Git: show more context when using git add -i or git add -e?

Short answer: no.

git diff has the -U<n> option which allows you to customize the number of lines to show around a change. For example, git diff -U5 ... will show 5 lines of context. As far as I can tell, there is no such option available for the diff display in the interactive mode.

To confirm, this is still not possible in 2019.

An external tool like jjlee/git-meld-index can help:

git-meld-index runs meld -- or any other git difftool (kdiff3, diffuse, etc.) -- to allow you to interactively stage changes to the git index (also known as the git staging area).

This is similar to the functionality of git add -p, and git add --interactive.

In some cases meld is easier / quicker to use than git add -p or the staging feature in tools like git gui.
That's because meld allows you, for example, to:

• see more context,
• see intra-line diffs
• edit by hand and see 'live' diff updates (updated after every keypress)
• navigate to a change without saying 'n' to every change you want to skip