Update @github/copilot to 1.0.56-2

dotnet/src/Client.cs

@@ -889,6 +889,7 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
                 config.ClientName,
                 config.ReasoningEffort,
                 config.ReasoningSummary,
+                config.ContextTier,
                 config.Tools?.Select(ToolDefinition.FromAIFunction).ToList(),
                 wireSystemMessage,
                 toolFilter.AvailableTools,
@@ -1083,6 +1084,7 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
                 config.Model,
                 config.ReasoningEffort,
                 config.ReasoningSummary,
+                config.ContextTier,
                 config.Tools?.Select(ToolDefinition.FromAIFunction).ToList(),
                 wireSystemMessage,
                 toolFilter.AvailableTools,
@@ -2274,6 +2276,7 @@ internal record CreateSessionRequest(
         string? ClientName,
         string? ReasoningEffort,
         ReasoningSummary? ReasoningSummary,
+        string? ContextTier,
         IList<ToolDefinition>? Tools,
         SystemMessageConfig? SystemMessage,
         IList<string>? AvailableTools,
@@ -2359,6 +2362,7 @@ internal record ResumeSessionRequest(
         string? Model,
         string? ReasoningEffort,
         ReasoningSummary? ReasoningSummary,
+        string? ContextTier,
         IList<ToolDefinition>? Tools,
         SystemMessageConfig? SystemMessage,
         IList<string>? AvailableTools,

dotnet/src/Types.cs

@@ -2452,6 +2452,7 @@ protected SessionConfigBase(SessionConfigBase? other)
         ManageScheduleEnabled = other.ManageScheduleEnabled;
         ReasoningEffort = other.ReasoningEffort;
         ReasoningSummary = other.ReasoningSummary;
+        ContextTier = other.ContextTier;
         CreateSessionFsProvider = other.CreateSessionFsProvider;
         GitHubToken = other.GitHubToken;
         RemoteSession = other.RemoteSession;
@@ -2494,6 +2495,12 @@ protected SessionConfigBase(SessionConfigBase? other)
     /// </remarks>
     public ReasoningSummary? ReasoningSummary { get; set; }
 
+    /// <summary>
+    /// Context window tier for models that support it.
+    /// Valid values: "default", "long_context".
+    /// </summary>
+    public string? ContextTier { get; set; }
+
     /// <summary>Per-property overrides for model capabilities, deep-merged over runtime defaults.</summary>
     public ModelCapabilitiesOverride? ModelCapabilities { get; set; }
 

dotnet/test/Unit/CloneTests.cs

@@ -69,6 +69,7 @@ public void SessionConfig_Clone_CopiesAllProperties()
             Model = "gpt-4",
             ReasoningEffort = "high",
             ReasoningSummary = ReasoningSummary.Detailed,
+            ContextTier = "long_context",
             ConfigDirectory = "/config",
             AvailableTools = ["tool1", "tool2"],
             ExcludedTools = ["tool3"],
@@ -107,6 +108,7 @@ public void SessionConfig_Clone_CopiesAllProperties()
         Assert.Equal(original.Model, clone.Model);
         Assert.Equal(original.ReasoningEffort, clone.ReasoningEffort);
         Assert.Equal(original.ReasoningSummary, clone.ReasoningSummary);
+        Assert.Equal(original.ContextTier, clone.ContextTier);
         Assert.Equal(original.ConfigDirectory, clone.ConfigDirectory);
         Assert.Equal(original.AvailableTools, clone.AvailableTools);
         Assert.Equal(original.ExcludedTools, clone.ExcludedTools);
@@ -379,6 +381,19 @@ public void ResumeSessionConfig_Clone_CopiesReasoningSummary()
         Assert.Equal(original.ReasoningSummary, clone.ReasoningSummary);
     }
 
+    [Fact]
+    public void ResumeSessionConfig_Clone_CopiesContextTier()
+    {
+        var original = new ResumeSessionConfig
+        {
+            ContextTier = "long_context",
+        };
+
+        var clone = original.Clone();
+
+        Assert.Equal(original.ContextTier, clone.ContextTier);
+    }
+
     [Fact]
     public void ResumeSessionConfig_Clone_CopiesPluginDirectoriesAndLargeOutput()
     {

go/client.go

@@ -605,6 +605,7 @@ func (c *Client) CreateSession(ctx context.Context, config *SessionConfig) (*Ses
 	req.ClientName = config.ClientName
 	req.ReasoningEffort = config.ReasoningEffort
 	req.ReasoningSummary = config.ReasoningSummary
+	req.ContextTier = config.ContextTier
 	req.ConfigDir = config.ConfigDirectory
 	if config.EnableConfigDiscovery {
 		req.EnableConfigDiscovery = Bool(true)
@@ -917,6 +918,7 @@ func (c *Client) ResumeSessionWithOptions(ctx context.Context, sessionID string,
 	req.Model = config.Model
 	req.ReasoningEffort = config.ReasoningEffort
 	req.ReasoningSummary = config.ReasoningSummary
+	req.ContextTier = config.ContextTier
 	systemMessage := c.systemMessageForMode(config.SystemMessage)
 	wireSystemMessage, transformCallbacks := extractTransformCallbacks(systemMessage)
 	req.SystemMessage = wireSystemMessage

go/client_test.go

@@ -434,6 +434,38 @@ func TestSessionRequests_ReasoningSummary(t *testing.T) {
 	})
 }
 
