diff --git a/surfsense_backend/app/agents/new_chat/memory_extraction.py b/surfsense_backend/app/agents/new_chat/memory_extraction.py
index ceff6ff41..e9f060457 100644
--- a/surfsense_backend/app/agents/new_chat/memory_extraction.py
+++ b/surfsense_backend/app/agents/new_chat/memory_extraction.py
@@ -1,11 +1,8 @@
 """Background memory extraction for the SurfSense agent.
 
 After each agent response, if the agent did not call ``update_memory`` during
-the turn, this module runs a lightweight LLM call to decide whether the user's
-message contains any long-term information worth persisting.
-
-Only user (personal) memory is handled here — team memory relies on explicit
-agent calls.
+the turn, this module can run a lightweight LLM call to decide whether the
+latest message contains long-term information worth persisting.
 """
 
 from __future__ import annotations
@@ -18,7 +15,7 @@ from langchain_core.messages import HumanMessage
 from sqlalchemy import select
 
 from app.agents.new_chat.tools.update_memory import _save_memory
-from app.db import User, shielded_async_session
+from app.db import SearchSpace, User, shielded_async_session
 
 logger = logging.getLogger(__name__)
 
@@ -55,6 +52,51 @@ If nothing is worth remembering, output exactly: NO_UPDATE
 {user_message}
 </user_message>"""
 
+_TEAM_MEMORY_EXTRACT_PROMPT = """\
+You are a team-memory extraction assistant. Analyze the latest message and \
+decide if it contains durable TEAM-level information worth persisting.
+
+High-precision rule: if uncertain, output NO_UPDATE.
+
+Worth remembering (team-level only):
+- Explicit decisions (e.g. "we decided to use X")
+- Team conventions/standards (naming, review policy, coding norms)
+- Long-lived architecture/process facts
+- Stable project constraints, owners, recurring schedules
+
+NOT worth remembering:
+- Personal preferences or biography of one person
+- Questions, brainstorming, tentative ideas, or speculation
+- One-off requests, status updates, TODOs, logistics for this session
+- Anything not clearly adopted by the team
+
+If the message contains memorizable team information, output the FULL updated \
+team memory document with new facts merged into existing content. Follow rules:
+- Use the same ## section structure as the existing memory.
+- Keep entries as single concise bullet points (under 120 chars each).
+- Every bullet MUST start with a (YYYY-MM-DD) date prefix.
+- If a new fact contradicts an existing entry, update the existing entry.
+- Do not duplicate existing information.
+- NEVER use personal sections like "## About the user", "## Preferences", \
+  or "## Instructions".
+- Preserve neutral team phrasing; avoid person-specific memory unless role-anchored.
+- Standard sections: "## Team decisions", "## Team conventions", \
+"## Key facts", "## Current priorities"
+
+If nothing is worth remembering, output exactly: NO_UPDATE
+
+<current_team_memory>
+{current_memory}
+</current_team_memory>
+
+<latest_message_author>
+{author}
+</latest_message_author>
+
+<latest_message>
+{user_message}
+</latest_message>"""
+
 
 async def extract_and_save_memory(
     *,
@@ -105,6 +147,7 @@ async def extract_and_save_memory(
                 commit_fn=session.commit,
                 rollback_fn=session.rollback,
                 label="memory",
+                scope="user",
             )
             logger.info(
                 "Background memory extraction for user %s: %s",
@@ -113,3 +156,69 @@ async def extract_and_save_memory(
             )
     except Exception:
         logger.exception("Background user memory extraction failed")
+
+
+async def extract_and_save_team_memory(
+    *,
+    user_message: str,
+    search_space_id: int | None,
+    llm: Any,
+    author_display_name: str | None = None,
+) -> None:
+    """Background task: extract team-level memory and persist it.
+
+    Runs only for shared threads. Designed to be fire-and-forget and catches
+    exceptions internally.
+    """
+    if not search_space_id:
+        return
+
+    try:
+        async with shielded_async_session() as session:
+            result = await session.execute(
+                select(SearchSpace).where(SearchSpace.id == search_space_id)
+            )
+            space = result.scalars().first()
+            if not space:
+                return
+
+            old_memory = space.shared_memory_md
+            prompt = _TEAM_MEMORY_EXTRACT_PROMPT.format(
+                current_memory=old_memory or "(empty)",
+                author=author_display_name or "Unknown team member",
+                user_message=user_message,
+            )
+            response = await llm.ainvoke(
+                [HumanMessage(content=prompt)],
+                config={"tags": ["surfsense:internal", "team-memory-extraction"]},
+            )
+            text = (
+                response.content
+                if isinstance(response.content, str)
+                else str(response.content)
+            ).strip()
+
+            if text == "NO_UPDATE" or not text:
+                logger.debug(
+                    "Team memory extraction: no update needed (space %s)",
+                    search_space_id,
+                )
+                return
+
+            save_result = await _save_memory(
+                updated_memory=text,
+                old_memory=old_memory,
+                llm=llm,
+                apply_fn=lambda content: setattr(space, "shared_memory_md", content),
+                commit_fn=session.commit,
+                rollback_fn=session.rollback,
+                label="team memory",
+                scope="team",
+            )
+            logger.info(
+                "Background team memory extraction for space %s: %s",
+                search_space_id,
+                save_result.get("status"),
+            )
+    except Exception:
+        logger.exception("Background team memory extraction failed")
diff --git a/surfsense_backend/app/agents/new_chat/middleware/memory_injection.py b/surfsense_backend/app/agents/new_chat/middleware/memory_injection.py
index 137a71edf..74a9611fd 100644
--- a/surfsense_backend/app/agents/new_chat/middleware/memory_injection.py
+++ b/surfsense_backend/app/agents/new_chat/middleware/memory_injection.py
@@ -1,10 +1,8 @@
 """Memory injection middleware for the SurfSense agent.
 
