diff --git a/packages/server/server_tests/memmachine_server/common/language_model/test_openai_responses_language_model.py b/packages/server/server_tests/memmachine_server/common/language_model/test_openai_responses_language_model.py
index 0f8ca7a31..5e46682ed 100644
--- a/packages/server/server_tests/memmachine_server/common/language_model/test_openai_responses_language_model.py
+++ b/packages/server/server_tests/memmachine_server/common/language_model/test_openai_responses_language_model.py
@@ -448,3 +448,83 @@ async def test_metrics_collection(mock_async_openai, full_config):
     total_counter.increment.assert_any_call(value=150)
 
     latency_histogram.observe.assert_called_once()
+
+
+@pytest.mark.asyncio
+async def test_generate_response_strips_leading_think_block(
+    mock_async_openai,
+    minimal_config,
+):
+    """generate_response strips a leading <think>...</think> block from output_text."""
+    mock_response = MagicMock()
+    mock_response.output_text = "<think>internal reasoning</think>Hello, world!"
+    mock_response.output = None
+    mock_response.usage = None
+
+    mock_client = mock_async_openai.return_value
+    mock_client.responses.create.return_value = mock_response
+
+    lm = OpenAIResponsesLanguageModel(minimal_config)
+    content, _ = await lm.generate_response(
+        system_prompt="sys",
+        user_prompt="usr",
+    )
+
+    assert content == "Hello, world!"
+
+
+@pytest.mark.asyncio
+async def test_generate_response_strips_multiline_think_block(
+    mock_async_openai,
+    minimal_config,
+):
+    """generate_response strips a multi-line <think>...</think> block from output_text."""
+    mock_response = MagicMock()
+    mock_response.output_text = '<think>\nline one\nline two\n</think>\n{"answer": 42}'
+    mock_response.output = None
+    mock_response.usage = None
+
+    mock_client = mock_async_openai.return_value
+    mock_client.responses.create.return_value = mock_response
+
+    lm = OpenAIResponsesLanguageModel(minimal_config)
+    content, _ = await lm.generate_response(
+        system_prompt="sys",
+        user_prompt="usr",
+    )
+
+    assert content == '{"answer": 42}'
+
+
+@pytest.mark.asyncio
+async def test_generate_parsed_response_fallback_strips_think_and_parses(
+    mock_async_openai,
+    minimal_config,
+):
+    """generate_parsed_response falls back to stripping think blocks and parsing
+    output_text when output_parsed is None."""
+    from pydantic import BaseModel as PydanticBaseModel
+
+    class MyModel(PydanticBaseModel):
+        value: int
+
+    mock_response = MagicMock()
+    mock_response.output_parsed = None
+    mock_response.output_text = '<think>reasoning here</think>{"value": 7}'
+    mock_response.usage = None
+
+    mock_client = mock_async_openai.return_value
+    # generate_parsed_response uses responses.parse, not responses.create
+    mock_client.with_options.return_value.responses.parse = AsyncMock(
+        return_value=mock_response
+    )
+
+    lm = OpenAIResponsesLanguageModel(minimal_config)
+    result = await lm.generate_parsed_response(
+        output_format=MyModel,
+        system_prompt="sys",
+        user_prompt="usr",
+    )
+
+    assert result is not None
+    assert result.value == 7
diff --git a/packages/server/server_tests/memmachine_server/semantic_memory/test_semantic_ingestion.py b/packages/server/server_tests/memmachine_server/semantic_memory/test_semantic_ingestion.py
index 0deea017a..7fe0b2b93 100644
--- a/packages/server/server_tests/memmachine_server/semantic_memory/test_semantic_ingestion.py
+++ b/packages/server/server_tests/memmachine_server/semantic_memory/test_semantic_ingestion.py
@@ -6,6 +6,8 @@
 import numpy as np
 import pytest
 import pytest_asyncio
+from pydantic import BaseModel as PydanticBaseModel
+from pydantic import ValidationError
 
