diff --git a/backend/app/gateway/app.py b/backend/app/gateway/app.py
index 39d17498f..01606a8cb 100644
--- a/backend/app/gateway/app.py
+++ b/backend/app/gateway/app.py
@@ -11,6 +11,7 @@ from app.gateway.routers import (
     artifacts,
     assistants_compat,
     channels,
+    feedback,
     mcp,
     memory,
     models,
@@ -199,6 +200,9 @@ This gateway provides custom endpoints for models, MCP configuration, skills, an
     # Assistants compatibility API (LangGraph Platform stub)
     app.include_router(assistants_compat.router)
 
+    # Feedback API is mounted at /api/threads/{thread_id}/runs/{run_id}/feedback
+    app.include_router(feedback.router)
+
     # Thread Runs API (LangGraph Platform-compatible runs lifecycle)
     app.include_router(thread_runs.router)
 
diff --git a/backend/app/gateway/deps.py b/backend/app/gateway/deps.py
index ebfb0c987..111dceaf5 100644
--- a/backend/app/gateway/deps.py
+++ b/backend/app/gateway/deps.py
@@ -46,6 +46,9 @@ async def langgraph_runtime(app: FastAPI) -> AsyncGenerator[None, None]:
         # Initialize run event store based on config
         app.state.run_event_store = _make_run_event_store(config)
 
+        # Initialize feedback repository (None when no DB engine)
+        app.state.feedback_repo = _make_feedback_repo()
+
         # RunManager with store backing for persistence
         app.state.run_manager = RunManager(store=app.state.run_store)
 
@@ -74,6 +77,18 @@ def _make_run_store() -> RunStore:
     return MemoryRunStore()
 
 
+def _make_feedback_repo():
+    """Create a FeedbackRepository if DB engine is available, else None."""
+    from deerflow.persistence.engine import get_session_factory
+
+    sf = get_session_factory()
+    if sf is not None:
+        from deerflow.persistence.repositories.feedback_repo import FeedbackRepository
+
+        return FeedbackRepository(sf)
+    return None
+
+
 def _make_run_event_store(config) -> RunEventStore:
     from deerflow.runtime.events.store import make_run_event_store
 
@@ -123,6 +138,14 @@ def get_run_event_store(request: Request) -> RunEventStore:
     return store
 