-Loads the user's personal memory (User.memory_md) and, for shared threads,
-the team memory (SearchSpace.shared_memory_md) from the database and injects
-them into the system prompt as <user_memory> / <team_memory> XML blocks on
-every turn.  This ensures the LLM always has the full memory context without
-requiring a tool call.
+Injects memory markdown into the system prompt on every turn:
+- Private threads: only personal memory (<user_memory>)
+- Shared threads: only team memory (<team_memory>)
 """
 
 from __future__ import annotations
@@ -58,7 +56,25 @@ class MemoryInjectionMiddleware(AgentMiddleware):  # type: ignore[type-arg]
         memory_blocks: list[str] = []
 
         async with shielded_async_session() as session:
-            if self.user_id is not None:
+            if self.visibility == ChatVisibility.SEARCH_SPACE:
+                team_memory = await self._load_team_memory(session)
+                if team_memory:
+                    chars = len(team_memory)
+                    memory_blocks.append(
+                        f'<team_memory chars="{chars}" limit="{MEMORY_HARD_LIMIT}">\n'
+                        f"{team_memory}\n"
+                        f"</team_memory>"
+                    )
+                    if chars > MEMORY_SOFT_LIMIT:
+                        memory_blocks.append(
+                            f"<memory_warning>Team memory is at "
+                            f"{chars:,}/{MEMORY_HARD_LIMIT:,} characters and approaching "
+                            f"the hard limit. On your next update_memory call, consolidate "
+                            f"by merging duplicates, removing outdated entries, and "
+                            f"shortening descriptions before adding anything new."
+                            f"</memory_warning>"
+                        )
+            elif self.user_id is not None:
                 user_memory, display_name = await self._load_user_memory(session)
                 if display_name:
                     first_name = display_name.split()[0]
@@ -80,25 +96,6 @@ class MemoryInjectionMiddleware(AgentMiddleware):  # type: ignore[type-arg]
                             f"</memory_warning>"
                         )
 
-            if self.visibility == ChatVisibility.SEARCH_SPACE:
-                team_memory = await self._load_team_memory(session)
-                if team_memory:
-                    chars = len(team_memory)
-                    memory_blocks.append(
-                        f'<team_memory chars="{chars}" limit="{MEMORY_HARD_LIMIT}">\n'
-                        f"{team_memory}\n"
-                        f"</team_memory>"
-                    )
-                    if chars > MEMORY_SOFT_LIMIT:
-                        memory_blocks.append(
-                            f"<memory_warning>Team memory is at "
-                            f"{chars:,}/{MEMORY_HARD_LIMIT:,} characters and approaching "
-                            f"the hard limit. On your next update_memory call, consolidate "
-                            f"by merging duplicates, removing outdated entries, and "
-                            f"shortening descriptions before adding anything new."
-                            f"</memory_warning>"
-                        )
-
         if not memory_blocks:
             return None
 
