I want to limit the size of my page description to crawler

[ymcus]

dear sir,
I want to limit the size of my page description to crawler, i want a plugin or integration code to reduce to description size of my content upto 150 when crawler crawl my site e.g:-
<description=I want to limit the size of my page description to crawler, i want a plugin or integration code to reduce/>
and full content under
<blockquote class="postcontent restore ">
I want to limit the size of my page description to crawler, i want a plugin or integration code to reduce to description size of my content upto 150 when crawler crawl my site
/>