)$ is _______.

Present the answer in LaTex format: \boxed{Your answer}
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