diff --git a/surfsense_backend/app/agents/new_chat/system_prompt.py b/surfsense_backend/app/agents/new_chat/system_prompt.py
index 403019d96..e310d02eb 100644
--- a/surfsense_backend/app/agents/new_chat/system_prompt.py
+++ b/surfsense_backend/app/agents/new_chat/system_prompt.py
@@ -284,9 +284,13 @@ _MEMORY_TOOL_INSTRUCTIONS: dict[str, dict[str, str]] = {
   - Every bullet MUST start with a (YYYY-MM-DD) date prefix indicating when it was recorded or last updated.
   - Keep it concise and well under the character limit shown in <user_memory>.
   - You MUST organize memory using these standard sections (add new `##` sections only if none of the standard ones fit):
-    ## About the user — role, background, company
-    ## Preferences — languages, tools, frameworks, response style
-    ## Instructions — standing instructions, things to always/never do
+    ## About the user
+    ## Preferences
+    ## Instructions
+  - Section guidance:
+    * About the user: role, background, company, durable identity context
+    * Preferences: languages, tools, frameworks, response style preferences
+    * Instructions: standing instructions, things to always/never do
   - Each entry MUST be a single bullet point. Keep entries concise (aim for under 120 chars each).
   - During consolidation, prioritize keeping: identity/instructions > preferences.
 """,
@@ -295,6 +299,8 @@ _MEMORY_TOOL_INSTRUCTIONS: dict[str, dict[str, str]] = {
   - Your current team memory is already in <team_memory> in your context.  The `chars`
     and `limit` attributes show current usage and the maximum allowed size.
   - This is the team's curated long-term memory — decisions, conventions, key facts.
+  - NEVER store personal memory in team memory (e.g. personal bio, individual
+    preferences, or user-only standing instructions).
   - Call update_memory when:
     * A team member explicitly asks to remember or forget something
     * The conversation surfaces durable team decisions, conventions, or facts
@@ -308,10 +314,15 @@ _MEMORY_TOOL_INSTRUCTIONS: dict[str, dict[str, str]] = {
   - Every bullet MUST start with a (YYYY-MM-DD) date prefix indicating when it was recorded or last updated.
   - Keep it concise and well under the character limit shown in <team_memory>.
   - You MUST organize memory using these standard sections (add new `##` sections only if none of the standard ones fit):
-    ## Team decisions — agreed-upon choices with rationale
-    ## Conventions — coding standards, tools, processes, naming patterns
-    ## Key facts — where things are, how things work, team structure
-    ## Current priorities — active projects, deadlines, blockers
+    ## Team decisions
+    ## Conventions
+    ## Key facts
+    ## Current priorities
+  - Section guidance:
+    * Team decisions: agreed choices and durable technical/product decisions
+    * Conventions: coding standards, tools, processes, naming patterns
+    * Key facts: stable facts about org/team/system setup
+    * Current priorities: active projects, near-term goals, important blockers
   - Each entry MUST be a single bullet point. Keep entries concise (aim for under 120 chars each).
   - During consolidation, prioritize keeping: decisions/conventions > key facts > current priorities.
 """,
diff --git a/surfsense_backend/app/agents/new_chat/tools/update_memory.py b/surfsense_backend/app/agents/new_chat/tools/update_memory.py
index e8eb967fa..24577e975 100644
--- a/surfsense_backend/app/agents/new_chat/tools/update_memory.py
+++ b/surfsense_backend/app/agents/new_chat/tools/update_memory.py
@@ -18,7 +18,7 @@ from __future__ import annotations
 
 import logging
 import re
-from typing import Any
+from typing import Any, Literal
 from uuid import UUID
 
 from langchain_core.messages import HumanMessage
@@ -34,6 +34,15 @@ MEMORY_SOFT_LIMIT = 18_000
 MEMORY_HARD_LIMIT = 25_000
 
 _SECTION_HEADING_RE = re.compile(r"^##\s+(.+)$", re.MULTILINE)
+_HEADING_NORMALIZE_RE = re.compile(r"\s+")
+
+_USER_ONLY_HEADINGS = {"about the user", "preferences", "instructions"}
+_TEAM_ONLY_HEADINGS = {
+    "team decisions",
+    "conventions",
+    "key facts",
+    "current priorities",
+}
 
 
 # ---------------------------------------------------------------------------
@@ -46,6 +55,45 @@ def _extract_headings(memory: str) -> set[str]:
     return set(_SECTION_HEADING_RE.findall(memory))
 
