From 46f9f0fb317c4662e02b8cb19f55a9d0b16c6f2e Mon Sep 17 00:00:00 2001
From: hksdpc255 <43977088+hksdpc255@users.noreply.github.com>
Date: Mon, 30 Mar 2026 03:50:09 +1100
Subject: [PATCH] fix #1524 (#1543)

---
 examples/server/server-context.cpp |  5 +++++
 examples/server/server-task.cpp    | 16 +++++++---------
 examples/server/server-task.h      |  3 +++
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/examples/server/server-context.cpp b/examples/server/server-context.cpp
index ccaa7bd3..3daf86af 100644
--- a/examples/server/server-context.cpp
+++ b/examples/server/server-context.cpp
@@ -393,6 +393,9 @@ void server_slot::reset() {
     json_schema = json();
     generated_tool_call_ids.clear();
 
+    anthropic_thinking_block_started = false;
+    anthropic_text_block_started = false;
+
     oai_resp_thinking_block_started = false;
     oai_resp_text_block_started = false;
     oai_resp_id.clear();
@@ -1834,6 +1837,8 @@ void server_context::send_final_response(server_slot& slot) {
     res->oai_resp_reasoning_id = slot.oai_resp_reasoning_id;
     res->oai_resp_message_id = slot.oai_resp_message_id;
     res->n_decoded = slot.n_decoded;
+    res->anthropic_thinking_block_started = slot.anthropic_thinking_block_started;
+    res->anthropic_text_block_started = slot.anthropic_text_block_started;
     res->n_prompt_tokens = slot.n_prompt_tokens;
     res->oaicompat_model = slot.task->params.oaicompat_model;
     res->data = json{
diff --git a/examples/server/server-task.cpp b/examples/server/server-task.cpp
index 421f1620..561f3120 100644
--- a/examples/server/server-task.cpp
+++ b/examples/server/server-task.cpp
@@ -719,15 +719,13 @@ json server_task_result_cmpl_final::to_json_anthropic_stream() {
         stop_reason = oaicompat_msg.tool_calls.empty() ? "end_turn" : "tool_use";
     }
 
-    bool has_thinking = !oaicompat_msg.reasoning_content.empty();
-    bool has_text = !oaicompat_msg.content.empty();
     size_t num_tool_calls = oaicompat_msg.tool_calls.size();
 
     size_t thinking_block_index = 0;
-    size_t text_block_index = has_thinking ? 1 : 0;
+    size_t text_block_index = anthropic_thinking_block_started ? 1 : 0;
 
-    bool thinking_block_started = false;
-    bool text_block_started = false;
+    bool thinking_block_started = anthropic_thinking_block_started;
+    bool text_block_started = anthropic_text_block_started;
     std::set<size_t> tool_calls_started;
 
     for (const auto& diff : oaicompat_msg_diffs) {
@@ -790,7 +788,7 @@ json server_task_result_cmpl_final::to_json_anthropic_stream() {
         }
 
         if (diff.tool_call_index != std::string::npos) {
-            size_t content_block_index = (has_thinking ? 1 : 0) + (has_text ? 1 : 0) + diff.tool_call_index;
+            size_t content_block_index = (thinking_block_started ? 1 : 0) + (text_block_started ? 1 : 0) + diff.tool_call_index;
 
             if (tool_calls_started.find(diff.tool_call_index) == tool_calls_started.end()) {
                 const auto& full_tool_call = oaicompat_msg.tool_calls[diff.tool_call_index];
@@ -826,7 +824,7 @@ json server_task_result_cmpl_final::to_json_anthropic_stream() {
         }
     }
 
-    if (has_thinking) {
+    if (thinking_block_started) {
         events.push_back({
             {"event", "content_block_delta"},
             {"data", {
@@ -847,7 +845,7 @@ json server_task_result_cmpl_final::to_json_anthropic_stream() {
             });
     }
 
-    if (has_text) {
+    if (text_block_started) {
         events.push_back({
             {"event", "content_block_stop"},
             {"data", {
@@ -858,7 +856,7 @@ json server_task_result_cmpl_final::to_json_anthropic_stream() {
     }
 
     for (size_t i = 0; i < num_tool_calls; i++) {
-        size_t content_block_index = (has_thinking ? 1 : 0) + (has_text ? 1 : 0) + i;
+        size_t content_block_index = (thinking_block_started ? 1 : 0) + (text_block_started ? 1 : 0) + i;
         events.push_back({
             {"event", "content_block_stop"},
             {"data", {
diff --git a/examples/server/server-task.h b/examples/server/server-task.h
index 1cce0907..89232b3d 100644
--- a/examples/server/server-task.h
+++ b/examples/server/server-task.h
@@ -249,6 +249,9 @@ struct server_task_result_cmpl_final : server_task_result {
     std::string oai_resp_reasoning_id;
     std::string oai_resp_message_id;
 
+    bool anthropic_thinking_block_started = false;
+    bool anthropic_text_block_started = false;
+
     virtual bool is_stop() override {
         return true;
     }