This appears to be due to a change in the editor API. I've bisected the bug to agda/agda#8158. Specifically commit 3d7c2bbf, which states

Actual interaction in an editor should not be affected since it always
supplies a range with a goal command; only the testsuite provides no
ranges.

well, unfortunately it seems it affects us 😅

After this commit :CornelisGive returns the error Error in $: key "str" not found and fails to give.