fix(title_generator): strip think blocks from LLM output before extracting title

Think-enabled models (MiniMax M2.7, DeepSeek, etc.) emit inline
<think>...</think> reasoning even for simple prompts like title
generation, and the raw XML was leaking into session titles. Route the
title-model response through the canonical strip_think_blocks scrubber
before cleanup so every tag variant — closed pairs, unterminated blocks,
orphan closes, mixed case — is handled, not just a single literal
<think> pair.

- 2 regression tests: closed <think> pair stripped, unterminated block
  at start yields no title.

Salvaged from PR #44126 by @shawchanshek.

agent/title_generator.py

@@ -87,7 +87,15 @@ def generate_title(
             timeout=timeout,
             main_runtime=main_runtime,
         )
-        title = (response.choices[0].message.content or "").strip()
+        content = response.choices[0].message.content or ""
+        # Strip thinking/reasoning blocks that think-enabled models
+        # (MiniMax M2.7, DeepSeek, etc.) emit even for simple prompts like
+        # title generation. Without this the raw <think>...</think> XML
+        # leaks into session titles. Reuses the canonical scrubber so all
+        # tag variants (unterminated blocks, orphan closes, mixed case)
+        # are handled, not just a single literal <think> pair.
+        from agent.agent_runtime_helpers import strip_think_blocks
+        title = strip_think_blocks(None, content).strip()
         # Clean up: remove quotes, trailing punctuation, prefixes like "Title: "
         title = title.strip('"\'')
         if title.lower().startswith("title:"):

scripts/release.py

@@ -48,6 +48,7 @@ AUTHOR_MAP = {
     "gary@bitcryptic.com": "bitcryptic-gw",  # PR #53997 salvage (Matrix E2EE: resolve device_id via query_keys({mxid: []}) when whoami returns none; guard verification call sites so query_keys is never sent [null]; reset _device_id_unverified at connect() start; disconnect before reconnect)
     "7698789+abchiaravalle@users.noreply.github.com": "abchiaravalle",  # PR #46997 salvage (recover resume_pending sessions: dual freshness signal + empty-turn safety net so restart auto-resume never sends a blank user turn)
     "swissly@users.noreply.github.com": "swissly",  # PR #47167 salvage (wrap cron delivery thread-pool fallback in its own try/except so a per-target failure can't escape the except-RuntimeError block and crash the multi-target delivery loop; #47163)
+    "53571168+shawchanshek@users.noreply.github.com": "shawchanshek",  # PR #44126 salvage (strip <think>...</think> reasoning blocks from title-generator LLM output via the canonical strip_think_blocks scrubber so reasoning-model output can't leak into session titles)
     "30854794+YLChen-007@users.noreply.github.com": "YLChen-007",  # PR #27289 salvage (case-insensitive streaming reasoning-tag filter in cli.py _stream_delta + gateway stream_consumer so mixed-case variants like <Think>/<ThInK> are suppressed, not just the hardcoded case literals)
     "27672904+kangsoo-bit@users.noreply.github.com": "kangsoo-bit",  # PR #47508 salvage (keep Telegram gateway alive on transient bootstrap network errors: best-effort deleteWebhook + resilient start_polling degrade to background recovery instead of failing startup)
     "259353979+testingbuddies24@users.noreply.github.com": "testingbuddies24",  # PR #43192 salvage (strip orphan think-tag close tags in progressive gateway stream so a bare </think> whose open was dropped upstream can't leak to the user)

tests/agent/test_title_generator.py

@@ -99,6 +99,37 @@ class TestGenerateTitle:
             title = generate_title("how do I set up docker", "First install...")
             assert title == "Setting Up Docker Environment"
 
+    def test_strips_think_blocks(self):
+        """Reasoning-model output wrapped in <think>...</think> must not
+        leak into the session title."""
+        mock_response = MagicMock()
+        mock_response.choices = [MagicMock()]
+        mock_response.choices[0].message.content = (
+            "<think>The user wants a title. I'll summarize the topic "
+            "concisely.</think>Debugging Python Import Errors"
+        )
+
+        with patch("agent.title_generator.call_llm", return_value=mock_response):
+            title = generate_title("help me fix this import", "Sure...")
+            assert title == "Debugging Python Import Errors"
+            assert "<think>" not in title
+            assert "summarize" not in title
+
+    def test_strips_unterminated_think_block(self):
+        """An unterminated <think> block (no close tag) must still be
+        stripped so the leaked reasoning doesn't become the title."""
+        mock_response = MagicMock()
+        mock_response.choices = [MagicMock()]
+        mock_response.choices[0].message.content = (
+            "<think>Let me reason about a good title for this session"
+        )
+
+        with patch("agent.title_generator.call_llm", return_value=mock_response):
+            title = generate_title("hello", "hi there")
+            # Everything from the unterminated open tag onward is stripped,
+            # leaving nothing → None.
+            assert title is None
+
     def test_strips_title_prefix(self):
         mock_response = MagicMock()
         mock_response.choices = [MagicMock()]