Use descriptors to boost signal of word list

You can add features to your LUIS app to improve its accuracy. Features help LUIS by providing hints that certain words and phrases are part of an app domain vocabulary.

A descriptor (phrase list) includes a group of values (words or phrases) that belong to the same class and must be treated similarly (for example, names of cities or products). What LUIS learns about one of them is automatically applied to the others as well. This list is not the same thing as a list entity (exact text matches) of matched words.

A descriptor adds to the vocabulary of the app domain as a second signal to LUIS about those words.

Review feature concepts to understand when and why to use a descriptor.


This document uses the preview LUIS portal.

Add descriptor

  1. Open your app by clicking its name on My Apps page, and then click Build, then click Descriptors in your app's left panel.

  2. On the Descriptors page, click + Add Descriptor.

  3. In the Create new phrase list descriptor dialog box, enter a name such as Cities for the descriptor. In the Value box, type the values of the descriptors, such as Seattle. You can type one value at a time, or a set of values separated by commas, and then press Enter.

    Add descriptor Cities

    Once you have entered enough values for LUIS, suggestions appear. You can + Add all of the proposed values, or select individual terms.

  4. Keep These values are interchangeable checked if the added descriptor values are alternatives that can be used interchangeably.

  5. Select Done. The new descriptor is added to the Descriptors page.


You can delete, or deactivate a descriptor from the contextual toolbar on the Descriptors page.

Next steps

After adding, editing, deleting, or deactivating a descriptor, train and test the app again to see if performance improves.