Errors and Omissions (E&O) insurance protects your company from claims if your client sues you for errors or the failure of your work to perform as laid out in your contract.
E&O insurance covers legal expenses, even for the most unjustifiable claims. E&O will pay for any judgments against you including any court costs, up to the coverage limits on your policy.
This is a separate policy and general liability excludes coverage from claims related to the delivery of professional services.