diff --git a/src/Abstractions/src/IVectorCollection.cs b/src/Abstractions/src/IVectorCollection.cs
index 4877ea6..d3448ef 100644
--- a/src/Abstractions/src/IVectorCollection.cs
+++ b/src/Abstractions/src/IVectorCollection.cs
@@ -63,7 +63,7 @@ Task<VectorSearchResponse> SearchAsync(
     /// <param name="filters">The filters to apply to the search request.</param>
     /// <param name="cancellationToken">The cancellation token.</param>
     /// <returns>A task representing the asynchronous operation. The task result contains the search response.</returns>
-    Task<List<Vector>> SearchByMetadata(
+    Task<IReadOnlyList<Vector>> SearchByMetadata(
         Dictionary<string, object> filters,
         CancellationToken cancellationToken = default);
 
diff --git a/src/Abstractions/src/PublicAPI.Unshipped.txt b/src/Abstractions/src/PublicAPI.Unshipped.txt
index 724ee6e..3f78cd2 100644
--- a/src/Abstractions/src/PublicAPI.Unshipped.txt
+++ b/src/Abstractions/src/PublicAPI.Unshipped.txt
@@ -14,7 +14,7 @@ LangChain.Databases.IVectorCollection.Id.get -> string!
 LangChain.Databases.IVectorCollection.IsEmptyAsync(System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task<bool>!
 LangChain.Databases.IVectorCollection.Name.get -> string!
 LangChain.Databases.IVectorCollection.SearchAsync(LangChain.Databases.VectorSearchRequest! request, LangChain.Databases.VectorSearchSettings? settings = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task<LangChain.Databases.VectorSearchResponse!>!
-LangChain.Databases.IVectorCollection.SearchByMetadata(System.Collections.Generic.Dictionary<string!, object!>! filters, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task<System.Collections.Generic.List<LangChain.Databases.Vector!>!>!
+LangChain.Databases.IVectorCollection.SearchByMetadata(System.Collections.Generic.Dictionary<string!, object!>! filters, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task<System.Collections.Generic.IReadOnlyList<LangChain.Databases.Vector!>!>!
 LangChain.Databases.IVectorDatabase
 LangChain.Databases.IVectorDatabase.CreateCollectionAsync(string! collectionName, int dimensions, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task!
 LangChain.Databases.IVectorDatabase.DeleteCollectionAsync(string! collectionName, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.Task!
@@ -90,6 +90,7 @@ static LangChain.Databases.RelevanceScoreFunctions.Cosine(float distance) -> flo
 static LangChain.Databases.RelevanceScoreFunctions.Euclidean(float distance) -> float
 static LangChain.Databases.RelevanceScoreFunctions.Get(LangChain.Databases.DistanceStrategy distanceStrategy) -> System.Func<float, float>!
 static LangChain.Databases.RelevanceScoreFunctions.MaxInnerProduct(float distance) -> float
+static LangChain.Databases.VectorCollection.IsValidJsonKey(string! input) -> bool
 static LangChain.Databases.VectorSearchRequest.implicit operator LangChain.Databases.VectorSearchRequest!(float[]! embedding) -> LangChain.Databases.VectorSearchRequest!
 static LangChain.Databases.VectorSearchRequest.implicit operator LangChain.Databases.VectorSearchRequest!(float[]![]! embeddings) -> LangChain.Databases.VectorSearchRequest!
 static LangChain.Databases.VectorSearchRequest.ToVectorSearchRequest(float[]! embedding) -> LangChain.Databases.VectorSearchRequest!
diff --git a/src/Abstractions/src/VectorCollection.cs b/src/Abstractions/src/VectorCollection.cs
index 5cd8112..45f0b92 100644
--- a/src/Abstractions/src/VectorCollection.cs
+++ b/src/Abstractions/src/VectorCollection.cs
@@ -1,3 +1,5 @@
+using System.Text.RegularExpressions;
+
 namespace LangChain.Databases;
 
 /// <summary>
@@ -20,4 +22,11 @@ public class VectorCollection(
     /// Collection name provided by client.
     /// </summary>
     public string Name { get; set; } = name;
+
+
+    protected static bool IsValidJsonKey(string input)
+    {
+        // Only allow letters, numbers, and underscores
+        return Regex.IsMatch(input, @"^\w+$");
+    }
 }
\ No newline at end of file
diff --git a/src/Chroma/src/ChromaVectorCollection.cs b/src/Chroma/src/ChromaVectorCollection.cs
index 69dfcb3..102b569 100644
--- a/src/Chroma/src/ChromaVectorCollection.cs
+++ b/src/Chroma/src/ChromaVectorCollection.cs
@@ -167,7 +167,7 @@ private static IDictionary<string, object> DeserializeMetadata(MemoryRecordMetad
                ?? new Dictionary<string, object>();
     }
 