 
+def _normalize_heading(heading: str) -> str:
+    """Normalize heading text for robust scope checks."""
+    return _HEADING_NORMALIZE_RE.sub(" ", heading.strip().lower())
+
+
+def _validate_memory_scope(
+    content: str, scope: Literal["user", "team"]
+) -> dict[str, Any] | None:
+    """Reject cross-scope headings (user sections in team memory and vice versa)."""
+    headings = {_normalize_heading(h) for h in _extract_headings(content)}
+    if not headings:
+        return None
+
+    if scope == "team":
+        leaked = sorted(headings & _USER_ONLY_HEADINGS)
+        if leaked:
+            return {
+                "status": "error",
+                "message": (
+                    "Team memory cannot include personal sections: "
+                    + ", ".join(leaked)
+                    + ". Use team sections only."
+                ),
+            }
+        return None
+
+    leaked = sorted(headings & _TEAM_ONLY_HEADINGS)
+    if leaked:
+        return {
+            "status": "error",
+            "message": (
+                "User memory cannot include team sections: "
+                + ", ".join(leaked)
+                + ". Use personal sections only."
+            ),
+        }
+    return None
+
+
 def _validate_diff(old_memory: str | None, new_memory: str) -> list[str]:
     """Return a list of warning strings about suspicious changes."""
     if not old_memory:
@@ -166,6 +214,7 @@ async def _save_memory(
     commit_fn,
     rollback_fn,
     label: str,
+    scope: Literal["user", "team"],
 ) -> dict[str, Any]:
     """Validate, optionally force-rewrite if over the hard limit, save, and
     return a response dict.
@@ -200,6 +249,10 @@ async def _save_memory(
     if size_err:
         return size_err
 
+    scope_err = _validate_memory_scope(content, scope)
+    if scope_err:
+        return scope_err
+
     # --- persist ---
     try:
         apply_fn(content)
@@ -270,6 +323,7 @@ def create_update_memory_tool(
                 commit_fn=db_session.commit,
                 rollback_fn=db_session.rollback,
                 label="memory",
+                scope="user",
             )
         except Exception as e:
             logger.exception("Failed to update user memory: %s", e)
@@ -319,6 +373,7 @@ def create_update_team_memory_tool(
                 commit_fn=db_session.commit,
                 rollback_fn=db_session.rollback,
                 label="team memory",
+                scope="team",
             )
         except Exception as e:
             logger.exception("Failed to update team memory: %s", e)
diff --git a/surfsense_backend/app/routes/memory_routes.py b/surfsense_backend/app/routes/memory_routes.py
index 6ec535626..565656f60 100644
--- a/surfsense_backend/app/routes/memory_routes.py
+++ b/surfsense_backend/app/routes/memory_routes.py
@@ -132,6 +132,7 @@ async def edit_user_memory(
         commit_fn=session.commit,
         rollback_fn=session.rollback,
         label="memory",
+        scope="user",
     )
 
     if result.get("status") == "error":
diff --git a/surfsense_backend/app/routes/search_spaces_routes.py b/surfsense_backend/app/routes/search_spaces_routes.py
index d29315c80..6c608c532 100644
--- a/surfsense_backend/app/routes/search_spaces_routes.py
+++ b/surfsense_backend/app/routes/search_spaces_routes.py
@@ -56,7 +56,9 @@ RULES:
 2. If the instruction asks to remove something, remove the matching entry.
 3. If the instruction asks to change something, update the matching entry.
 4. Preserve the existing ## section structure and all other entries.
-5. Output ONLY the updated markdown — no explanations, no wrapping.
+5. NEVER use personal sections like "## About the user", "## Preferences", or
+   "## Instructions". Team memory must stay team-scoped.
+6. Output ONLY the updated markdown — no explanations, no wrapping.
 
 <current_memory>
 {current_memory}
@@ -372,6 +374,7 @@ async def edit_team_memory(
         commit_fn=session.commit,
         rollback_fn=session.rollback,
         label="team memory",
+        scope="team",
     )
 
     if save_result.get("status") == "error":
diff --git a/surfsense_backend/app/tasks/chat/stream_new_chat.py b/surfsense_backend/app/tasks/chat/stream_new_chat.py
index 3c7b9af7e..fd118528e 100644
--- a/surfsense_backend/app/tasks/chat/stream_new_chat.py
+++ b/surfsense_backend/app/tasks/chat/stream_new_chat.py
@@ -37,7 +37,10 @@ from app.agents.new_chat.llm_config import (
     load_agent_config,
     load_llm_config_from_yaml,
 )
-from app.agents.new_chat.memory_extraction import extract_and_save_memory
+from app.agents.new_chat.memory_extraction import (
+    extract_and_save_memory,
+    extract_and_save_team_memory,
+)
 from app.db import (
     ChatVisibility,
     NewChatMessage,
@@ -1545,15 +1548,26 @@ async def stream_new_chat(
                     chat_id, generated_title
                 )
 
