
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
Given that the function $f(x) = \sin(2x + \varphi + \frac{π}{3})$ ($|\varphi| < \frac{π}{2}$) has a local maximum at $x = \frac{π}{6}$, and $f(x)$ is monotonically increasing on the interval $[-a, a]$ ($a > 0$), determine the maximum value of $a$.

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