diff --git a/datamind/capabilities/db/base.py b/datamind/capabilities/db/base.py
index d0bfeab..0ebfc32 100644
--- a/datamind/capabilities/db/base.py
+++ b/datamind/capabilities/db/base.py
@@ -106,6 +106,8 @@ async def execute_readonly(
     ) -> QueryResult:
         if not sql or not sql.strip():
             raise CapabilityError("db", "Empty SQL")
+        if row_limit < 1:
+            raise CapabilityError("db", "row_limit must be at least 1")
         if contains_multiple_statements(sql):
             raise MultiStatementSQLError(
                 "multiple statements are not allowed (use a single SELECT)"
diff --git a/datamind/capabilities/hooks/audit.py b/datamind/capabilities/hooks/audit.py
index b1b69dd..268bd0e 100644
--- a/datamind/capabilities/hooks/audit.py
+++ b/datamind/capabilities/hooks/audit.py
@@ -16,9 +16,9 @@
 
 Secret redaction: arg values whose KEY matches a redaction regex
 (`api_key`, `password`, `token`, `secret`, ...) are replaced with
-`"[REDACTED]"` before logging. Values are not scanned (we trust the
-caller to put secrets in well-named fields, which is true across
-DataMind's own tools).
+`"[REDACTED]"` before logging. Credential-shaped values in exception
+text are redacted as well because provider and transport errors commonly
+include the rejected request detail.
 
 Concurrency: writes are serialised via an asyncio.Lock per AuditLogHook
 instance. For multi-process deployments use one process per profile
@@ -45,6 +45,13 @@
     r"(?i)(api[_-]?key|password|passwd|token|secret|authorization|bearer|access[_-]?key|client[_-]?secret)"
 )
 _REDACTED = "[REDACTED]"
+_BEARER_TEXT_RE = re.compile(r"(?i)\bBearer\s+([^\s,;]+)")
+_SECRET_TEXT_RE = re.compile(
+    r"(?i)([\"']?"
+    r"(?:api[_-]?key|password|passwd|token|secret|authorization|access[_-]?key|client[_-]?secret)"
+    r"[\"']?\s*[:=]\s*)([\"']?)([^\s,;}\"']+)([\"']?)"
+)
+_RAW_SECRET_RE = re.compile(r"\bsk-[A-Za-z0-9_-]{8,}\b")
 
 _HASH_HEX_LEN = 16  # truncated SHA-256 hex; 64 bits of collision resistance
 
@@ -74,6 +81,16 @@ def _redact(value: Any) -> Any:
     return value
 
 
+def _redact_text(value: str) -> str:
+    """Redact common credential formats embedded in diagnostic text."""
+    value = _BEARER_TEXT_RE.sub(f"Bearer {_REDACTED}", value)
+    value = _SECRET_TEXT_RE.sub(
+        lambda match: f"{match.group(1)}{match.group(2)}{_REDACTED}{match.group(4)}",
+        value,
+    )
+    return _RAW_SECRET_RE.sub(_REDACTED, value)
+
+
 def _decision_to_record(decision: HookDecision) -> dict[str, Any]:
     if isinstance(decision, Allow):
         return {"kind": "allow"}
@@ -163,7 +180,7 @@ async def post_tool_use(
             "error": (
                 None
                 if error is None
-                else f"{type(error).__name__}: {error}"
+                else _redact_text(f"{type(error).__name__}: {error}")
             ),
         }
         await self._append(record)
diff --git a/datamind/capabilities/ingest/service.py b/datamind/capabilities/ingest/service.py
index b04387e..124cd3c 100644
--- a/datamind/capabilities/ingest/service.py
+++ b/datamind/capabilities/ingest/service.py
@@ -725,6 +725,9 @@ async def kb_add_file(self, *, path: str, copy_to_profile: bool = True) -> dict[
             ))
 
         if not chunks:
+            await self._upsert_chunks(
+                chunks, replace_sources={source, str(resolved)},
+            )
             return {"file": str(resolved), "chunks_added": 0, "note": "file was empty"}
 
