diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/AgentSessionStore.cs b/dotnet/src/Microsoft.Agents.AI.Abstractions/AgentSessionStore.cs
index d4f4a74d22d..0f2c8ac1a5d 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/AgentSessionStore.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/AgentSessionStore.cs
@@ -27,11 +27,34 @@ public abstract class AgentSessionStore
     /// <param name="session">The session to save.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
     /// <returns>A task that represents the asynchronous save operation.</returns>
+#pragma warning disable RS0026 // Overloaded by a sessionId-based convenience method.
     public abstract ValueTask SaveSessionAsync(
         AIAgent agent,
         AgentSessionStoreKey key,
         AgentSession session,
         CancellationToken cancellationToken = default);
+#pragma warning restore RS0026
+
+    /// <summary>
+    /// Saves an agent session to persistent storage using a session identifier without partitions.
+    /// </summary>
+    /// <param name="agent">The agent that owns this session.</param>
+    /// <param name="sessionId">The logical session identifier.</param>
+    /// <param name="session">The session to save.</param>
+    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous save operation.</returns>
+    /// <remarks>
+    /// This is a convenience overload that creates an <see cref="AgentSessionStoreKey"/> from
+    /// <paramref name="sessionId"/> and calls <see cref="SaveSessionAsync(AIAgent, AgentSessionStoreKey, AgentSession, CancellationToken)"/>.
+    /// </remarks>
+#pragma warning disable RS0026 // Convenience overload that mirrors the AgentSessionStoreKey-based method.
+    public ValueTask SaveSessionAsync(
+        AIAgent agent,
+        string sessionId,
+        AgentSession session,
+        CancellationToken cancellationToken = default)
+        => this.SaveSessionAsync(agent, new AgentSessionStoreKey(sessionId), session, cancellationToken);
+#pragma warning restore RS0026
 
     /// <summary>
     /// Retrieves an agent session from persistent storage, or <see langword="null"/> when no session is stored
@@ -50,10 +73,35 @@ public abstract ValueTask SaveSessionAsync(
     /// branches observing one another's changes or modifying the stored state. Implementations that cache a
     /// live session must return an independent copy rather than the shared instance.
     /// </remarks>
+#pragma warning disable RS0026 // Overloaded by a sessionId-based convenience method.
     public abstract ValueTask<AgentSession?> GetSessionAsync(
         AIAgent agent,
         AgentSessionStoreKey key,
         CancellationToken cancellationToken = default);
+#pragma warning restore RS0026
+
+    /// <summary>
+    /// Retrieves an agent session from persistent storage using a session identifier without partitions,
+    /// or <see langword="null"/> when no session is stored for the given identifier.
+    /// </summary>
+    /// <param name="agent">The agent that owns this session.</param>
+    /// <param name="sessionId">The logical session identifier.</param>
+    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
+    /// <returns>
+    /// A task whose result contains the restored session, or <see langword="null"/> when nothing is stored for
+    /// the given identifier. This method never creates a session.
+    /// </returns>
+    /// <remarks>
+    /// This is a convenience overload that creates an <see cref="AgentSessionStoreKey"/> from
+    /// <paramref name="sessionId"/> and calls <see cref="GetSessionAsync(AIAgent, AgentSessionStoreKey, CancellationToken)"/>.
+    /// </remarks>
+#pragma warning disable RS0026 // Convenience overload that mirrors the AgentSessionStoreKey-based method.
+    public ValueTask<AgentSession?> GetSessionAsync(
+        AIAgent agent,
+        string sessionId,
+        CancellationToken cancellationToken = default)
+        => this.GetSessionAsync(agent, new AgentSessionStoreKey(sessionId), cancellationToken);
+#pragma warning restore RS0026
 
     /// <summary>
     /// Retrieves the stored session for the given identifiers, or creates a new one when none is stored.
@@ -63,10 +111,12 @@ public abstract ValueTask SaveSessionAsync(
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
     /// <returns>A task whose result is always a usable session.</returns>
     /// <remarks>
-    /// The default implementation calls <see cref="GetSessionAsync"/> and creates a session through
-    /// <see cref="AIAgent.CreateSessionAsync"/> only when the lookup returns <see langword="null"/>.
-    /// Implementations that override <see cref="GetSessionAsync"/> receive this behavior automatically.
