A group-based communication platform is configured to initialize processing actions executable via validated external resources. Moreover, the group-based communication platform may recommend specific processing actions to a user based at least in part on the user's activity in interacting with the group-based communication platform (e.g., via a client device), wherein such activity may be represented as environmental contextual data. Moreover, once the user selects a particular processing action for execution, the group-based communication retrieves at least a portion of the generated environmental contextual data to be passed to the validated external resource for use in executing the selected processing action.