         parsed_chunks = None
@@ -818,8 +821,6 @@ async def _upsert_chunks(
             raise CapabilityError("ingest", "KB surface is disabled")
         provider = self._kb.embedding
         store = self._kb.vector_store
-        texts = [c.text for c in chunks]
-        vectors = await provider.embed_texts(texts)
         stale_ids: list[str] = []
         if replace_sources:
             new_ids = {chunk.id for chunk in chunks}
@@ -830,6 +831,13 @@ async def _upsert_chunks(
                 }
                 if recorded_sources & replace_sources and chunk_id not in new_ids:
                     stale_ids.append(chunk_id)
+        if not chunks:
+            if stale_ids:
+                await store.delete(stale_ids)
+            await self._kb.record_incremental_ingest()
+            return
+        texts = [c.text for c in chunks]
+        vectors = await provider.embed_texts(texts)
         await store.add(
             ids=[c.id for c in chunks],
             texts=texts,
@@ -882,12 +890,25 @@ async def db_import_csv(
 
         # Sanitise column names: same rule as table names.
         safe_cols: list[str] = []
-        for raw in header:
+        used_cols: set[str] = set()
+        for index, raw in enumerate(header, start=1):
             col = raw.strip()
             if not re.fullmatch(r"[A-Za-z_][A-Za-z0-9_]{0,63}", col):
                 # Fall back to col_<idx> if header is unusable.
-                col = f"col_{len(safe_cols) + 1}"
+                col = f"col_{index}"
+            if col.casefold() in used_cols:
+                # SQL tables cannot contain duplicate column names. Keep the
+                # first header unchanged and give later occurrences a stable
+                # fallback name without losing their values in the row dict.
+                base = f"col_{index}"
+                col = base
+                suffix = 2
+                while col.casefold() in used_cols:
+                    suffix_text = f"_{suffix}"
+                    col = f"{base[:64 - len(suffix_text)]}{suffix_text}"
+                    suffix += 1
             safe_cols.append(col)
+            used_cols.add(col.casefold())
 
         rows: list[dict[str, str]] = []
         for raw_row in reader:
diff --git a/datamind/capabilities/memory/providers/sqlite_store.py b/datamind/capabilities/memory/providers/sqlite_store.py
index b9cd08e..5dadad8 100644
--- a/datamind/capabilities/memory/providers/sqlite_store.py
+++ b/datamind/capabilities/memory/providers/sqlite_store.py
@@ -287,14 +287,32 @@ async def recall(
         session_id: str | None = None,
         top_k: int = 8,
         kinds: Sequence[str] | None = None,
+        scope_filter: Sequence[str] | None = None,
         include_archived: bool = False,
         # advanced — let callers tune the per-scope budget for ablation
         per_scope: dict[str, int] | None = None,
     ) -> list[MemoryItem]:
+        valid_scopes = {"session", "profile", "global"}
+        allowed_scopes = valid_scopes if scope_filter is None else set(scope_filter)
+        invalid_scopes = allowed_scopes - valid_scopes
+        if invalid_scopes:
+            raise CapabilityError(
+                "memory", f"unsupported scope filter: {sorted(invalid_scopes)!r}"
+            )
+        if not allowed_scopes:
+            return []
+
         # Default per-scope budget: 2 (session) + 4 (profile) + 2 (global) = 8.
-        budgets: dict[str, int] = {"session": 2, "profile": 4, "global": 2}
+        budgets: dict[str, int] = {
+            "session": 2 if "session" in allowed_scopes else 0,
+            "profile": 4 if "profile" in allowed_scopes else 0,
+            "global": 2 if "global" in allowed_scopes else 0,
+        }
         if per_scope:
-            budgets.update({k: v for k, v in per_scope.items() if k in budgets})
+            budgets.update({
+                k: v for k, v in per_scope.items()
+                if k in budgets and k in allowed_scopes
+            })
 