 
+def get_feedback_repo(request: Request):
+    """Return the FeedbackRepository, or 503 if not available."""
+    repo = getattr(request.app.state, "feedback_repo", None)
+    if repo is None:
+        raise HTTPException(status_code=503, detail="Feedback not available")
+    return repo
+
+
 def get_run_store(request: Request) -> RunStore:
     """Return the RunStore, or 503 if not available."""
     store = getattr(request.app.state, "run_store", None)
diff --git a/backend/app/gateway/routers/feedback.py b/backend/app/gateway/routers/feedback.py
new file mode 100644
index 000000000..2705ff24c
--- /dev/null
+++ b/backend/app/gateway/routers/feedback.py
@@ -0,0 +1,121 @@
+"""Feedback endpoints — create, list, stats, delete.
+
+Allows users to submit thumbs-up/down feedback on runs,
+optionally scoped to a specific message.
+"""
+
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from fastapi import APIRouter, HTTPException, Request
+from pydantic import BaseModel, Field
+
+from app.gateway.deps import get_current_user, get_feedback_repo, get_run_store
+
+logger = logging.getLogger(__name__)
+router = APIRouter(prefix="/api/threads", tags=["feedback"])
+
+
+# ---------------------------------------------------------------------------
+# Request / response models
+# ---------------------------------------------------------------------------
+
+
+class FeedbackCreateRequest(BaseModel):
+    rating: int = Field(..., description="Feedback rating: +1 (positive) or -1 (negative)")
+    comment: str | None = Field(default=None, description="Optional text feedback")
+    message_id: str | None = Field(default=None, description="Optional: scope feedback to a specific message")
+
+
+class FeedbackResponse(BaseModel):
+    feedback_id: str
+    run_id: str
+    thread_id: str
+    owner_id: str | None = None
+    message_id: str | None = None
+    rating: int
+    comment: str | None = None
+    created_at: str = ""
+
+
+class FeedbackStatsResponse(BaseModel):
+    run_id: str
+    total: int = 0
+    positive: int = 0
+    negative: int = 0
+
+
+# ---------------------------------------------------------------------------
+# Endpoints
+# ---------------------------------------------------------------------------
+
+
+@router.post("/{thread_id}/runs/{run_id}/feedback", response_model=FeedbackResponse)
+async def create_feedback(
+    thread_id: str,
+    run_id: str,
+    body: FeedbackCreateRequest,
+    request: Request,
+) -> dict[str, Any]:
+    """Submit feedback (thumbs-up/down) for a run."""
+    if body.rating not in (1, -1):
+        raise HTTPException(status_code=400, detail="rating must be +1 or -1")
+
+    user_id = await get_current_user(request)
+
+    # Validate run exists and belongs to thread
+    run_store = get_run_store(request)
+    run = await run_store.get(run_id)
+    if run is None:
+        raise HTTPException(status_code=404, detail=f"Run {run_id} not found")
+    if run.get("thread_id") != thread_id:
+        raise HTTPException(status_code=404, detail=f"Run {run_id} not found in thread {thread_id}")
+
+    feedback_repo = get_feedback_repo(request)
+    return await feedback_repo.create(
+        run_id=run_id,
+        thread_id=thread_id,
+        rating=body.rating,
+        owner_id=user_id,
+        message_id=body.message_id,
+        comment=body.comment,
+    )
+
+
+@router.get("/{thread_id}/runs/{run_id}/feedback", response_model=list[FeedbackResponse])
+async def list_feedback(
+    thread_id: str,
+    run_id: str,
+    request: Request,
+) -> list[dict[str, Any]]:
+    """List all feedback for a run."""
+    feedback_repo = get_feedback_repo(request)
+    return await feedback_repo.list_by_run(thread_id, run_id)
+
+
+@router.get("/{thread_id}/runs/{run_id}/feedback/stats", response_model=FeedbackStatsResponse)
+async def feedback_stats(
+    thread_id: str,
+    run_id: str,
+    request: Request,
+) -> dict[str, Any]:
+    """Get aggregated feedback stats (positive/negative counts) for a run."""
+    feedback_repo = get_feedback_repo(request)
+    return await feedback_repo.aggregate_by_run(thread_id, run_id)
+
+
+@router.delete("/{thread_id}/runs/{run_id}/feedback/{feedback_id}")
+async def delete_feedback(
+    thread_id: str,
+    run_id: str,
+    feedback_id: str,
+    request: Request,
+) -> dict[str, bool]:
+    """Delete a feedback record."""
+    feedback_repo = get_feedback_repo(request)
+    deleted = await feedback_repo.delete(feedback_id)
+    if not deleted:
+        raise HTTPException(status_code=404, detail=f"Feedback {feedback_id} not found")
+    return {"success": True}
diff --git a/backend/app/gateway/routers/thread_runs.py b/backend/app/gateway/routers/thread_runs.py
index 8cc944a36..f45dfc6bd 100644
--- a/backend/app/gateway/routers/thread_runs.py
+++ b/backend/app/gateway/routers/thread_runs.py
@@ -52,6 +52,7 @@ class RunCreateRequest(BaseModel):
     after_seconds: float | None = Field(default=None, description="Delayed execution")
     if_not_exists: Literal["reject", "create"] = Field(default="create", description="Thread creation policy")
     feedback_keys: list[str] | None = Field(default=None, description="LangSmith feedback keys")
+    follow_up_to_run_id: str | None = Field(default=None, description="Run ID this message follows up on. Auto-detected from latest successful run if not provided.")
 
 
 class RunResponse(BaseModel):
diff --git a/backend/app/gateway/services.py b/backend/app/gateway/services.py
index dcb79deee..a5509df33 100644
--- a/backend/app/gateway/services.py
+++ b/backend/app/gateway/services.py
@@ -17,7 +17,7 @@ from typing import Any
 from fastapi import HTTPException, Request
 from langchain_core.messages import HumanMessage
 
