refactor(telemetry): extract embedded agent posthog config builder

packages/common/embedded-agent-browser.test.ts

@@ -1,6 +1,10 @@
+import type { CaptureResult } from 'posthog-js'
 import { describe, expect, it } from 'vitest'
 
-import { detectEmbeddedAgentBrowser } from './embedded-agent-browser'
+import {
+  buildEmbeddedAgentBrowserConfig,
+  detectEmbeddedAgentBrowser,
+} from './embedded-agent-browser'
 
 describe('detectEmbeddedAgentBrowser', () => {
   it('detects Claude Desktop on Mac with Electron token', () => {
@@ -71,3 +75,43 @@ describe('detectEmbeddedAgentBrowser', () => {
     expect(detectEmbeddedAgentBrowser('')).toBeUndefined()
   })
 })
+
+describe('buildEmbeddedAgentBrowserConfig', () => {
+  const claudeUserAgent =
+    'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Claude/1.37937.3 Chrome/148.0.7778.280 Safari/537.36 MSIX'
+
+  it('returns an empty config for non-agent user agents', () => {
+    expect(
+      buildEmbeddedAgentBrowserConfig(
+        'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/148.0.0.0 Safari/537.36'
+      )
+    ).toEqual({})
+  })
+
+  it('returns an empty config when the user agent is unavailable', () => {
+    expect(buildEmbeddedAgentBrowserConfig(undefined)).toEqual({})
+  })
+
+  it('annotates captured events with the detected agent browser', () => {
+    const config = buildEmbeddedAgentBrowserConfig(claudeUserAgent)
+    const beforeSend = config.before_send as (cr: CaptureResult | null) => CaptureResult | null
+
+    const result = beforeSend({
+      uuid: '00000000-0000-0000-0000-000000000000',
+      event: '$pageview',
+      properties: { $current_url: 'https://supabase.com/dashboard/projects' },
+    } as CaptureResult)
+
+    expect(result?.properties).toEqual({
+      $current_url: 'https://supabase.com/dashboard/projects',
+      embedded_agent_browser: 'claude_desktop',
+    })
+  })
+
+  it('passes through null capture results', () => {
+    const config = buildEmbeddedAgentBrowserConfig(claudeUserAgent)
+    const beforeSend = config.before_send as (cr: CaptureResult | null) => CaptureResult | null
+
+    expect(beforeSend(null)).toBeNull()
+  })
+})

packages/common/embedded-agent-browser.ts

@@ -1,11 +1,12 @@
+import type { PostHogConfig } from 'posthog-js'
+
 export type EmbeddedAgentBrowser = 'claude_desktop' | 'chatgpt_desktop'
 
 const CLAUDE_DESKTOP_UA = /(^| )Claude\/\d/
 const CHATGPT_DESKTOP_UA = /(^| )ChatGPT\/\d/
 
-// Claude Desktop >= ~1.37937 drops the Electron/ UA token on every platform, so Claude
-// matches on its product token alone. ChatGPT's token also appears in mobile in-app
-// WebView UAs (human browsing), so it stays gated on the Electron/ token.
+// Newer Claude Desktop builds omit the Electron/ token, so Claude matches on its product
+// token alone. ChatGPT's token also appears in mobile in-app WebViews, so it stays Electron-gated.
 export function detectEmbeddedAgentBrowser(userAgent: string): EmbeddedAgentBrowser | undefined {
   if (CLAUDE_DESKTOP_UA.test(userAgent)) return 'claude_desktop'
   if (CHATGPT_DESKTOP_UA.test(userAgent) && userAgent.includes('Electron/')) {
@@ -13,3 +14,21 @@ export function detectEmbeddedAgentBrowser(userAgent: string): EmbeddedAgentBrow
   }
   return undefined
 }
+
+export function buildEmbeddedAgentBrowserConfig(
+  userAgent: string | undefined
+): Partial<PostHogConfig> {
+  const embeddedAgentBrowser = userAgent ? detectEmbeddedAgentBrowser(userAgent) : undefined
+  if (!embeddedAgentBrowser) return {}
+
+  return {
+    before_send: (captureResult) => {
+      if (!captureResult) return captureResult
+      captureResult.properties = {
+        ...captureResult.properties,
+        embedded_agent_browser: embeddedAgentBrowser,
+      }
+      return captureResult
+    },
+  }
+}

packages/common/posthog-client.ts

@@ -4,7 +4,7 @@ import posthog, {
   type SessionRecordingOptions,
 } from 'posthog-js'
 
-import { detectEmbeddedAgentBrowser } from './embedded-agent-browser'
+import { buildEmbeddedAgentBrowserConfig } from './embedded-agent-browser'
 import { safeSessionStorage } from './safe-storage'
 
 export type { CapturedNetworkRequest, SessionRecordingOptions }
@@ -89,27 +89,15 @@ class PostHogClient {
       return
     }
 
-    const embeddedAgentBrowser =
-      typeof navigator !== 'undefined' ? detectEmbeddedAgentBrowser(navigator.userAgent) : undefined
-
     const config: Partial<PostHogConfig> = {
       api_host: this.config.apiHost,
       ui_host: this.config.uiHost,
       autocapture: false, // We'll manually track events
       capture_pageview: false, // We'll manually track pageviews
       capture_pageleave: false, // We'll manually track page leaves
-      ...(embeddedAgentBrowser && {
-        before_send: (captureResult) => {
-          if (!captureResult) return captureResult
-          return {
-            ...captureResult,
-            properties: {
-              ...captureResult.properties,
-              embedded_agent_browser: embeddedAgentBrowser,
-            },
-          }
-        },
-      }),
+      ...buildEmbeddedAgentBrowserConfig(
+        typeof navigator !== 'undefined' ? navigator.userAgent : undefined
+      ),
       ...buildSessionRecordingConfig(sessionReplay),
       loaded: (posthog) => {
         // Apply pending properties that were set before PostHog