Add Slack DM toggle for channel thread @-mentions

Opt-in setting (default off) in the Slack settings section, gated behind the project-bluebird flag. Reads/writes the new /api/code/user_settings/ endpoint; delivery itself is backend-driven via the team's Slack integration (PostHog/posthog#72087).

Generated-By: PostHog Code
Task-Id: 69e0939c-e6e1-4efa-9d5e-771b88f03b5a

Author: adboio

packages/api-client/src/posthog-client.ts

@@ -55,6 +55,7 @@ import type {
   ChannelFeedMessage,
   ChannelFeedMessageEvent,
   CodeReferenceArtefact,
+  CodeUserNotificationSettings,
   CommitArtefact,
   CommitDiffResponse,
   DismissalArtefact,
@@ -4112,6 +4113,47 @@ export class PostHogAPIClient {
     return (await response.json()) as SignalUserAutonomyConfig;
   }
 
+  async getCodeUserNotificationSettings(): Promise<CodeUserNotificationSettings> {
+    const url = new URL(`${this.api.baseUrl}/api/code/user_settings/`);
+    const path = "/api/code/user_settings/";
+
+    const response = await this.api.fetcher.fetch({
+      method: "get",
+      url,
+      path,
+    });
+
+    if (!response.ok) {
+      throw new Error(
+        `Failed to fetch Code notification settings: ${response.statusText}`,
+      );
+    }
+    return (await response.json()) as CodeUserNotificationSettings;
+  }
+
+  async updateCodeUserNotificationSettings(updates: {
+    slack_mention_notifications: boolean;
+  }): Promise<CodeUserNotificationSettings> {
+    const url = new URL(`${this.api.baseUrl}/api/code/user_settings/`);
+    const path = "/api/code/user_settings/";
+
+    const response = await this.api.fetcher.fetch({
+      method: "post",
+      url,
+      path,
+      overrides: {
+        body: JSON.stringify(updates),
+      },
+    });
+
+    if (!response.ok) {
+      throw new Error(
+        `Failed to update Code notification settings: ${response.statusText}`,
+      );
+    }
+    return (await response.json()) as CodeUserNotificationSettings;
+  }
+
   async getSlackChannelsForIntegration(
     integrationId: number,
     params?: SlackChannelsQueryParams,

packages/shared/src/domain-types.ts

@@ -796,6 +796,12 @@ export interface SignalUserAutonomyConfig {
   updated_at?: string;
 }
 
+/** Per-user PostHog Code notification preferences, served by `/api/code/user_settings/`. */
+export interface CodeUserNotificationSettings {
+  /** Send a Slack DM when someone @-mentions the user in a channel thread. Opt-in. */
+  slack_mention_notifications: boolean;
+}
+
 export interface SlackChannelOption {
   id: string;
   name: string;

packages/ui/src/features/settings/sections/SlackMentionNotificationsSettings.tsx

@@ -0,0 +1,65 @@
+import { ANALYTICS_EVENTS, PROJECT_BLUEBIRD_FLAG } from "@posthog/shared";
+import { useFeatureFlag } from "@posthog/ui/features/feature-flags/useFeatureFlag";
+import { useIntegrationSelectors } from "@posthog/ui/features/integrations/store";
+import {
+  useCodeUserNotificationSettings,
+  useCodeUserNotificationSettingsMutations,
+} from "@posthog/ui/features/settings/sections/useCodeUserNotificationSettings";
+import { track } from "@posthog/ui/shell/analytics";
+import { Flex, Switch, Text } from "@radix-ui/themes";
+
+/**
+ * Opt-in Slack DMs for channel-thread @-mentions. The preference lives on the
+ * PostHog backend (per user, across projects); delivery uses the team's Slack
+ * integration, so the section only shows once a workspace is connected.
+ */
+export function SlackMentionNotificationsSettings() {
+  // Channel threads (and their @-mentions) only exist behind the bluebird flag.
+  const channelsEnabled = useFeatureFlag(
+    PROJECT_BLUEBIRD_FLAG,
+    import.meta.env.DEV,
+  );
+  const { hasSlackIntegration } = useIntegrationSelectors();
+  const { data: settings, isLoading } = useCodeUserNotificationSettings();
+  const { handleUpdateSlackMentionNotifications } =
+    useCodeUserNotificationSettingsMutations();
+
+  // The connect-workspace prompt is the parent section's job.
+  if (!channelsEnabled || !hasSlackIntegration) return null;
+
+  const enabled = settings?.slack_mention_notifications ?? false;
+
+  const onCheckedChange = (checked: boolean) => {
+    track(ANALYTICS_EVENTS.SETTING_CHANGED, {
+      setting_name: "slack_mention_notifications",
+      new_value: checked,
+      old_value: enabled,
+    });
+    void handleUpdateSlackMentionNotifications(checked);
+  };
+
+  return (
+    <Flex
+      direction="column"
+      gap="2"
+      className="border-(--gray-5) border-t border-dashed pt-4"
+    >
+      <Flex align="center" justify="between" gap="3">
+        <Flex direction="column" gap="1">
+          <Text className="font-medium text-(--gray-12) text-sm">
+            Mention notifications
+          </Text>
+          <Text className="text-(--gray-11) text-[13px]">
+            Get a Slack DM when someone @-mentions you in a channel thread.
+          </Text>
+        </Flex>
+        <Switch
+          checked={enabled}
+          disabled={isLoading}
+          onCheckedChange={onCheckedChange}
+          aria-label="Slack DM on @-mention"
+        />
+      </Flex>
+    </Flex>
+  );
+}

