From 82ee6d4410cfad52b0d5d73d00737864297a9950 Mon Sep 17 00:00:00 2001
From: Javinator9889 <dev@javinator9889.com>
Date: Fri, 18 Sep 2026 12:42:31 +0200
Subject: [PATCH] fix: drop a tool call that generation never finished

When neither </tool_call> nor </function> is present the call was cut off,
normally by the output limit while writing a large argument. Taking the
remainder of the text fabricates a complete-looking call from a partial one,
and the client cannot tell: the arguments JSON is well formed because it is
rebuilt from the parsed parameters. A shell heredoc cut mid-body becomes an
unterminated `cat <<EOF` that hangs whatever runs it.

Drop the block instead. The response still carries finish_reason "length",
which is the honest signal to retry with a larger budget. The </function>
fallback is kept: a block missing only the outer tag is complete.

Measured on qwen3.5:9b, a 300-line heredoc at max_tokens=400:
before, tool_calls=true with 1580 chars of arguments and no closing EOF;
after, tool_calls=false with finish_reason "length". A complete call is
unaffected: finish_reason "tool_calls", arguments {"command":"echo hello"}.

Refs #741
---
 src/common/AutoModel/modeling_qwen3_5_omni.cpp | 11 ++++++++++-
 src/common/AutoModel/modeling_qwen3_5vl.cpp    | 11 ++++++++++-
 src/common/AutoModel/modeling_qwen3_6_moe.cpp  | 11 ++++++++++-
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/common/AutoModel/modeling_qwen3_5_omni.cpp b/src/common/AutoModel/modeling_qwen3_5_omni.cpp
index 28695786d..682fcaa0e 100644
--- a/src/common/AutoModel/modeling_qwen3_5_omni.cpp
+++ b/src/common/AutoModel/modeling_qwen3_5_omni.cpp
@@ -793,7 +793,16 @@ NonStreamResult Qwen3_5_Omni::parse_nstream_content(const std::string response_t
             if (func_end_pos != std::string::npos) {
                 block_end = func_end_pos + func_end_tag.length();
             } else {
-                block_end = response_text.length();
+                // Neither closing tag is present, so generation stopped inside
+                // the call -- almost always because it hit the output limit
+                // while writing a large argument. Taking the remainder here
+                // fabricates a complete-looking call from a partial one: the
+                // arguments JSON is well formed, because it is rebuilt from the
+                // parsed parameters, so the client cannot tell it is truncated
+                // and runs it. A heredoc cut mid-body becomes an unterminated
+                // `cat <<EOF`. Drop the block instead; the response still
+                // carries finish_reason "length", which is the honest signal.
+                break;
             }
             search_from = block_end;
         }
diff --git a/src/common/AutoModel/modeling_qwen3_5vl.cpp b/src/common/AutoModel/modeling_qwen3_5vl.cpp
index 21b759ef5..8142a5fc0 100644
--- a/src/common/AutoModel/modeling_qwen3_5vl.cpp
+++ b/src/common/AutoModel/modeling_qwen3_5vl.cpp
@@ -496,7 +496,16 @@ NonStreamResult Qwen3_5VL::parse_nstream_content(const std::string response_text
             if (func_end_pos != std::string::npos) {
                 block_end = func_end_pos + func_end_tag.length();
             } else {
-                block_end = response_text.length();
+                // Neither closing tag is present, so generation stopped inside
+                // the call -- almost always because it hit the output limit
+                // while writing a large argument. Taking the remainder here
+                // fabricates a complete-looking call from a partial one: the
+                // arguments JSON is well formed, because it is rebuilt from the
+                // parsed parameters, so the client cannot tell it is truncated
+                // and runs it. A heredoc cut mid-body becomes an unterminated
+                // `cat <<EOF`. Drop the block instead; the response still
+                // carries finish_reason "length", which is the honest signal.
+                break;
             }
             search_from = block_end;
         }
diff --git a/src/common/AutoModel/modeling_qwen3_6_moe.cpp b/src/common/AutoModel/modeling_qwen3_6_moe.cpp
index 5fc8ead51..612e82292 100644
--- a/src/common/AutoModel/modeling_qwen3_6_moe.cpp
+++ b/src/common/AutoModel/modeling_qwen3_6_moe.cpp
@@ -496,7 +496,16 @@ NonStreamResult Qwen3_6_MOE::parse_nstream_content(const std::string response_te
             if (func_end_pos != std::string::npos) {
                 block_end = func_end_pos + func_end_tag.length();
             } else {
-                block_end = response_text.length();
+                // Neither closing tag is present, so generation stopped inside
+                // the call -- almost always because it hit the output limit
+                // while writing a large argument. Taking the remainder here
+                // fabricates a complete-looking call from a partial one: the
+                // arguments JSON is well formed, because it is rebuilt from the
+                // parsed parameters, so the client cannot tell it is truncated
+                // and runs it. A heredoc cut mid-body becomes an unterminated
+                // `cat <<EOF`. Drop the block instead; the response still
+                // carries finish_reason "length", which is the honest signal.
+                break;
             }
             search_from = block_end;
         }