+    /// The default implementation calls <see cref="GetSessionAsync(AIAgent, AgentSessionStoreKey, CancellationToken)"/>
+    /// and creates a session through <see cref="AIAgent.CreateSessionAsync"/> only when the lookup returns
+    /// <see langword="null"/>. Implementations that override
+    /// <see cref="GetSessionAsync(AIAgent, AgentSessionStoreKey, CancellationToken)"/> receive this behavior automatically.
     /// </remarks>
+#pragma warning disable RS0026 // Overloaded by a sessionId-based convenience method.
     public virtual async ValueTask<AgentSession> GetOrCreateSessionAsync(
         AIAgent agent,
         AgentSessionStoreKey key,
@@ -77,6 +127,27 @@ public virtual async ValueTask<AgentSession> GetOrCreateSessionAsync(
         return await this.GetSessionAsync(agent, key, cancellationToken).ConfigureAwait(false)
             ?? await agent.CreateSessionAsync(cancellationToken).ConfigureAwait(false);
     }
+#pragma warning restore RS0026
+
+    /// <summary>
+    /// Retrieves the stored session for the given session identifier without partitions, or creates a new one
+    /// when none is stored.
+    /// </summary>
+    /// <param name="agent">The agent that owns this session.</param>
+    /// <param name="sessionId">The logical session identifier.</param>
+    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
+    /// <returns>A task whose result is always a usable session.</returns>
+    /// <remarks>
+    /// This is a convenience overload that creates an <see cref="AgentSessionStoreKey"/> from
+    /// <paramref name="sessionId"/> and calls <see cref="GetOrCreateSessionAsync(AIAgent, AgentSessionStoreKey, CancellationToken)"/>.
+    /// </remarks>
+#pragma warning disable RS0026 // Convenience overload that mirrors the AgentSessionStoreKey-based method.
+    public ValueTask<AgentSession> GetOrCreateSessionAsync(
+        AIAgent agent,
+        string sessionId,
+        CancellationToken cancellationToken = default)
+        => this.GetOrCreateSessionAsync(agent, new AgentSessionStoreKey(sessionId), cancellationToken);
+#pragma warning restore RS0026
 
     /// <summary>
     /// Deletes a stored agent session, if present.
@@ -88,10 +159,31 @@ public virtual async ValueTask<AgentSession> GetOrCreateSessionAsync(
     /// <remarks>
     /// Implementations delete the session and treat a missing session as a no-op.
     /// </remarks>
+#pragma warning disable RS0026 // Overloaded by a sessionId-based convenience method.
     public abstract ValueTask DeleteSessionAsync(
         AIAgent agent,
         AgentSessionStoreKey key,
         CancellationToken cancellationToken = default);
+#pragma warning restore RS0026
+
+    /// <summary>
+    /// Deletes a stored agent session identified by a session identifier without partitions, if present.
+    /// </summary>
+    /// <param name="agent">The agent that owns this session.</param>
+    /// <param name="sessionId">The logical session identifier.</param>
+    /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests.</param>
+    /// <returns>A task that represents the asynchronous delete operation.</returns>
+    /// <remarks>
+    /// This is a convenience overload that creates an <see cref="AgentSessionStoreKey"/> from
+    /// <paramref name="sessionId"/> and calls <see cref="DeleteSessionAsync(AIAgent, AgentSessionStoreKey, CancellationToken)"/>.
+    /// </remarks>
+#pragma warning disable RS0026 // Convenience overload that mirrors the AgentSessionStoreKey-based method.