 from memmachine_server.common.data_types import ExternalServiceAPIError
 from memmachine_server.common.episode_store import (
@@ -1003,3 +1005,113 @@ async def test_user_tags_preserved_after_ingestion_and_consolidation(
     # "bugfix" and "decision" survive (each had < 2 entries)
     assert "bugfix" in remaining_tags
     assert "decision" in remaining_tags
+
+
+def _make_validation_error() -> ValidationError:
+    """Construct a real pydantic ValidationError by feeding bad data to a trivial model."""
+
+    class _StrictModel(PydanticBaseModel):
+        x: int
+
+    try:
+        _StrictModel.model_validate({"x": "not-an-int"})
+    except ValidationError as exc:
+        return exc
+    raise AssertionError("Expected ValidationError was not raised")  # pragma: no cover
+
+
+@pytest.mark.asyncio
+async def test_validation_error_marks_message_as_ingested(
+    ingestion_service: IngestionService,
+    semantic_storage: SemanticStorage,
+    episode_storage: EpisodeStorage,
+    monkeypatch,
+):
+    """A pydantic.ValidationError from llm_feature_update causes the message to be
+    marked as ingested so it is not re-queued on the next cycle."""
+    message_id = await add_history(
+        episode_storage,
+        content="message that triggers a ValidationError",
+    )
+    await semantic_storage.add_history_to_set(
+        set_id="user-valderr",
+        history_id=message_id,
+    )
+
+    validation_error = _make_validation_error()
+
+    async def mock_validation_error(*args, **kwargs):
+        raise validation_error
+
+    monkeypatch.setattr(
+        "memmachine_server.semantic_memory.semantic_ingestion.llm_feature_update",
+        mock_validation_error,
+    )
+
+    await ingestion_service._process_single_set("user-valderr")
+
+    # Message must NOT appear in the not-yet-ingested list
+    pending = await _collect(
+        semantic_storage.get_history_messages(
+            set_ids=["user-valderr"],
+            is_ingested=False,
+        )
+    )
+    assert message_id not in pending
+
+    # Message MUST appear in the ingested list
+    ingested = await _collect(
+        semantic_storage.get_history_messages(
+            set_ids=["user-valderr"],
+            is_ingested=True,
+        )
+    )
+    assert message_id in ingested
+
+
+@pytest.mark.asyncio
+async def test_generic_exception_does_not_mark_ingested(
+    semantic_storage: SemanticStorage,
+    episode_storage: EpisodeStorage,
+    resource_retriever: MockResourceRetriever,
+    monkeypatch,
+):
+    """A generic RuntimeError from llm_feature_update must NOT mark the message as
+    ingested — guards against future over-broad widening of the ValidationError catch."""
+    message_id = await add_history(
+        episode_storage,
+        content="message that triggers a generic RuntimeError",
+    )
+    await semantic_storage.add_history_to_set(
+        set_id="user-rterr",
+        history_id=message_id,
+    )
+
+    async def mock_runtime_error(*args, **kwargs):
+        raise RuntimeError("unexpected failure")
+
+    monkeypatch.setattr(
+        "memmachine_server.semantic_memory.semantic_ingestion.llm_feature_update",
+        mock_runtime_error,
+    )
+
+    ingestion_service = IngestionService(
+        IngestionService.Params(
+            semantic_storage=semantic_storage,
+            history_store=episode_storage,
+            resource_retriever=resource_retriever.get_resources,
+            consolidated_threshold=2,
+            debug_fail_loudly=False,
+        )
+    )
+
+    await ingestion_service._process_single_set("user-rterr")
+
+    # Message must remain in the not-yet-ingested list (was NOT marked ingested)
+    pending = await _collect(
+        semantic_storage.get_history_messages(
+            set_ids=["user-rterr"],
+            is_ingested=False,
+        )
+    )
+    assert message_id in pending
diff --git a/packages/server/src/memmachine_server/common/language_model/openai_responses_language_model.py b/packages/server/src/memmachine_server/common/language_model/openai_responses_language_model.py
index 51727cbcb..41e7c7ef8 100644
--- a/packages/server/src/memmachine_server/common/language_model/openai_responses_language_model.py
+++ b/packages/server/src/memmachine_server/common/language_model/openai_responses_language_model.py
@@ -2,6 +2,7 @@
 
 import asyncio
 import logging
+import re
 from typing import Any, TypeVar, cast
 from uuid import uuid4
 