-    public Task<List<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
+    public Task<IReadOnlyList<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
     {
         throw new NotSupportedException("Chroma doesn't support collection metadata");
     }
diff --git a/src/Elasticsearch/src/ElasticsearchVectorCollection.cs b/src/Elasticsearch/src/ElasticsearchVectorCollection.cs
index 4091baf..2294058 100644
--- a/src/Elasticsearch/src/ElasticsearchVectorCollection.cs
+++ b/src/Elasticsearch/src/ElasticsearchVectorCollection.cs
@@ -104,7 +104,7 @@ public Task<bool> IsEmptyAsync(CancellationToken cancellationToken = default)
         throw new NotImplementedException();
     }
 
-    Task<List<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
+    Task<IReadOnlyList<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
     {
         throw new NotImplementedException();
     }
diff --git a/src/InMemory/src/InMemoryVectorCollection.cs b/src/InMemory/src/InMemoryVectorCollection.cs
index 2420d0e..93d19f4 100644
--- a/src/InMemory/src/InMemoryVectorCollection.cs
+++ b/src/InMemory/src/InMemoryVectorCollection.cs
@@ -92,7 +92,7 @@ public Task<bool> IsEmptyAsync(CancellationToken cancellationToken = default)
         return Task.FromResult(_vectors.GetValueOrDefault(id));
     }
 
-    public async Task<List<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken = default)
+    public async Task<IReadOnlyList<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken = default)
     {
         filters = filters ?? throw new ArgumentNullException(nameof(filters));
         var filteredVectors = await Task.Run(() => _vectors.Values.Where(vector =>
diff --git a/src/Mongo/src/MongoVectorCollection.cs b/src/Mongo/src/MongoVectorCollection.cs
index 0da1a83..0549048 100644
--- a/src/Mongo/src/MongoVectorCollection.cs
+++ b/src/Mongo/src/MongoVectorCollection.cs
@@ -13,12 +13,14 @@ public class MongoVectorCollection(
 {
     private readonly IMongoCollection<Vector> _mongoCollection = mongoContext.GetCollection<Vector>(name);
 
+    /// <inheritdoc />
     public async Task<IReadOnlyCollection<string>> AddAsync(IReadOnlyCollection<Vector> items, CancellationToken cancellationToken = default)
     {
         await _mongoCollection.InsertManyAsync(items, cancellationToken: cancellationToken).ConfigureAwait(false);
         return items.Select(i => i.Id).ToList();
     }
 
+    /// <inheritdoc />
     public async Task<bool> DeleteAsync(IEnumerable<string> ids, CancellationToken cancellationToken = default)
     {
         var filter = Builders<Vector>.Filter.In(i => i.Id, ids);
@@ -26,6 +28,7 @@ public async Task<bool> DeleteAsync(IEnumerable<string> ids, CancellationToken c
         return result.IsAcknowledged;
     }
 
+    /// <inheritdoc />
     public async Task<Vector?> GetAsync(string id, CancellationToken cancellationToken = default)
     {
         var filter = Builders<Vector>.Filter.Eq(i => i.Id, id);
@@ -33,11 +36,13 @@ public async Task<bool> DeleteAsync(IEnumerable<string> ids, CancellationToken c
         return result.FirstOrDefault(cancellationToken: cancellationToken);
     }
 
+    /// <inheritdoc />
     public async Task<bool> IsEmptyAsync(CancellationToken cancellationToken = default)
     {
         return await _mongoCollection.EstimatedDocumentCountAsync(cancellationToken: cancellationToken).ConfigureAwait(false) == 0;
     }
 
+    /// <inheritdoc />
     public async Task<VectorSearchResponse> SearchAsync(VectorSearchRequest request, VectorSearchSettings? settings = null, CancellationToken cancellationToken = default)
     {
         request = request ?? throw new ArgumentNullException(nameof(request));
@@ -71,7 +76,8 @@ public async Task<VectorSearchResponse> SearchAsync(VectorSearchRequest request,
         };
     }
 
