docs(android): add Compose effect guidance

docs/platforms/android/integrations/jetpack-compose/index.mdx

@@ -356,3 +356,39 @@ SentryAndroid.init(this) { options ->
   })
 }
 ```
+
+## Custom Telemetry in Compose
+
+Composable functions can run many times during recomposition. Don't send custom Sentry spans, messages,
+breadcrumbs, or other telemetry directly from a composable body, as it can duplicate telemetry or attach it
+to the wrong UI lifecycle moment.
+
+Instead, send telemetry from:
+
+- `LaunchedEffect`, `DisposableEffect`, or `SideEffect` (more info in [Google's developer docs](https://developer.android.com/develop/ui/compose/side-effects))
+- Event callbacks such as `onClick` when the telemetry corresponds to a user action
+- APIs that run after composition, such as draw-time or layout-time lambdas, when that timing is what you want to measure
+
+For example, avoid capturing a message directly from the body:
+
+```kotlin
+@Composable
+fun LoginScreen() {
+  Sentry.captureMessage("Login screen shown")
+  // ...
+}
+```
+
+Instead, capture state in the body as needed but send it from an Effect API:
+
+```kotlin
+@Composable
+fun LoginScreen() {
+  val firstComposedAt = remember { Instant.now() }
+
+  LaunchedEffect(Unit) {
+    Sentry.captureMessage("Login screen shown: $firstComposedAt")
+  }
+  // ...
+}
+```

docs/platforms/android/tracing/instrumentation/custom-instrumentation.mdx

@@ -14,6 +14,14 @@ To capture transactions and spans customized to your organization's needs, you m
 
 <PlatformContent includePath="performance/enable-manual-instrumentation" />
 
+<Alert level="info" title="Using custom instrumentation in Jetpack Compose?">
+
+If you send custom Sentry spans or other telemetry from Jetpack Compose code, use Compose Effect APIs such as
+`LaunchedEffect`, `DisposableEffect`, or `SideEffect` instead of sending from a composable body. Composable bodies
+can run repeatedly during recomposition. See <PlatformLink to="/integrations/jetpack-compose/#custom-telemetry-in-compose">Jetpack Compose</PlatformLink>.
+
+</Alert>
+
 <PlatformContent includePath="performance/add-spans-example" />
 
 <PlatformContent includePath="performance/create-transaction-bound-to-scope" />