+func TestSessionRequests_ContextTier(t *testing.T) {
+	t.Run("create includes contextTier in JSON when set", func(t *testing.T) {
+		req := createSessionRequest{ContextTier: "long_context"}
+		data, err := json.Marshal(req)
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		var m map[string]any
+		if err := json.Unmarshal(data, &m); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if m["contextTier"] != "long_context" {
+			t.Errorf("Expected contextTier to be 'long_context', got %v", m["contextTier"])
+		}
+	})
+
+	t.Run("resume includes contextTier in JSON when set", func(t *testing.T) {
+		req := resumeSessionRequest{SessionID: "s1", ContextTier: "default"}
+		data, err := json.Marshal(req)
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		var m map[string]any
+		if err := json.Unmarshal(data, &m); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if m["contextTier"] != "default" {
+			t.Errorf("Expected contextTier to be 'default', got %v", m["contextTier"])
+		}
+	})
+}
+
 func TestSessionRequests_PluginDirectoriesAndLargeOutput(t *testing.T) {
 	pluginDirs := []string{"/tmp/plugins/a", "/tmp/plugins/b"}
 	enabled := true

go/types.go

@@ -894,6 +894,9 @@ type SessionConfig struct {
 	// ReasoningSummary mode for models that support configurable reasoning summaries.
 	// Use ReasoningSummaryNone to suppress summary output regardless of whether reasoning is enabled.
 	ReasoningSummary ReasoningSummary
+	// ContextTier pins the session to a context window tier for models that support it.
+	// Valid values: "default", "long_context".
+	ContextTier string
 	// ConfigDirectory overrides the default configuration directory location.
 	// When specified, the session will use this directory for storing config and state.
 	ConfigDirectory string
@@ -1294,6 +1297,9 @@ type ResumeSessionConfig struct {
 	// ReasoningSummary mode for models that support configurable reasoning summaries.
 	// Use ReasoningSummaryNone to suppress summary output regardless of whether reasoning is enabled.
 	ReasoningSummary ReasoningSummary
+	// ContextTier pins the session to a context window tier for models that support it.
+	// Valid values: "default", "long_context".
+	ContextTier string
 	// OnPermissionRequest is an optional handler for permission requests from the server.
 	// When nil, permission requests are surfaced as events and left pending for the
 	// consumer to resolve via pending permission RPCs.
@@ -1654,6 +1660,7 @@ type createSessionRequest struct {
 	ClientName                         string                                 `json:"clientName,omitempty"`
 	ReasoningEffort                    string                                 `json:"reasoningEffort,omitempty"`
 	ReasoningSummary                   ReasoningSummary                       `json:"reasoningSummary,omitempty"`
+	ContextTier                        string                                 `json:"contextTier,omitempty"`
 	Tools                              []Tool                                 `json:"tools,omitempty"`
 	SystemMessage                      *SystemMessageConfig                   `json:"systemMessage,omitempty"`
 	AvailableTools                     []string                               `json:"availableTools"`
@@ -1731,6 +1738,7 @@ type resumeSessionRequest struct {
 	Model                              string                                 `json:"model,omitempty"`
 	ReasoningEffort                    string                                 `json:"reasoningEffort,omitempty"`
 	ReasoningSummary                   ReasoningSummary                       `json:"reasoningSummary,omitempty"`
+	ContextTier                        string                                 `json:"contextTier,omitempty"`
 	Tools                              []Tool                                 `json:"tools,omitempty"`
 	SystemMessage                      *SystemMessageConfig                   `json:"systemMessage,omitempty"`
 	AvailableTools                     []string                               `json:"availableTools"`

java/src/main/java/com/github/copilot/SessionRequestBuilder.java

@@ -107,6 +107,7 @@ static CreateSessionRequest buildCreateRequest(SessionConfig config, String sess
         request.setClientName(config.getClientName());
         request.setReasoningEffort(config.getReasoningEffort());
         request.setReasoningSummary(config.getReasoningSummary());
+        request.setContextTier(config.getContextTier());
         request.setTools(config.getTools());
         request.setSystemMessage(config.getSystemMessage());
         request.setAvailableTools(config.getAvailableTools());
@@ -217,6 +218,7 @@ static ResumeSessionRequest buildResumeRequest(String sessionId, ResumeSessionCo
         request.setClientName(config.getClientName());
         request.setReasoningEffort(config.getReasoningEffort());
         request.setReasoningSummary(config.getReasoningSummary());
+        request.setContextTier(config.getContextTier());
         request.setTools(config.getTools());
         request.setSystemMessage(config.getSystemMessage());
         request.setAvailableTools(config.getAvailableTools());

java/src/main/java/com/github/copilot/rpc/CreateSessionRequest.java

@@ -39,6 +39,9 @@ public final class CreateSessionRequest {
     @JsonProperty("reasoningSummary")
     private String reasoningSummary;
 
+    @JsonProperty("contextTier")
+    private String contextTier;
+
     @JsonProperty("tools")
     private List<ToolDefinition> tools;
 
@@ -234,6 +237,16 @@ public void setReasoningSummary(String reasoningSummary) {
         this.reasoningSummary = reasoningSummary;
     }
 
+    /** Gets the context window tier. @return the context window tier */
+    public String getContextTier() {
+        return contextTier;
+    }
+
+    /** Sets the context window tier. @param contextTier the context window tier */
+    public void setContextTier(String contextTier) {
+        this.contextTier = contextTier;
+    }
+
     /** Gets the tools. @return the tool definitions */
     public List<ToolDefinition> getTools() {
         return tools == null ? null : Collections.unmodifiableList(tools);