
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
In $\triangle ABC$, the lengths of the sides opposite to angles $A$, $B$, and $C$ are $a$, $b$, and $c$ respectively. Given vectors $\overrightarrow{m}=(1,2\sin A)$ and $\overrightarrow{n}=(\sin A,1+\cos A)$ satisfy $\overrightarrow{m}\parallel \overrightarrow{n}$, and $b+c= \sqrt {3}a$.  
(I) Find the magnitude of angle $A$;  
(II) Find the value of $\sin \left(B+ \frac {\pi}{6}\right)$.

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