-    public async Task<List<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken = default)
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<Vector>> SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken = default)
     {
         filters = filters ?? throw new ArgumentNullException(nameof(filters));
 
diff --git a/src/OpenSearch/src/OpenSearchVectorCollection.cs b/src/OpenSearch/src/OpenSearchVectorCollection.cs
index 2ea134c..eb9ab13 100644
--- a/src/OpenSearch/src/OpenSearchVectorCollection.cs
+++ b/src/OpenSearch/src/OpenSearchVectorCollection.cs
@@ -134,7 +134,7 @@ public Task<bool> IsEmptyAsync(CancellationToken cancellationToken = default)
         throw new NotImplementedException();
     }
 
-    Task<List<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
+    Task<IReadOnlyList<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
     {
         throw new NotImplementedException();
     }
diff --git a/src/Postgres/src/PostgresVectorCollection.cs b/src/Postgres/src/PostgresVectorCollection.cs
index 8a69a1c..e0b1ba2 100644
--- a/src/Postgres/src/PostgresVectorCollection.cs
+++ b/src/Postgres/src/PostgresVectorCollection.cs
@@ -124,19 +124,33 @@ public Task<bool> IsEmptyAsync(CancellationToken cancellationToken = default)
         throw new NotImplementedException();
     }
 
-    public async Task<List<Vector>> SearchByMetadata(
+    /// <inheritdoc />
+    public async Task<IReadOnlyList<Vector>> SearchByMetadata(
         Dictionary<string, object> filters,
         CancellationToken cancellationToken = default)
     {
         filters = filters ?? throw new ArgumentNullException(nameof(filters));
 
+        foreach (var kvp in filters)
+        {
+            if (string.IsNullOrWhiteSpace(kvp.Key))
+            {
+                throw new ArgumentException("Filter key cannot be null or whitespace.", nameof(filters));
+            }
+            // Add more validation for allowed characters
+            if (!IsValidJsonKey(kvp.Key))
+            {
+                throw new ArgumentException($"Invalid character in filter key: {kvp.Key}", nameof(filters));
+            }
+        }
+
         var records = await client
-            .GetRecordsByMetadataAsync(
-                Name,
-                filters,
-                withEmbeddings: false,
-                cancellationToken: cancellationToken)
-            .ConfigureAwait(false);
+        .GetRecordsByMetadataAsync(
+            Name,
+            filters,
+            withEmbeddings: false,
+            cancellationToken: cancellationToken)
+        .ConfigureAwait(false);
 
         var vectors = records.Select(record => new Vector
         {
diff --git a/src/SemanticKernel/src/SemanticKernelMemoryStoreCollection.cs b/src/SemanticKernel/src/SemanticKernelMemoryStoreCollection.cs
index b3d190f..a89ac69 100644
--- a/src/SemanticKernel/src/SemanticKernelMemoryStoreCollection.cs
+++ b/src/SemanticKernel/src/SemanticKernelMemoryStoreCollection.cs
@@ -76,7 +76,7 @@ public async Task<VectorSearchResponse> SearchAsync(VectorSearchRequest request,
         return new VectorSearchResponse { Items = results.Select(x => new Vector { Text = x.Item1.Metadata.ExternalSourceName }).ToList() };
     }
 
-    Task<List<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
+    Task<IReadOnlyList<Vector>> IVectorCollection.SearchByMetadata(Dictionary<string, object> filters, CancellationToken cancellationToken)
     {
         throw new NotImplementedException();
     }
diff --git a/src/Sqlite/src/SqLiteVectorCollection.cs b/src/Sqlite/src/SqLiteVectorCollection.cs
index b31ce34..f2bfc06 100644
--- a/src/Sqlite/src/SqLiteVectorCollection.cs
+++ b/src/Sqlite/src/SqLiteVectorCollection.cs
@@ -1,7 +1,6 @@
 using Microsoft.Data.Sqlite;
 using System.Globalization;
 using System.Text.Json;
-using System.Text.RegularExpressions;
 
 namespace LangChain.Databases.Sqlite;
 
@@ -190,7 +189,7 @@ public async Task<VectorSearchResponse> SearchAsync(
     }
 
     /// <inheritdoc />
-    public async Task<List<Vector>> SearchByMetadata(
+    public async Task<IReadOnlyList<Vector>> SearchByMetadata(
     Dictionary<string, object> filters,
     CancellationToken cancellationToken = default)
     {
@@ -243,10 +242,4 @@ public async Task<List<Vector>> SearchByMetadata(
 
         return res;
     }
-
-    private static bool IsValidJsonKey(string input)
-    {
-        // Only allow letters, numbers, and underscores
-        return Regex.IsMatch(input, @"^\w+$");
-    }
 }
\ No newline at end of file