@@ -13,7 +14,7 @@
     ResponseInputParam,
     ToolParam,
 )
-from pydantic import BaseModel, Field, InstanceOf
+from pydantic import BaseModel, Field, InstanceOf, TypeAdapter
 
 from memmachine_server.common.data_types import ExternalServiceAPIError
 from memmachine_server.common.metrics_factory import MetricsFactory, OperationTracker
@@ -24,6 +25,12 @@
 
 logger = logging.getLogger(__name__)
 
+_THINK_BLOCK_RE = re.compile(r"<think>.*?</think>", re.DOTALL)
+
+
+def _strip_think_blocks(text: str) -> str:
+    return _THINK_BLOCK_RE.sub("", text).strip()
+
 
 class OpenAIResponsesLanguageModelParams(BaseModel):
     """
@@ -173,7 +180,18 @@ async def generate_parsed_response(
 
             self._collect_usage_metrics(response)
 
-            return response.output_parsed
+            if response.output_parsed is not None:
+                return response.output_parsed
+
+            raw_text = response.output_text or ""
+            if raw_text:
+                raw = _strip_think_blocks(raw_text)
+                if raw:
+                    return TypeAdapter(output_format).validate_python(
+                        json_repair.loads(raw)
+                    )
+
+            return None
 
     async def generate_response(
         self,
@@ -310,7 +328,7 @@ async def _generate_response(  # noqa: C901
             self._collect_usage_metrics(response)
 
             if response.output is None:
-                return (response.output_text or "", [], 0, 0)
+                return (_strip_think_blocks(response.output_text or ""), [], 0, 0)
 
             function_calls_arguments: list[dict[str, Any]] = []
             try:
@@ -333,7 +351,7 @@ async def _generate_response(  # noqa: C901
                 ) from e
 
             return (
-                response.output_text or "",
+                _strip_think_blocks(response.output_text or ""),
                 function_calls_arguments,
                 response.usage.input_tokens if response.usage else 0,
                 response.usage.output_tokens if response.usage else 0,
diff --git a/packages/server/src/memmachine_server/semantic_memory/semantic_ingestion.py b/packages/server/src/memmachine_server/semantic_memory/semantic_ingestion.py
index f49f491fe..697871fb8 100644
--- a/packages/server/src/memmachine_server/semantic_memory/semantic_ingestion.py
+++ b/packages/server/src/memmachine_server/semantic_memory/semantic_ingestion.py
@@ -7,7 +7,7 @@
 from itertools import chain
 
 import numpy as np
-from pydantic import BaseModel, Field, InstanceOf, TypeAdapter
+from pydantic import BaseModel, Field, InstanceOf, TypeAdapter, ValidationError
 
 from memmachine_server.common.embedder import Embedder
 from memmachine_server.common.episode_store import Episode, EpisodeIdT, EpisodeStorage
@@ -216,6 +216,21 @@ async def process_semantic_type(
                             mark_messages.append(message.uid)
                         continue
 
+                    if isinstance(err, ValidationError):
+                        logger.warning(
+                            "Skipping message %s for semantic type %s due to "
+                            "non-retryable parse error (%s): %s",
+                            message.uid,
+                            semantic_category.name,
+                            type(err).__name__,
+                            err,
+                        )
+                        if self._debug_fail_loudly:
+                            raise
+                        if message.uid not in mark_messages:
+                            mark_messages.append(message.uid)
+                        continue
+
                     logger.exception(
                         "Failed to process message %s for semantic type %s",
                         message.uid,