Outlook add-in -> Context add-in Manifest

Question

I'm trying to create an Outlook add-in that activates in every email. I wanna know if there's way to call a function execution like that. I just need to have access to the email text as soon as the user goes to see the email. Is for fraud detection with AI.

I found this manifest of Microsoft:

 <?xml version="1.0" encoding="UTF-8"?>
<OfficeApp
          xmlns="http://schemas.microsoft.com/office/appforoffice/1.1"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xmlns:bt="http://schemas.microsoft.com/office/officeappbasictypes/1.0"
          xmlns:mailappor="http://schemas.microsoft.com/office/mailappversionoverrides/1.0"
          xsi:type="MailApp">

  <!-- Begin Basic Settings: Add-in metadata, used for all versions of Office unless override provided. -->

  <!-- IMPORTANT! Id must be unique for your add-in, if you reuse this manifest ensure that you change this id to a new GUID. -->
  <Id>351bf5d8-c3e5-4c35-8f0b-3da9a28f22f2</Id>

  <!-- Version. Updates from the store only get triggered if there is a version change. -->
  <Version>1.0.0.0</Version>
  <ProviderName>Outlook Dev Center</ProviderName>
  <DefaultLocale>en-US</DefaultLocale>
  <!-- The display name of your add-in. Used on the store and various places of the Office UI such as the add-ins dialog. -->
  <DisplayName DefaultValue="Contoso Order Number Add-in" />
  <Description DefaultValue="A sample add-in that demonstrates contextual activation on a Regex match."/>

  <!-- Icon for your add-in. Used on installation screens and the add-ins dialog. -->
  <IconUrl DefaultValue="https://127.0.0.1:8080/assets/icon-32.png" />
  <HighResolutionIconUrl DefaultValue="https://127.0.0.1:8080/assets/hi-res-icon.png"/>
  <!-- End Basic Settings. -->

  <!-- Legacy settings -->
  <!-- These values will be used for legacy clients that do not understand the -->
  <!-- VersionOverrides schema. These values will be ignored by clients that do -->
  <!-- understand VersionOverrides, with the exception of Permissions -->
  <Hosts>
    <Host Name="Mailbox" />
  </Hosts>
  <Requirements>
    <Sets>
      <Set Name="Mailbox" MinVersion="1.1" />
    </Sets>
  </Requirements>
  <FormSettings>
    <Form xsi:type="ItemRead">
      <DesktopSettings>
        <SourceLocation DefaultValue="https://127.0.0.1:8080/index.html"/>
        <RequestedHeight>250</RequestedHeight>
      </DesktopSettings>
    </Form>
  </FormSettings>

  <Permissions>ReadWriteItem</Permissions>
  <!-- Note that this Rule element matches the Rule element inside the -->
  <!-- DetectedEntity element below. This is so that older clients will be able -->
  <!-- to activate the add-in on the same context. -->
  <Rule xsi:type="RuleCollection" Mode="And">
    <Rule xsi:type="ItemIs" ItemType="Message" FormType="Read" />
    <Rule xsi:type="ItemHasRegularExpressionMatch" RegExName="9Digits" RegExValue="\d{9}" PropertyName="BodyAsPlaintext"/>
  </Rule>
  <DisableEntityHighlighting>false</DisableEntityHighlighting>

  <VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
    <!-- VersionOverrides for the v1.1 schema -->
    <VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
      <Requirements>
        <bt:Sets DefaultMinVersion="1.5">
          <bt:Set Name="Mailbox" />
        </bt:Sets>
      </Requirements>
      <Hosts>
        <Host xsi:type="MailHost">

          <DesktopFormFactor>
            <!-- DetectedEntity -->
            <ExtensionPoint xsi:type="DetectedEntity">
              <Label resid="contextLabel" />
              <SourceLocation resid="detectedEntityURL" />
              <Rule xsi:type="RuleCollection" Mode="And">
                <Rule xsi:type="ItemIs" ItemType="Message" />
                <Rule xsi:type="ItemHasRegularExpressionMatch" RegExName="OrderNumber" RegExValue="CO-\d{9}" PropertyName="BodyAsPlaintext"/>
              </Rule>
            </ExtensionPoint>
          </DesktopFormFactor>
        </Host>
      </Hosts>

      <Resources>
        <bt:Images>
          <bt:Image id="icon16" DefaultValue="https://127.0.0.1:8080/assets/icon-16.png"/>
          <bt:Image id="icon32" DefaultValue="https://127.0.0.1:8080/assets/icon-32.png"/>
          <bt:Image id="icon80" DefaultValue="https://127.0.0.1:8080/assets/icon-80.png"/>
        </bt:Images>
        <bt:Urls>
          <bt:Url id="detectedEntityURL" DefaultValue="https://127.0.0.1:8080/index.html"/>
        </bt:Urls>
        <bt:ShortStrings>
          <bt:String id="contextLabel" DefaultValue="Order Number Detected"/>
        </bt:ShortStrings>
      </Resources>
    </VersionOverrides>
  </VersionOverrides>
</OfficeApp>

The issue is only activating with regex.

Answer 1

There is a way for Compose add-ins to run automatically based on certain events in requirement set 1.10, but there isn't a similar feature for Read add-ins.

Contextual add-ins still require interaction from the user to launch the add-in.

A user could pin a task pane add-in, and it would launch automatically, but this requires an action from the user, and the add-in would always be visible.

For part of the scenario you described, you want to get the text of the email. This could be possible from a backend service using change notifications in Microsoft Graph, which could notify the service whenever a user receives an email. Though, this would trigger on every message, not just messages read by the user.