Here is the small tip for all WordPress users , those who want to add Post/Article title in meta description of all the posts .This trick is helpful in case if your posts indicating duplicate meta description error in Google webmaster tool.
How to insert Post title in meta description?
First of all install this Plugin All in One SEO Pack in your WordPress blog.
Now go to All in One Seo > General settings > Look for Title setting it will look like this
In “Description Format” Tab replace the code %description% with this one
See the screen shot
You have done adding Title Tag before description of all posts.