         # If no embedding, fall back to lexical scoring within the same
         # scope filters so the contract stays identical.
diff --git a/datamind/capabilities/memory/service.py b/datamind/capabilities/memory/service.py
index 882b858..078304d 100644
--- a/datamind/capabilities/memory/service.py
+++ b/datamind/capabilities/memory/service.py
@@ -92,14 +92,25 @@ async def recall(
         session_id: str | None = None,
         top_k: int = 8,
         kinds: Sequence[str] | None = None,
+        scope_filter: Sequence[str] | None = None,
         include_archived: bool = False,
     ) -> list[dict[str, Any]]:
+        allowed = None if scope_filter is None else set(scope_filter)
+        effective_profile = (
+            profile or self._default_profile
+            if allowed is None or "profile" in allowed
+            else None
+        )
+        effective_session = (
+            session_id if allowed is None or "session" in allowed else None
+        )
         hits = await self.long_term.recall(
             query,
-            profile=profile or self._default_profile,
-            session_id=session_id,
+            profile=effective_profile,
+            session_id=effective_session,
             top_k=top_k,
             kinds=kinds,
+            scope_filter=scope_filter,
             include_archived=include_archived,
         )
         return [h.model_dump() for h in hits]
diff --git a/datamind/capabilities/memory/tools.py b/datamind/capabilities/memory/tools.py
index a328fa3..dc5eb50 100644
--- a/datamind/capabilities/memory/tools.py
+++ b/datamind/capabilities/memory/tools.py
@@ -82,6 +82,7 @@ async def _recall(
             session_id=eff_session,
             top_k=top_k,
             kinds=kinds,
+            scope_filter=scope_filter,
         )
         return {"query": query, "count": len(hits), "results": hits}
 
diff --git a/datamind/config.py b/datamind/config.py
index 8f182d3..cc5e304 100644
--- a/datamind/config.py
+++ b/datamind/config.py
@@ -113,7 +113,7 @@ class DBConfig(BaseModel):
     dialect: str = "sqlite"  # sqlite | mysql | postgres | ...
     dsn: str | None = None   # e.g. mysql+pymysql://user:pw@host/db
     read_only: bool = True
-    row_limit: int = 1000
+    row_limit: int = Field(default=1000, ge=1)
     query_timeout_s: float = 10.0
 
 
diff --git a/datamind/core/protocols.py b/datamind/core/protocols.py
index e680186..c64c747 100644
--- a/datamind/core/protocols.py
+++ b/datamind/core/protocols.py
@@ -374,6 +374,7 @@ async def recall(
         session_id: str | None = None,
         top_k: int = 8,
         kinds: Sequence[str] | None = None,
+        scope_filter: Sequence[str] | None = None,
         include_archived: bool = False,
     ) -> list[MemoryItem]: ...
 
diff --git a/datamind/tests/test_config.py b/datamind/tests/test_config.py
index dab841e..e5c1d13 100644
--- a/datamind/tests/test_config.py
+++ b/datamind/tests/test_config.py
@@ -14,7 +14,7 @@
 import pytest
 from pydantic import ValidationError
 
-from datamind.config import DataConfig, Settings
+from datamind.config import DBConfig, DataConfig, Settings
 
 
 def test_nested_env_hydrates_required_llm(monkeypatch, tmp_path):
@@ -116,3 +116,8 @@ def test_profile_assignment_keeps_path_boundary(tmp_path):
     config = DataConfig(base_dir=tmp_path)
     with pytest.raises(ValidationError):
         config.profile = "../escape"
+
+
+def test_db_config_rejects_nonpositive_row_limit():
+    with pytest.raises(ValidationError):
+        DBConfig(row_limit=0)
diff --git a/datamind/tests/test_db_safeguard.py b/datamind/tests/test_db_safeguard.py
index bda0bd6..874043f 100644
--- a/datamind/tests/test_db_safeguard.py
+++ b/datamind/tests/test_db_safeguard.py
@@ -12,6 +12,8 @@
     leading_verb,
     strip_comments,
 )
+from datamind.capabilities.db.providers.sqlite import SQLiteDialect
+from datamind.core.errors import CapabilityError
 
 
 @pytest.mark.parametrize(
@@ -67,3 +69,17 @@ def test_ensure_row_limit_strips_trailing_semicolon():
 def test_strip_comments():
     assert strip_comments("SELECT /* x */ 1") == "SELECT  1"
     assert strip_comments("-- line\nSELECT 1") == "\nSELECT 1"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("row_limit", [0, -1])
+async def test_execute_readonly_rejects_nonpositive_row_limit(tmp_path, row_limit):
+    dialect = SQLiteDialect()
+    engine = dialect.build_engine(
+        None, default_path=str(tmp_path / "db.sqlite")
+    )
+
+    with pytest.raises(CapabilityError, match="row_limit"):
+        await dialect.execute_readonly(
+            engine, "SELECT 1", row_limit=row_limit
+        )
diff --git a/datamind/tests/test_hooks.py b/datamind/tests/test_hooks.py
index 55b5567..6a72719 100644
--- a/datamind/tests/test_hooks.py
+++ b/datamind/tests/test_hooks.py
@@ -322,6 +322,48 @@ async def test_audit_log_redacts_secret_keys(tmp_path: Path):
     assert rec["args"]["username"] == "ann"
 
