I\'m developing an extension for VSCode which is supplying completion items but there are word suggestions among them.
I know you can in your User/Workspace settings
Yes, extensions can change the default value of settings by contributing configurationDefaults in package.json:
configurationDefaults
package.json
"contributes": { "configurationDefaults": { "[lang]": { "editor.wordBasedSuggestions": false } } }
Where lang is the ID of the language in question.
lang