Use the figure of the first quadrant of the unit circle to find the exact circular function value.
\[
\tan 0
\]
The exact circular function value of \(\tan 0\) is \(\boxed{0}\).
Step 1 :The tangent of an angle in the unit circle is defined as the ratio of the y-coordinate to the x-coordinate of the point where the terminal side of the angle intersects the unit circle.
Step 2 :For an angle of 0 degrees, this point is (1,0).
Step 3 :Therefore, the tangent of 0 degrees is 0/1 = 0.
Step 4 :The exact circular function value of \(\tan 0\) is \(\boxed{0}\).