 
+@pytest.mark.asyncio
+async def test_audit_log_redacts_secrets_in_errors(tmp_path: Path):
+    audit = tmp_path / "audit.jsonl"
+    hook = AuditLogHook(audit_path=audit)
+    await hook.post_tool_use(
+        _ctx(),
+        "fake_tool",
+        {},
+        result=None,
+        error=RuntimeError(
+            "request failed: api_key=sk-live-secret Authorization: Bearer bearer-secret"
+        ),
+    )
+
+    rec = json.loads(audit.read_text().splitlines()[-1])
+    assert "sk-live-secret" not in rec["error"]
+    assert "bearer-secret" not in rec["error"]
+    assert "[REDACTED]" in rec["error"]
+
+
+@pytest.mark.asyncio
+async def test_audit_log_redacts_quoted_url_and_raw_secrets_in_errors(tmp_path: Path):
+    audit = tmp_path / "audit.jsonl"
+    hook = AuditLogHook(audit_path=audit)
+    secrets = ["sk-json-secret1", "sk-query-secret2", "sk-raw-secret3"]
+    await hook.post_tool_use(
+        _ctx(),
+        "fake_tool",
+        {},
+        result=None,
+        error=RuntimeError(
+            '{"api_key": "sk-json-secret1"} '
+            "https://example.test?access_token=sk-query-secret2 "
+            "provider rejected sk-raw-secret3"
+        ),
+    )
+
+    rec = json.loads(audit.read_text().splitlines()[-1])
+    assert all(secret not in rec["error"] for secret in secrets)
+    assert rec["error"].count("[REDACTED]") >= 3
+
+
 @pytest.mark.asyncio
 async def test_audit_log_records_denied_decision(tmp_path: Path):
     audit = tmp_path / "audit.jsonl"
diff --git a/datamind/tests/test_ingest_revisions.py b/datamind/tests/test_ingest_revisions.py
index bcf4ed7..926790d 100644
--- a/datamind/tests/test_ingest_revisions.py
+++ b/datamind/tests/test_ingest_revisions.py
@@ -7,6 +7,8 @@
 
 class _Embedding:
     async def embed_texts(self, texts):
+        if not texts:
+            raise AssertionError("empty revisions must not call the embedding provider")
         return [[float(len(text))] for text in texts]
 
 
@@ -43,6 +45,34 @@ async def generate_text(self, prompt, **kwargs):
         return "[]"
 
 
+@pytest.mark.asyncio
+async def test_reingesting_empty_path_removes_old_kb_chunks(tmp_path: Path):
+    profile = tmp_path / "profile"
+    uploads = profile / "uploads"
+    uploads.mkdir(parents=True)
+    source = uploads / "release_note.txt"
+    kb = _KB()
+    service = IngestService(
+        kb=kb,
+        db=None,
+        graph=None,
+        llm_client=_Model(),
+        llm_model="test",
+        profile_data_dir=profile,
+        chunk_size=512,
+        chunk_overlap=64,
+    )
+
+    source.write_text("old release note", encoding="utf-8")
+    await service.kb_add_file(path=str(source))
+    source.write_text("\n\n", encoding="utf-8")
+
+    result = await service.kb_add_file(path=str(source))
+
+    assert result["chunks_added"] == 0
+    assert kb.vector_store.items == {}
+
+
 @pytest.mark.asyncio
 async def test_reingesting_same_path_replaces_old_kb_chunks(tmp_path: Path):
     profile = tmp_path / "profile"
diff --git a/datamind/tests/test_memory.py b/datamind/tests/test_memory.py
index 9b9c452..3a1b495 100644
--- a/datamind/tests/test_memory.py
+++ b/datamind/tests/test_memory.py
@@ -8,8 +8,10 @@
 from datamind.capabilities.memory import (
     MemoryService,
     ShortTermMemory,
+    build_memory_tools,
 )
 from datamind.capabilities.memory.providers.sqlite_store import SQLiteMemoryStore
+from datamind.core.errors import CapabilityError
 from datamind.core.protocols import MemoryStore
 
