diff --git a/main.py b/main.py
index c70a6c9..7199cb3 100644
--- a/main.py
+++ b/main.py
@@ -6,6 +6,7 @@ import io
 from collections.abc import AsyncIterator, Sequence
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
+from enum import Enum
 from typing import BinaryIO, TypedDict
 
 import aiohttp
@@ -21,6 +22,14 @@ HTTP_TOO_MANY_REQUESTS = 429
 HTTP_SERVER_ERROR = 500
 
 
+class SourceNamespace(str, Enum):
+    """Allowed values for the 'source' namespace filter."""
+
+    EDUCACION_FINANCIERA = "Educacion Financiera"
+    PRODUCTOS_Y_SERVICIOS = "Productos y Servicios"
+    FUNCIONALIDADES_APP_MOVIL = "Funcionalidades de la App Movil"
+
+
 class GoogleCloudFileStorage:
     """Cache-aware helper for downloading files from Google Cloud Storage."""
 
@@ -236,6 +245,7 @@ class GoogleCloudVectorSearch:
         deployed_index_id: str,
         query: Sequence[float],
         limit: int,
+        source: SourceNamespace | None = None,
     ) -> list[SearchResult]:
         """Run an async similarity search via the REST API.
 
@@ -243,6 +253,7 @@ class GoogleCloudVectorSearch:
             deployed_index_id: The ID of the deployed index.
             query: The embedding vector for the search query.
             limit: Maximum number of nearest neighbors to return.
+            source: Optional namespace filter to restrict results by source.
 
         Returns:
             A list of matched items with id, distance, and content.
@@ -279,11 +290,16 @@ class GoogleCloudVectorSearch:
             }
         )
 
+        datapoint: dict = {"feature_vector": list(query)}
+        if source is not None:
+            datapoint["restricts"] = [
+                {"namespace": "source", "allow_list": [source.value]},
+            ]
         payload = {
             "deployed_index_id": deployed_index_id,
             "queries": [
                 {
-                    "datapoint": {"feature_vector": list(query)},
+                    "datapoint": datapoint,
                     "neighbor_count": limit,
                 },
             ],
@@ -636,12 +652,16 @@ mcp = FastMCP(
 async def knowledge_search(
     query: str,
     ctx: Context,
+    source: SourceNamespace | None = None,
 ) -> str:
     """Search a knowledge base using a natural-language query.
 
     Args:
         query: The text query to search for.
         ctx: MCP request context (injected automatically).
+        source: Optional filter to restrict results by source.
+            Allowed values: 'Educacion Financiera',
+            'Productos y Servicios', 'Funcionalidades de la App Movil'.
 
     Returns:
         A formatted string containing matched documents with id and content.
@@ -712,6 +732,7 @@ async def knowledge_search(
                 deployed_index_id=app.settings.deployed_index_id,
                 query=embedding,
                 limit=app.settings.search_limit,
+                source=source,
             )
             t_search = time.perf_counter()
         except Exception as e:
@@ -743,6 +764,7 @@ async def knowledge_search(
                 "embedding_ms": f"{round((t_embed - t0) * 1000, 1)}ms",
                 "vector_search_ms": f"{round((t_search - t_embed) * 1000, 1)}ms",
                 "total_ms": f"{round((t_search - t0) * 1000, 1)}ms",
+                "source_filter": source.value if source is not None else None,
                 "results_count": len(search_results),
                 "chunks": [s["id"] for s in search_results]
             }