packages/ui/src/features/settings/sections/SlackSettings.tsx

@@ -5,6 +5,7 @@ import { openUrlInBrowser } from "@posthog/ui/utils/browser";
 import { getPostHogUrl } from "@posthog/ui/utils/urls";
 import { Button, Flex, Text, Tooltip } from "@radix-ui/themes";
 import { SlackInboxNotificationsSettings } from "./SlackInboxNotificationsSettings";
+import { SlackMentionNotificationsSettings } from "./SlackMentionNotificationsSettings";
 
 export function SlackSettings() {
   const projectId = useAuthStateValue((s) => s.currentProjectId);
@@ -52,6 +53,8 @@ export function SlackSettings() {
         isLoading={isLoading}
         showHeader={false}
       />
+
+      <SlackMentionNotificationsSettings />
     </Flex>
   );
 }

packages/ui/src/features/settings/sections/useCodeUserNotificationSettings.ts

@@ -0,0 +1,56 @@
+import type { CodeUserNotificationSettings } from "@posthog/shared/domain-types";
+import { useOptionalAuthenticatedClient } from "@posthog/ui/features/auth/authClient";
+import { useAuthenticatedQuery } from "@posthog/ui/hooks/useAuthenticatedQuery";
+import { toast } from "@posthog/ui/primitives/toast";
+import { useQueryClient } from "@tanstack/react-query";
+import { useCallback } from "react";
+
+const CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY = [
+  "code-user-notification-settings",
+] as const;
+
+/** The user's PostHog Code notification settings (all-defaults until first saved). */
+export function useCodeUserNotificationSettings() {
+  return useAuthenticatedQuery(CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY, (client) =>
+    client.getCodeUserNotificationSettings(),
+  );
+}
+
+/** Mutations for the settings above; reads come from `useCodeUserNotificationSettings`. */
+export function useCodeUserNotificationSettingsMutations() {
+  const client = useOptionalAuthenticatedClient();
+  const queryClient = useQueryClient();
+
+  const handleUpdateSlackMentionNotifications = useCallback(
+    async (enabled: boolean) => {
+      if (!client) return;
+      const previous = queryClient.getQueryData<CodeUserNotificationSettings>(
+        CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY,
+      );
+      // Optimistic: the switch reflects the new state immediately, reverted on failure.
+      queryClient.setQueryData<CodeUserNotificationSettings>(
+        CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY,
+        { slack_mention_notifications: enabled },
+      );
+      try {
+        const fresh = await client.updateCodeUserNotificationSettings({
+          slack_mention_notifications: enabled,
+        });
+        queryClient.setQueryData(CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY, fresh);
+      } catch (error: unknown) {
+        queryClient.setQueryData(
+          CODE_USER_NOTIFICATION_SETTINGS_QUERY_KEY,
+          previous,
+        );
+        const message =
+          error instanceof Error
+            ? error.message
+            : "Failed to update mention notifications";
+        toast.error(message);
+      }
+    },
+    [client, queryClient],
+  );
+
+  return { handleUpdateSlackMentionNotifications };
+}