-from app.gateway.deps import get_checkpointer, get_run_event_store, get_run_manager, get_store, get_stream_bridge
+from app.gateway.deps import get_checkpointer, get_run_event_store, get_run_manager, get_run_store, get_store, get_stream_bridge
 from deerflow.runtime import (
     END_SENTINEL,
     HEARTBEAT_SENTINEL,
@@ -274,6 +274,17 @@ async def start_run(
     if store is not None:
         await _upsert_thread_in_store(store, thread_id, body.metadata)
 
+    # Resolve follow_up_to_run_id: explicit from request, or auto-detect from latest successful run
+    follow_up_to_run_id = getattr(body, "follow_up_to_run_id", None)
+    if follow_up_to_run_id is None:
+        run_store = get_run_store(request)
+        try:
+            recent_runs = await run_store.list_by_thread(thread_id, limit=1)
+            if recent_runs and recent_runs[0].get("status") == "success":
+                follow_up_to_run_id = recent_runs[0]["run_id"]
+        except Exception:
+            pass  # Don't block run creation
+
     agent_factory = resolve_agent_factory(body.assistant_id)
     graph_input = normalize_input(body.input)
     config = build_run_config(thread_id, body.config, body.metadata, assistant_id=body.assistant_id)
@@ -295,6 +306,7 @@ async def start_run(
             interrupt_after=body.interrupt_after,
             event_store=event_store,
             run_events_config=run_events_config,
+            follow_up_to_run_id=follow_up_to_run_id,
         )
     )
     record.task = task
diff --git a/backend/packages/harness/deerflow/persistence/models/__init__.py b/backend/packages/harness/deerflow/persistence/models/__init__.py
index 9b9bf8d39..fa4d0d1b2 100644
--- a/backend/packages/harness/deerflow/persistence/models/__init__.py
+++ b/backend/packages/harness/deerflow/persistence/models/__init__.py
@@ -1,5 +1,6 @@
+from deerflow.persistence.models.feedback import FeedbackRow
 from deerflow.persistence.models.run import RunRow
 from deerflow.persistence.models.run_event import RunEventRow
 from deerflow.persistence.models.thread_meta import ThreadMetaRow
 
-__all__ = ["RunEventRow", "RunRow", "ThreadMetaRow"]
+__all__ = ["FeedbackRow", "RunEventRow", "RunRow", "ThreadMetaRow"]
diff --git a/backend/packages/harness/deerflow/persistence/models/feedback.py b/backend/packages/harness/deerflow/persistence/models/feedback.py
new file mode 100644
index 000000000..5770a583b
--- /dev/null
+++ b/backend/packages/harness/deerflow/persistence/models/feedback.py
@@ -0,0 +1,30 @@
+"""ORM model for user feedback on runs."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+
+from sqlalchemy import String, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from deerflow.persistence.base import Base
+
+
+class FeedbackRow(Base):
+    __tablename__ = "feedback"
+
+    feedback_id: Mapped[str] = mapped_column(String(64), primary_key=True)
+    run_id: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
+    thread_id: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
+    owner_id: Mapped[str | None] = mapped_column(String(64), index=True)
+    message_id: Mapped[str | None] = mapped_column(String(64))
+    # message_id is an optional RunEventStore event identifier —
+    # allows feedback to target a specific message or the entire run
+
+    rating: Mapped[int] = mapped_column(nullable=False)
+    # +1 (thumbs-up) or -1 (thumbs-down)
+
+    comment: Mapped[str | None] = mapped_column(Text)
+    # Optional text feedback from the user
+
+    created_at: Mapped[datetime] = mapped_column(default=lambda: datetime.now(UTC))
diff --git a/backend/packages/harness/deerflow/persistence/repositories/__init__.py b/backend/packages/harness/deerflow/persistence/repositories/__init__.py
index 52c913669..0b9f76afa 100644
--- a/backend/packages/harness/deerflow/persistence/repositories/__init__.py
+++ b/backend/packages/harness/deerflow/persistence/repositories/__init__.py
@@ -1,4 +1,5 @@
+from deerflow.persistence.repositories.feedback_repo import FeedbackRepository
 from deerflow.persistence.repositories.run_repo import RunRepository
 from deerflow.persistence.repositories.thread_meta_repo import ThreadMetaRepository
 
