diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index 1c145b3a0..6912ffe19 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -2,3 +2,8 @@
 **Vulnerability:** User-provided string fields (like project and connection names) lacked strict validation against control characters, only relying on length constraints.
 **Learning:** This could potentially lead to Log Injection (CRLF injection), Null Byte Injection, or terminal escape injection if these strings are subsequently logged or rendered directly.
 **Prevention:** Use explicit regex validation `pattern=r'^[^\x00-\x1F\x7F]+$'` on Pydantic string fields to strictly reject control characters.
+
+## 2025-02-23 - Hardening Pydantic String Fields Against Control Characters (Part 2)
+**Vulnerability:** Additional user-provided string fields (`DiagramViewCreateIn.name`, `TableAnnotationUpsertIn.schema_name`, `TableAnnotationUpsertIn.relation_name`, `ApiKeyCreateIn.key_name`) lacked strict validation against control characters.
+**Learning:** This could potentially lead to Log Injection (CRLF injection), Null Byte Injection, or terminal escape injection if these strings are subsequently logged or rendered directly. Furthermore, adding explicit `# SECURITY: ...` comments alongside the validation helps future developers understand the necessity of the regex pattern.
+**Prevention:** Use explicit regex validation `pattern=r'^[^\x00-\x1F\x7F]+$'` on all Pydantic string fields to strictly reject control characters, and document the reason with inline security comments.
diff --git a/backend/app/schemas.py b/backend/app/schemas.py
index d7c6de77d..6b7177a60 100644
--- a/backend/app/schemas.py
+++ b/backend/app/schemas.py
@@ -190,7 +190,8 @@ class IndexRedundancyOut(BaseModel):
 class DiagramViewCreateIn(BaseModel):
     """Request body for saving an ERD canvas view."""
 
-    name: str = Field(min_length=1, max_length=200)
+    name: str = Field(min_length=1, max_length=200, pattern=r"^[^\x00-\x1F\x7F]+$")
+    # SECURITY: Prevent control character injection (e.g. CRLF, Null Byte)
     # Opaque client layout (node positions, hidden tables, viewport). The API
     # bounds the serialized size in the endpoint to prevent abuse.
     layout_json: dict
@@ -214,8 +215,10 @@ class DiagramViewDetailOut(DiagramViewOut):
 class TableAnnotationUpsertIn(BaseModel):
     """Request body for creating/updating a table annotation."""
 
-    schema_name: str = Field(min_length=1, max_length=255)
-    relation_name: str = Field(min_length=1, max_length=255)
+    schema_name: str = Field(min_length=1, max_length=255, pattern=r"^[^\x00-\x1F\x7F]+$")
+    # SECURITY: Prevent control character injection (e.g. CRLF, Null Byte)
+    relation_name: str = Field(min_length=1, max_length=255, pattern=r"^[^\x00-\x1F\x7F]+$")
+    # SECURITY: Prevent control character injection (e.g. CRLF, Null Byte)
     body: str = Field(min_length=1, max_length=10_000)
 
 
@@ -302,7 +305,8 @@ class DbmlConvertOut(BaseModel):
 class ApiKeyCreateIn(BaseModel):
     """Request body for creating an API key."""
 
-    key_name: str = Field(min_length=1, max_length=128)
+    key_name: str = Field(min_length=1, max_length=128, pattern=r"^[^\x00-\x1F\x7F]+$")
+    # SECURITY: Prevent control character injection (e.g. CRLF, Null Byte)
 
 
 class ApiKeyOut(BaseModel):
diff --git a/backend/tests/test_schema_validation.py b/backend/tests/test_schema_validation.py
index 317292b86..183114985 100644
--- a/backend/tests/test_schema_validation.py
+++ b/backend/tests/test_schema_validation.py
@@ -37,3 +37,27 @@ def test_conn_name_rejects_control_characters() -> None:
         ConnectionCreateIn(conn_name="my\x00conn", dsn="postgresql://localhost/db")
     with pytest.raises(ValidationError):
         ConnectionCreateIn(conn_name="my\nconn", dsn="postgresql://localhost/db")
+
+from app.schemas import ApiKeyCreateIn, DiagramViewCreateIn, TableAnnotationUpsertIn
+
+def test_diagram_view_create_in_rejects_control_characters() -> None:
+    with pytest.raises(ValidationError):
+        DiagramViewCreateIn(name="View\nNewline", layout_json={})
+    with pytest.raises(ValidationError):
+        DiagramViewCreateIn(name="View\x00Null", layout_json={})
+
+def test_table_annotation_upsert_in_rejects_control_characters() -> None:
+    with pytest.raises(ValidationError):
+        TableAnnotationUpsertIn(
+            schema_name="schema\n", relation_name="valid_table", body="some body"
+        )
+    with pytest.raises(ValidationError):
+        TableAnnotationUpsertIn(
+            schema_name="valid_schema", relation_name="table\x00", body="some body"
+        )
+
+def test_api_key_create_in_rejects_control_characters() -> None:
+    with pytest.raises(ValidationError):
+        ApiKeyCreateIn(key_name="Key\nNewline")
+    with pytest.raises(ValidationError):
+        ApiKeyCreateIn(key_name="Key\x00Null")