From f63d402e0da324dbaf543172f5962364b09dc563 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 19 Jan 2026 18:53:52 +0000
Subject: [PATCH 1/2] Initial plan


From 2337ee46fc79c4e7c977604c6d1da8f492689d09 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 19 Jan 2026 18:59:08 +0000
Subject: [PATCH 2/2] Set ToolCallId from FunctionResultContent.CallId when
 creating tool messages

Co-authored-by: kzu <169707+kzu@users.noreply.github.com>
---
 src/xAI.Tests/ChatClientTests.cs | 77 ++++++++++++++++++++++++++++++++
 src/xAI/GrokChatClient.cs        |  7 ++-
 2 files changed, 82 insertions(+), 2 deletions(-)

diff --git a/src/xAI.Tests/ChatClientTests.cs b/src/xAI.Tests/ChatClientTests.cs
index 3e537cf..12b0142 100644
--- a/src/xAI.Tests/ChatClientTests.cs
+++ b/src/xAI.Tests/ChatClientTests.cs
@@ -2,6 +2,7 @@
 using System.Text.Json.Nodes;
 using Azure;
 using Devlooped.Extensions.AI;
+using Grpc.Core;
 using Microsoft.Extensions.AI;
 using Moq;
 using Tests.Client.Helpers;
@@ -520,5 +521,81 @@ public async Task AskFiles()
 
     }
 
+    [Fact]
+    public async Task GrokSetsToolCallIdFromFunctionResultContent()
+    {
+        GetCompletionsRequest? capturedRequest = null;
+        var client = new Mock<xAI.Protocol.Chat.ChatClient>(MockBehavior.Strict);
+        client.Setup(x => x.GetCompletionAsync(It.IsAny<GetCompletionsRequest>(), null, null, CancellationToken.None))
+            .Callback<GetCompletionsRequest, Metadata?, DateTime?, CancellationToken>((req, _, _, _) => capturedRequest = req)
+            .Returns(CallHelpers.CreateAsyncUnaryCall(new GetChatCompletionResponse
+            {
+                Outputs =
+                {
+                    new CompletionOutput
+                    {
+                        Message = new CompletionMessage
+                        {
+                            Content = "Done"
+                        }
+                    }
+                }
+            }));
+
+        var grok = new GrokChatClient(client.Object, "grok-4-1-fast");
+        var messages = new List<ChatMessage>
+        {
+            new(ChatRole.User, "What's the time?"),
+            new(ChatRole.Assistant, [new FunctionCallContent("call-123", "get_time")]),
+            new(ChatRole.Tool, [new FunctionResultContent("call-123", "2024-01-01T00:00:00Z")]),
+        };
+
+        await grok.GetResponseAsync(messages);
+
+        Assert.NotNull(capturedRequest);
+        var toolMessage = capturedRequest.Messages.FirstOrDefault(m => m.Role == MessageRole.RoleTool);
+        Assert.NotNull(toolMessage);
+        Assert.Equal("call-123", toolMessage.ToolCallId);
+    }
+
+    [Fact]
+    public async Task GrokSetsToolCallIdOnlyWhenCallIdIsProvided()
+    {
+        GetCompletionsRequest? capturedRequest = null;
+        var client = new Mock<xAI.Protocol.Chat.ChatClient>(MockBehavior.Strict);
+        client.Setup(x => x.GetCompletionAsync(It.IsAny<GetCompletionsRequest>(), null, null, CancellationToken.None))
+            .Callback<GetCompletionsRequest, Metadata?, DateTime?, CancellationToken>((req, _, _, _) => capturedRequest = req)
+            .Returns(CallHelpers.CreateAsyncUnaryCall(new GetChatCompletionResponse
+            {
+                Outputs =
+                {
+                    new CompletionOutput
+                    {
+                        Message = new CompletionMessage
+                        {
+                            Content = "Done"
+                        }
+                    }
+                }
+            }));
+
+        var grok = new GrokChatClient(client.Object, "grok-4-1-fast");
+        var messages = new List<ChatMessage>
+        {
+            new(ChatRole.User, "What's the time?"),
+            new(ChatRole.Assistant, [new FunctionCallContent("call-456", "get_time")]),
+            // FunctionResultContent with empty CallId
+            new(ChatRole.Tool, [new FunctionResultContent("", "2024-01-01T00:00:00Z")]),
+        };
+
+        await grok.GetResponseAsync(messages);
+
+        Assert.NotNull(capturedRequest);
+        var toolMessage = capturedRequest.Messages.FirstOrDefault(m => m.Role == MessageRole.RoleTool);
+        Assert.NotNull(toolMessage);
+        // ToolCallId should not be set if CallId is empty
+        Assert.False(toolMessage.HasToolCallId);
+    }
+
     record Response(DateOnly Today, string Release, decimal Price);
 }
diff --git a/src/xAI/GrokChatClient.cs b/src/xAI/GrokChatClient.cs
index 9f44133..84e5988 100644
--- a/src/xAI/GrokChatClient.cs
+++ b/src/xAI/GrokChatClient.cs
@@ -176,11 +176,14 @@ GetCompletionsRequest MapToRequest(IEnumerable<ChatMessage> messages, ChatOption
                 }
                 else if (content is FunctionResultContent resultContent)
                 {
-                    request.Messages.Add(new Message
+                    var msg = new Message
                     {
                         Role = MessageRole.RoleTool,
                         Content = { new Content { Text = JsonSerializer.Serialize(resultContent.Result) ?? "null" } }
-                    });
+                    };
+                    if (resultContent.CallId is { Length: > 0 } callId)
+                        msg.ToolCallId = callId;
+                    request.Messages.Add(msg);
                 }
                 else if (content is McpServerToolResultContent mcpResult &&
                     mcpResult.RawRepresentation is ToolCall mcpToolCall &&