-__all__ = ["RunRepository", "ThreadMetaRepository"]
+__all__ = ["FeedbackRepository", "RunRepository", "ThreadMetaRepository"]
diff --git a/backend/packages/harness/deerflow/persistence/repositories/feedback_repo.py b/backend/packages/harness/deerflow/persistence/repositories/feedback_repo.py
new file mode 100644
index 000000000..1903a0db2
--- /dev/null
+++ b/backend/packages/harness/deerflow/persistence/repositories/feedback_repo.py
@@ -0,0 +1,97 @@
+"""SQLAlchemy-backed feedback storage.
+
+Each method acquires its own short-lived session.
+"""
+
+from __future__ import annotations
+
+import logging
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+
+from deerflow.persistence.models.feedback import FeedbackRow
+
+logger = logging.getLogger(__name__)
+
+
+class FeedbackRepository:
+    def __init__(self, session_factory: async_sessionmaker[AsyncSession]) -> None:
+        self._sf = session_factory
+
+    @staticmethod
+    def _row_to_dict(row: FeedbackRow) -> dict:
+        d = row.to_dict()
+        val = d.get("created_at")
+        if isinstance(val, datetime):
+            d["created_at"] = val.isoformat()
+        return d
+
+    async def create(
+        self,
+        *,
+        run_id: str,
+        thread_id: str,
+        rating: int,
+        owner_id: str | None = None,
+        message_id: str | None = None,
+        comment: str | None = None,
+    ) -> dict:
+        """Create a feedback record. rating must be +1 or -1."""
+        if rating not in (1, -1):
+            raise ValueError(f"rating must be +1 or -1, got {rating}")
+        row = FeedbackRow(
+            feedback_id=str(uuid.uuid4()),
+            run_id=run_id,
+            thread_id=thread_id,
+            owner_id=owner_id,
+            message_id=message_id,
+            rating=rating,
+            comment=comment,
+            created_at=datetime.now(UTC),
+        )
+        async with self._sf() as session:
+            session.add(row)
+            await session.commit()
+            await session.refresh(row)
+            return self._row_to_dict(row)
+
+    async def get(self, feedback_id: str) -> dict | None:
+        async with self._sf() as session:
+            row = await session.get(FeedbackRow, feedback_id)
+            return self._row_to_dict(row) if row else None
+
+    async def list_by_run(self, thread_id: str, run_id: str, *, limit: int = 100) -> list[dict]:
+        stmt = select(FeedbackRow).where(FeedbackRow.thread_id == thread_id, FeedbackRow.run_id == run_id).order_by(FeedbackRow.created_at.asc()).limit(limit)
+        async with self._sf() as session:
+            result = await session.execute(stmt)
+            return [self._row_to_dict(r) for r in result.scalars()]
+
+    async def list_by_thread(self, thread_id: str, *, limit: int = 100) -> list[dict]:
+        stmt = select(FeedbackRow).where(FeedbackRow.thread_id == thread_id).order_by(FeedbackRow.created_at.asc()).limit(limit)
+        async with self._sf() as session:
+            result = await session.execute(stmt)
+            return [self._row_to_dict(r) for r in result.scalars()]
+
+    async def delete(self, feedback_id: str) -> bool:
+        async with self._sf() as session:
+            row = await session.get(FeedbackRow, feedback_id)
+            if row is None:
+                return False
+            await session.delete(row)
+            await session.commit()
+            return True
+
+    async def aggregate_by_run(self, thread_id: str, run_id: str) -> dict:
+        """Aggregate feedback stats for a run."""
+        items = await self.list_by_run(thread_id, run_id, limit=10000)
+        positive = sum(1 for i in items if i["rating"] == 1)
+        negative = sum(1 for i in items if i["rating"] == -1)
+        return {
+            "run_id": run_id,
+            "total": len(items),
+            "positive": positive,
+            "negative": negative,
+        }
diff --git a/backend/packages/harness/deerflow/runtime/runs/worker.py b/backend/packages/harness/deerflow/runtime/runs/worker.py
index 82b77ca1e..765a4327f 100644
--- a/backend/packages/harness/deerflow/runtime/runs/worker.py
+++ b/backend/packages/harness/deerflow/runtime/runs/worker.py
@@ -47,6 +47,7 @@ async def run_agent(
     interrupt_after: list[str] | Literal["*"] | None = None,
     event_store: Any | None = None,
     run_events_config: Any | None = None,
+    follow_up_to_run_id: str | None = None,
 ) -> None:
     """Execute an agent in the background, publishing events to *bridge*."""
 
