3.8.3.9 -agent and -noagent: control use of Pageant for authentication
The -agent option turns on SSH authentication using Pageant, and -noagent turns it off. These options are only meaningful if you are using SSH.
See chapter 9 for general information on Pageant.
These options are equivalent to the agent authentication checkbox in the Auth panel of the PuTTY configuration box (see section 4.22.3).