+    public ValueTask DeleteSessionAsync(
+        AIAgent agent,
+        string sessionId,
+        CancellationToken cancellationToken = default)
+        => this.DeleteSessionAsync(agent, new AgentSessionStoreKey(sessionId), cancellationToken);
+#pragma warning restore RS0026
 
     /// <summary>Asks the store for an object of the specified type.</summary>
     /// <param name="serviceType">The type of object being requested.</param>
diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net10.0/PublicAPI.Unshipped.txt b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net10.0/PublicAPI.Unshipped.txt
index 085b5279485..e68014631c9 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net10.0/PublicAPI.Unshipped.txt
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net10.0/PublicAPI.Unshipped.txt
@@ -7,6 +7,10 @@
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]virtual Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession?>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.AgentSessionStoreKey(string! sessionId, System.Collections.Generic.IReadOnlyDictionary<string!, string!>? partitions = null) -> void
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.Equals(Microsoft.Agents.AI.AgentSessionStoreKey? other) -> bool
diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net472/PublicAPI.Unshipped.txt b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net472/PublicAPI.Unshipped.txt
index 085b5279485..e68014631c9 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net472/PublicAPI.Unshipped.txt
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net472/PublicAPI.Unshipped.txt
@@ -7,6 +7,10 @@
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]virtual Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession?>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.AgentSessionStoreKey(string! sessionId, System.Collections.Generic.IReadOnlyDictionary<string!, string!>? partitions = null) -> void
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.Equals(Microsoft.Agents.AI.AgentSessionStoreKey? other) -> bool
diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net8.0/PublicAPI.Unshipped.txt b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net8.0/PublicAPI.Unshipped.txt
index 085b5279485..e68014631c9 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net8.0/PublicAPI.Unshipped.txt
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net8.0/PublicAPI.Unshipped.txt
@@ -7,6 +7,10 @@
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]virtual Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession?>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.AgentSessionStoreKey(string! sessionId, System.Collections.Generic.IReadOnlyDictionary<string!, string!>? partitions = null) -> void
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.Equals(Microsoft.Agents.AI.AgentSessionStoreKey? other) -> bool
diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net9.0/PublicAPI.Unshipped.txt b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net9.0/PublicAPI.Unshipped.txt
index 085b5279485..e68014631c9 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net9.0/PublicAPI.Unshipped.txt
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/net9.0/PublicAPI.Unshipped.txt
@@ -7,6 +7,10 @@
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]virtual Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession?>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.AgentSessionStoreKey(string! sessionId, System.Collections.Generic.IReadOnlyDictionary<string!, string!>? partitions = null) -> void
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.Equals(Microsoft.Agents.AI.AgentSessionStoreKey? other) -> bool
diff --git a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt
index 085b5279485..e68014631c9 100644
--- a/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt
+++ b/dotnet/src/Microsoft.Agents.AI.Abstractions/PublicAPI/netstandard2.0/PublicAPI.Unshipped.txt
@@ -7,6 +7,10 @@
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]abstract Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
 [MAAI001]virtual Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, Microsoft.Agents.AI.AgentSessionStoreKey! key, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession?>
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.SaveSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, Microsoft.Agents.AI.AgentSession! session, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.DeleteSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask
+[MAAI001]Microsoft.Agents.AI.AgentSessionStore.GetOrCreateSessionAsync(Microsoft.Agents.AI.AIAgent! agent, string! sessionId, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> System.Threading.Tasks.ValueTask<Microsoft.Agents.AI.AgentSession!>
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.AgentSessionStoreKey(string! sessionId, System.Collections.Generic.IReadOnlyDictionary<string!, string!>? partitions = null) -> void
 [MAAI001]Microsoft.Agents.AI.AgentSessionStoreKey.Equals(Microsoft.Agents.AI.AgentSessionStoreKey? other) -> bool