@@ -69,12 +70,16 @@ async def run_agent(
         # Write human_message event
         user_input = _extract_user_input(graph_input)
         if user_input:
+            msg_metadata = {}
+            if follow_up_to_run_id:
+                msg_metadata["follow_up_to_run_id"] = follow_up_to_run_id
             await event_store.put(
                 thread_id=thread_id,
                 run_id=run_id,
                 event_type="human_message",
                 category="message",
                 content=user_input,
+                metadata=msg_metadata or None,
             )
             journal.set_first_human_message(user_input)
 
diff --git a/backend/tests/test_feedback.py b/backend/tests/test_feedback.py
new file mode 100644
index 000000000..863da7ef9
--- /dev/null
+++ b/backend/tests/test_feedback.py
@@ -0,0 +1,210 @@
+"""Tests for FeedbackRepository and follow-up association.
+
+Uses temp SQLite DB for ORM tests.
+"""
+
+import pytest
+
+from deerflow.persistence.repositories.feedback_repo import FeedbackRepository
+
+
+async def _make_feedback_repo(tmp_path):
+    from deerflow.persistence.engine import get_session_factory, init_engine
+
+    url = f"sqlite+aiosqlite:///{tmp_path / 'test.db'}"
+    await init_engine("sqlite", url=url, sqlite_dir=str(tmp_path))
+    return FeedbackRepository(get_session_factory())
+
+
+async def _cleanup():
+    from deerflow.persistence.engine import close_engine
+
+    await close_engine()
+
+
+# -- FeedbackRepository --
+
+
+class TestFeedbackRepository:
+    @pytest.mark.anyio
+    async def test_create_positive(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        record = await repo.create(run_id="r1", thread_id="t1", rating=1)
+        assert record["feedback_id"]
+        assert record["rating"] == 1
+        assert record["run_id"] == "r1"
+        assert record["thread_id"] == "t1"
+        assert "created_at" in record
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_create_negative_with_comment(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        record = await repo.create(
+            run_id="r1", thread_id="t1", rating=-1, comment="Response was inaccurate",
+        )
+        assert record["rating"] == -1
+        assert record["comment"] == "Response was inaccurate"
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_create_with_message_id(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        record = await repo.create(run_id="r1", thread_id="t1", rating=1, message_id="msg-42")
+        assert record["message_id"] == "msg-42"
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_create_with_owner(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        record = await repo.create(run_id="r1", thread_id="t1", rating=1, owner_id="user-1")
+        assert record["owner_id"] == "user-1"
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_create_invalid_rating_zero(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        with pytest.raises(ValueError):
+            await repo.create(run_id="r1", thread_id="t1", rating=0)
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_create_invalid_rating_five(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        with pytest.raises(ValueError):
+            await repo.create(run_id="r1", thread_id="t1", rating=5)
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_get(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        created = await repo.create(run_id="r1", thread_id="t1", rating=1)
+        fetched = await repo.get(created["feedback_id"])
+        assert fetched is not None
+        assert fetched["feedback_id"] == created["feedback_id"]
+        assert fetched["rating"] == 1
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_get_nonexistent(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        assert await repo.get("nonexistent") is None
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_list_by_run(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        await repo.create(run_id="r1", thread_id="t1", rating=1)
+        await repo.create(run_id="r1", thread_id="t1", rating=-1)
+        await repo.create(run_id="r2", thread_id="t1", rating=1)
+        results = await repo.list_by_run("t1", "r1")
+        assert len(results) == 2
+        assert all(r["run_id"] == "r1" for r in results)
