From ea02d541751dee04068c45c9bc1c6b341641873f Mon Sep 17 00:00:00 2001
From: Shahin Saadati <shahins@google.com>
Date: Thu, 20 Aug 2026 09:24:48 -0700
Subject: [PATCH] Add the Kotlin tab for driving a long-running tool to
 completion

The call_reimbursement_tool group showed Python, TypeScript, Go and Java
but not Kotlin, even though the page already carries a Kotlin tab for
defining the tool a few sections earlier. Defining a long-running tool
without showing how to resume it leaves the Kotlin reader at the point
where the invocation pauses.

The new region extends the file that already backs this page rather than
adding a second one. It mirrors the Python flow: watch for the call whose
id appears in Event.longRunningToolIds, keep the matching
FunctionResponse, then send a copy of it back with the final status to
resume the paused invocation.

Scoped deliberately to that group. RequestInputTool and GetUserChoiceTool
were also on this backlog row, but they have no host page in ANY language
- they appear nowhere in the narrative docs, only in generated API
reference - so adding a Kotlin-only section for them would invent
structure rather than close a gap. Recorded for a product-docs request
instead.
---
 docs/tools-custom/function-tools.md           |  6 ++
 .../tools/function-tools/LongRunningTool.kt   | 56 +++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/docs/tools-custom/function-tools.md b/docs/tools-custom/function-tools.md
index 701fde8fe6..ea4f80afb5 100644
--- a/docs/tools-custom/function-tools.md
+++ b/docs/tools-custom/function-tools.md
@@ -679,6 +679,12 @@ it's None) into the content of the `FunctionResponse` sent back to the LLM.
     --8<-- "examples/java/snippets/src/main/java/tools/LongRunningFunctionExample.java:full_code"
     ```
 
+=== "Kotlin"
+
+    ```kotlin
+    --8<-- "examples/kotlin/snippets/tools/function-tools/LongRunningTool.kt:call_reimbursement_tool"
+    ```
+
 ??? "Python complete example: File Processing Simulation"
 
     ```python
diff --git a/examples/kotlin/snippets/tools/function-tools/LongRunningTool.kt b/examples/kotlin/snippets/tools/function-tools/LongRunningTool.kt
index b6260418be..2446eaceb3 100644
--- a/examples/kotlin/snippets/tools/function-tools/LongRunningTool.kt
+++ b/examples/kotlin/snippets/tools/function-tools/LongRunningTool.kt
@@ -4,7 +4,12 @@ import com.google.adk.kt.agents.Instruction
 import com.google.adk.kt.agents.LlmAgent
 import com.google.adk.kt.annotations.Param
 import com.google.adk.kt.annotations.Tool
+import com.google.adk.kt.events.Event
 import com.google.adk.kt.models.Gemini
+import com.google.adk.kt.runners.InMemoryRunner
+import com.google.adk.kt.types.Content
+import com.google.adk.kt.types.FunctionResponse
+import com.google.adk.kt.types.Part
 
 // --8<-- [start:long_running_tool]
 data class ReimbursementApproval(
@@ -47,3 +52,54 @@ fun main() {
         )
 }
 // --8<-- [end:long_running_tool]
+
+// --8<-- [start:call_reimbursement_tool]
+private fun printText(event: Event) {
+    val text = event.content?.parts?.mapNotNull { it.text }?.joinToString("").orEmpty()
+    if (text.isNotEmpty()) println("[${event.author}]: $text")
+}
+
+suspend fun callReimbursementAgent(
+    runner: InMemoryRunner,
+    userId: String,
+    sessionId: String,
+    query: String,
+) {
+    var pendingCallId: String? = null
+    var pendingResponse: FunctionResponse? = null
+
+    runner
+        .runAsync(
+            userId = userId,
+            sessionId = sessionId,
+            newMessage = Content(role = "user", parts = listOf(Part(text = query))),
+        ).collect { event ->
+            val callId = pendingCallId
+            if (callId == null) {
+                // A long-running call is the one whose id the event lists in longRunningToolIds.
+                pendingCallId =
+                    event
+                        .functionCalls()
+                        .firstOrNull { it.id != null && it.id in event.longRunningToolIds }
+                        ?.id
+            } else {
+                event
+                    .functionResponses()
+                    .firstOrNull { it.id == callId }
+                    ?.let { pendingResponse = it }
+            }
+            printText(event)
+        }
+
+    // The tool returned "pending" and the invocation paused. Resume it by sending the
+    // outcome back as a FunctionResponse carrying the same id.
+    val paused = pendingResponse ?: return
+    val updated = paused.copy(response = mapOf("status" to "approved"))
+    runner
+        .runAsync(
+            userId = userId,
+            sessionId = sessionId,
+            newMessage = Content(role = "user", parts = listOf(Part(functionResponse = updated))),
+        ).collect(::printText)
+}
+// --8<-- [end:call_reimbursement_tool]