 
@@ -276,6 +278,52 @@ async def test_service_combines_short_and_long(tmp_path):
     assert await svc.forget(rid)
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    ("scope_filter", "expected"),
+    [
+        (None, {"global", "profile", "session"}),
+        (["global"], {"global"}),
+        (["profile"], {"profile"}),
+        (["session"], {"session"}),
+        (["global", "profile"], {"global", "profile"}),
+        ([], set()),
+    ],
+)
+async def test_memory_recall_scope_filter_is_exact(tmp_path, scope_filter, expected):
+    lt = SQLiteMemoryStore(db_path=str(tmp_path / "m.db"), embedding=_FakeEmbed())
+    svc = MemoryService(
+        short_term=ShortTermMemory(max_turns=5),
+        long_term=lt,
+        default_profile="acme",
+    )
+    tools = {tool.name: tool.handler for tool in build_memory_tools(svc)}
+
+    await tools["memory_save"]("global fact", scope="global")
+    await tools["memory_save"]("profile fact", scope="profile", profile="acme")
+    await tools["memory_save"](
+        "session fact", scope="session", session_id="chat-1"
+    )
+
+    result = await tools["memory_recall"](
+        "fact",
+        profile="acme",
+        session_id="chat-1",
+        scope_filter=scope_filter,
+    )
+    assert {item["scope"] for item in result["results"]} == expected
+
+
+@pytest.mark.asyncio
+async def test_memory_recall_rejects_unknown_scope_filter(tmp_path):
+    lt = SQLiteMemoryStore(db_path=str(tmp_path / "m.db"), embedding=_FakeEmbed())
+    svc = MemoryService(
+        short_term=ShortTermMemory(max_turns=5), long_term=lt, default_profile="acme"
+    )
+    with pytest.raises(CapabilityError, match="unsupported scope filter"):
+        await svc.recall("fact", scope_filter=["other"])
+
+
 @pytest.mark.asyncio
 async def test_service_default_profile_used_when_omitted(tmp_path):
     """save without explicit profile should land under default_profile."""
diff --git a/datamind/tests/test_replace_receipts.py b/datamind/tests/test_replace_receipts.py
index ee4b2d6..34c56de 100644
--- a/datamind/tests/test_replace_receipts.py
+++ b/datamind/tests/test_replace_receipts.py
@@ -77,3 +77,33 @@ async def test_append_retry_remains_deduplicated(database, tmp_path):
     assert second["results"][0]["status"] == "unchanged"
     assert second["revision"] == first["revision"]
     assert (await db.query_sql("SELECT amount FROM sales")).rows == [["200"]]
+
+
+@pytest.mark.asyncio
+async def test_csv_import_keeps_duplicate_headers_as_distinct_columns(database, tmp_path):
+    db, raw = database
+    source = tmp_path / "duplicate-columns.csv"
+    source.write_text("a,a\nfirst,second\n", encoding="utf-8")
+
+    receipt = await raw.get("db_import_csv").handler(
+        path=str(source), table="duplicate_columns", if_exists="replace"
+    )
+
+    assert receipt["columns"] == ["a", "col_2"]
+    assert (await db.query_sql("SELECT * FROM duplicate_columns")).rows == [["first", "second"]]
+
+
+@pytest.mark.asyncio
+async def test_csv_import_deduplicates_case_insensitive_headers(database, tmp_path):
+    db, raw = database
+    source = tmp_path / "case-columns.csv"
+    source.write_text("a,A,col_3,col_3\n1,2,3,4\n", encoding="utf-8")
+
+    receipt = await raw.get("db_import_csv").handler(
+        path=str(source), table="case_columns", if_exists="replace"
+    )
+
+    assert receipt["columns"] == ["a", "col_2", "col_3", "col_4"]
+    assert (await db.query_sql("SELECT * FROM case_columns")).rows == [
+        ["1", "2", "3", "4"]
+    ]