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_list_by_thread(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        await repo.create(run_id="r1", thread_id="t1", rating=1)
+        await repo.create(run_id="r2", thread_id="t1", rating=-1)
+        await repo.create(run_id="r3", thread_id="t2", rating=1)
+        results = await repo.list_by_thread("t1")
+        assert len(results) == 2
+        assert all(r["thread_id"] == "t1" for r in results)
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_delete(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        created = await repo.create(run_id="r1", thread_id="t1", rating=1)
+        assert await repo.delete(created["feedback_id"]) is True
+        assert await repo.get(created["feedback_id"]) is None
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_delete_nonexistent(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        assert await repo.delete("nonexistent") is False
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_aggregate_by_run(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        await repo.create(run_id="r1", thread_id="t1", rating=1)
+        await repo.create(run_id="r1", thread_id="t1", rating=1)
+        await repo.create(run_id="r1", thread_id="t1", rating=-1)
+        stats = await repo.aggregate_by_run("t1", "r1")
+        assert stats["total"] == 3
+        assert stats["positive"] == 2
+        assert stats["negative"] == 1
+        assert stats["run_id"] == "r1"
+        await _cleanup()
+
+    @pytest.mark.anyio
+    async def test_aggregate_empty(self, tmp_path):
+        repo = await _make_feedback_repo(tmp_path)
+        stats = await repo.aggregate_by_run("t1", "r1")
+        assert stats["total"] == 0
+        assert stats["positive"] == 0
+        assert stats["negative"] == 0
+        await _cleanup()
+
+
+# -- Follow-up association --
+
+
+class TestFollowUpAssociation:
+    @pytest.mark.anyio
+    async def test_run_records_follow_up_via_memory_store(self):
+        """MemoryRunStore stores follow_up_to_run_id in kwargs."""
+        from deerflow.runtime.runs.store.memory import MemoryRunStore
+
+        store = MemoryRunStore()
+        await store.put("r1", thread_id="t1", status="success")
+        # MemoryRunStore doesn't have follow_up_to_run_id as a top-level param,
+        # but it can be passed via metadata
+        await store.put("r2", thread_id="t1", metadata={"follow_up_to_run_id": "r1"})
+        run = await store.get("r2")
+        assert run["metadata"]["follow_up_to_run_id"] == "r1"
+
+    @pytest.mark.anyio
+    async def test_human_message_has_follow_up_metadata(self):
+        """human_message event metadata includes follow_up_to_run_id."""
+        from deerflow.runtime.events.store.memory import MemoryRunEventStore
+
+        event_store = MemoryRunEventStore()
+        await event_store.put(
+            thread_id="t1",
+            run_id="r2",
+            event_type="human_message",
+            category="message",
+            content="Tell me more about that",
+            metadata={"follow_up_to_run_id": "r1"},
+        )
+        messages = await event_store.list_messages("t1")
+        assert messages[0]["metadata"]["follow_up_to_run_id"] == "r1"
+
+    @pytest.mark.anyio
+    async def test_follow_up_auto_detection_logic(self):
+        """Simulate the auto-detection: latest successful run becomes follow_up_to."""
+        from deerflow.runtime.runs.store.memory import MemoryRunStore
+
+        store = MemoryRunStore()
+        await store.put("r1", thread_id="t1", status="success")
+        await store.put("r2", thread_id="t1", status="error")
+
+        # Auto-detect: list_by_thread returns newest first
+        recent = await store.list_by_thread("t1", limit=1)
+        follow_up = None
+        if recent and recent[0].get("status") == "success":
+            follow_up = recent[0]["run_id"]
+        # r2 (error) is newest, so no follow_up detected
+        assert follow_up is None
+
+        # Now add a successful run
+        await store.put("r3", thread_id="t1", status="success")
+        recent = await store.list_by_thread("t1", limit=1)
+        follow_up = None
+        if recent and recent[0].get("status") == "success":
+            follow_up = recent[0]["run_id"]
+        assert follow_up == "r3"