-        # Fire background memory extraction if the agent didn't handle it
-        if not stream_result.agent_called_update_memory and user_id:
-            asyncio.create_task(
-                extract_and_save_memory(
-                    user_message=user_query,
-                    user_id=user_id,
-                    llm=llm,
+        # Fire background memory extraction if the agent didn't handle it.
+        # Shared threads write to team memory; private threads write to user memory.
+        if not stream_result.agent_called_update_memory:
+            if visibility == ChatVisibility.SEARCH_SPACE:
+                asyncio.create_task(
+                    extract_and_save_team_memory(
+                        user_message=user_query,
+                        search_space_id=search_space_id,
+                        llm=llm,
+                        author_display_name=current_user_display_name,
+                    )
+                )
+            elif user_id:
+                asyncio.create_task(
+                    extract_and_save_memory(
+                        user_message=user_query,
+                        user_id=user_id,
+                        llm=llm,
+                    )
                 )
-            )
 
         # Finish the step and message
         yield streaming_service.format_finish_step()
diff --git a/surfsense_backend/tests/unit/agents/new_chat/tools/test_update_memory_scope.py b/surfsense_backend/tests/unit/agents/new_chat/tools/test_update_memory_scope.py
new file mode 100644
index 000000000..caef29623
--- /dev/null
+++ b/surfsense_backend/tests/unit/agents/new_chat/tools/test_update_memory_scope.py
@@ -0,0 +1,83 @@
+"""Unit tests for memory scope validation."""
+
+import pytest
+
+from app.agents.new_chat.tools.update_memory import _save_memory, _validate_memory_scope
+
+pytestmark = pytest.mark.unit
+
+
+class _Recorder:
+    def __init__(self) -> None:
+        self.applied_content: str | None = None
+        self.commit_calls = 0
+        self.rollback_calls = 0
+
+    def apply(self, content: str) -> None:
+        self.applied_content = content
+
+    async def commit(self) -> None:
+        self.commit_calls += 1
+
+    async def rollback(self) -> None:
+        self.rollback_calls += 1
+
+
+def test_validate_memory_scope_rejects_user_sections_in_team_scope() -> None:
+    content = "## About the user\n- (2026-04-10) Student studying DSA\n"
+    result = _validate_memory_scope(content, "team")
+    assert result is not None
+    assert result["status"] == "error"
+    assert "personal sections" in result["message"]
+
+
+def test_validate_memory_scope_rejects_team_sections_in_user_scope() -> None:
+    content = "## Team decisions\n- (2026-04-10) Python-first backend policy\n"
+    result = _validate_memory_scope(content, "user")
+    assert result is not None
+    assert result["status"] == "error"
+    assert "team sections" in result["message"]
+
+
+def test_validate_memory_scope_normalizes_heading_case_and_spacing() -> None:
+    content = "##   About   The   User  \n- (2026-04-10) Student\n"
+    result = _validate_memory_scope(content, "team")
+    assert result is not None
+    assert result["status"] == "error"
+
+
+@pytest.mark.asyncio
+async def test_save_memory_blocks_cross_scope_write_before_commit() -> None:
+    recorder = _Recorder()
+    result = await _save_memory(
+        updated_memory="## About the user\n- (2026-04-10) Student\n",
+        old_memory=None,
+        llm=None,
+        apply_fn=recorder.apply,
+        commit_fn=recorder.commit,
+        rollback_fn=recorder.rollback,
+        label="team memory",
+        scope="team",
+    )
+    assert result["status"] == "error"
+    assert recorder.commit_calls == 0
+    assert recorder.applied_content is None
+
+
+@pytest.mark.asyncio
+async def test_save_memory_allows_valid_scope_and_commits() -> None:
+    recorder = _Recorder()
+    content = "## Team decisions\n- (2026-04-10) Python-first backend policy\n"
+    result = await _save_memory(
+        updated_memory=content,
+        old_memory=None,
+        llm=None,
+        apply_fn=recorder.apply,
+        commit_fn=recorder.commit,
+        rollback_fn=recorder.rollback,
+        label="team memory",
+        scope="team",
+    )
+    assert result["status"] == "saved"
+    assert recorder.commit_calls == 1
+    assert recorder.applied_content == content