
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 length of the chord cut by the circle $x^2+y^2=4$ on the line 
$$
\begin{cases}
x=2- \frac{1}{2}t \\
y=-1+ \frac{1}{2}t
\end{cases}
$$
(with $t$ as the parameter) is _____________.

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