Context is a Search API query parameter that can be used to include custom data in a query. It can be leveraged in Coveo query pipeline conditions and can also provide Coveo Machine Learning (Coveo ML) models with specific contextual information about the current query so they can output more personalized suggestions.

When context data is included in a query, the custom data field of the corresponding Search usage analytics event is typically populated with equivalent information to allow Coveo ML models to learn from that logged data.