diff --git a/dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentSessionStoreTests.cs b/dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentSessionStoreTests.cs
index d113eb9110c..f3ce91ebdf3 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentSessionStoreTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Abstractions.UnitTests/AgentSessionStoreTests.cs
@@ -120,6 +120,108 @@ await Assert.ThrowsAsync<ArgumentNullException>(
             () => store.GetOrCreateSessionAsync(null!, new AgentSessionStoreKey("conversation-1")).AsTask());
     }
 
+    [Fact]
+    public async Task GetSessionAsync_SessionIdOverload_ForwardsKeyWithoutPartitionsAsync()
+    {
+        // Arrange
+        var storedSession = new TestAgentSession();
+        var agent = new Mock<AIAgent>().Object;
+        using var cts = new CancellationTokenSource();
+        var store = new Mock<AgentSessionStore>();
+        store.Setup(s => s.GetSessionAsync(agent, It.IsAny<AgentSessionStoreKey>(), cts.Token))
+            .ReturnsAsync(storedSession);
+
+        // Act
+        AgentSession? session = await store.Object.GetSessionAsync(agent, "conversation-1", cts.Token);
+
+        // Assert
+        Assert.Same(storedSession, session);
+        store.Verify(
+            s => s.GetSessionAsync(agent, It.Is<AgentSessionStoreKey>(k => IsUnpartitionedKey(k, "conversation-1")), cts.Token),
+            Times.Once);
+    }
+
+    [Fact]
+    public async Task SaveSessionAsync_SessionIdOverload_ForwardsKeyWithoutPartitionsAsync()
+    {
+        // Arrange
+        var session = new TestAgentSession();
+        var agent = new Mock<AIAgent>().Object;
+        using var cts = new CancellationTokenSource();
+        var store = new Mock<AgentSessionStore>();
+        store.Setup(s => s.SaveSessionAsync(agent, It.IsAny<AgentSessionStoreKey>(), session, cts.Token))
+            .Returns(default(ValueTask));
+
+        // Act
+        await store.Object.SaveSessionAsync(agent, "conversation-1", session, cts.Token);
+
+        // Assert
+        store.Verify(
+            s => s.SaveSessionAsync(agent, It.Is<AgentSessionStoreKey>(k => IsUnpartitionedKey(k, "conversation-1")), session, cts.Token),
+            Times.Once);
+    }
+
+    [Fact]
+    public async Task GetOrCreateSessionAsync_SessionIdOverload_ForwardsKeyWithoutPartitionsAsync()
+    {
+        // Arrange
+        var storedSession = new TestAgentSession();
+        var agent = new Mock<AIAgent>().Object;
+        using var cts = new CancellationTokenSource();
+        var store = new Mock<AgentSessionStore>();
+        store.Setup(s => s.GetOrCreateSessionAsync(agent, It.IsAny<AgentSessionStoreKey>(), cts.Token))
+            .ReturnsAsync(storedSession);
+
+        // Act
+        AgentSession session = await store.Object.GetOrCreateSessionAsync(agent, "conversation-1", cts.Token);
+
+        // Assert
+        Assert.Same(storedSession, session);
+        store.Verify(
+            s => s.GetOrCreateSessionAsync(agent, It.Is<AgentSessionStoreKey>(k => IsUnpartitionedKey(k, "conversation-1")), cts.Token),
+            Times.Once);
+    }
+
+    [Fact]
+    public async Task DeleteSessionAsync_SessionIdOverload_ForwardsKeyWithoutPartitionsAsync()
+    {
+        // Arrange
+        var agent = new Mock<AIAgent>().Object;
+        using var cts = new CancellationTokenSource();
+        var store = new Mock<AgentSessionStore>();
+        store.Setup(s => s.DeleteSessionAsync(agent, It.IsAny<AgentSessionStoreKey>(), cts.Token))
+            .Returns(default(ValueTask));
+
+        // Act
+        await store.Object.DeleteSessionAsync(agent, "conversation-1", cts.Token);
+
+        // Assert
+        store.Verify(
+            s => s.DeleteSessionAsync(agent, It.Is<AgentSessionStoreKey>(k => IsUnpartitionedKey(k, "conversation-1")), cts.Token),
+            Times.Once);
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    public async Task SessionIdOverloads_InvalidSessionId_ThrowAsync(string? sessionId)
+    {
+        // Arrange
+        var store = new TestAgentSessionStore(session: null);
+        var agent = new Mock<AIAgent>().Object;
+        var session = new TestAgentSession();
+
+        // Act and assert
+        await Assert.ThrowsAnyAsync<ArgumentException>(() => store.GetSessionAsync(agent, sessionId!).AsTask());
+        await Assert.ThrowsAnyAsync<ArgumentException>(() => store.SaveSessionAsync(agent, sessionId!, session).AsTask());
+        await Assert.ThrowsAnyAsync<ArgumentException>(() => store.GetOrCreateSessionAsync(agent, sessionId!).AsTask());
+        await Assert.ThrowsAnyAsync<ArgumentException>(() => store.DeleteSessionAsync(agent, sessionId!).AsTask());
+    }
+
+    private static bool IsUnpartitionedKey(AgentSessionStoreKey key, string sessionId)
+        => string.Equals(key.SessionId, sessionId, StringComparison.Ordinal) && key.Partitions is null;
+
     private sealed class TestAgentSessionStore(AgentSession? session) : AgentSessionStore
     {
         public AgentSessionStoreKey? LastKey { get; private set; }