Expose enableOnDemandInstructionDiscovery across all SDK SessionConfig types

dotnet/src/Client.cs

@@ -629,6 +629,7 @@ public async Task<CopilotSession> CreateSessionAsync(SessionConfig config, Cance
                 config.Agent,
                 config.ConfigDir,
                 config.EnableConfigDiscovery,
+                config.EnableOnDemandInstructionDiscovery,
                 config.SkillDirectories,
                 config.DisabledSkills,
                 config.InfiniteSessions,
@@ -780,6 +781,7 @@ public async Task<CopilotSession> ResumeSessionAsync(string sessionId, ResumeSes
                 config.WorkingDirectory,
                 config.ConfigDir,
                 config.EnableConfigDiscovery,
+                config.EnableOnDemandInstructionDiscovery,
                 config.DisableResume is true ? true : null,
                 config.Streaming is true ? true : null,
                 config.IncludeSubAgentStreamingEvents,
@@ -2020,6 +2022,7 @@ internal record CreateSessionRequest(
         string? Agent,
         string? ConfigDir,
         bool? EnableConfigDiscovery,
+        bool? EnableOnDemandInstructionDiscovery,
         IList<string>? SkillDirectories,
         IList<string>? DisabledSkills,
         InfiniteSessionConfig? InfiniteSessions,
@@ -2074,6 +2077,7 @@ internal record ResumeSessionRequest(
         string? WorkingDirectory,
         string? ConfigDir,
         bool? EnableConfigDiscovery,
+        bool? EnableOnDemandInstructionDiscovery,
         bool? DisableResume,
         bool? Streaming,
         bool? IncludeSubAgentStreamingEvents,

dotnet/src/Types.cs

@@ -2058,6 +2058,7 @@ protected SessionConfig(SessionConfig? other)
         Agent = other.Agent;
         DisabledSkills = other.DisabledSkills is not null ? [.. other.DisabledSkills] : null;
         EnableConfigDiscovery = other.EnableConfigDiscovery;
+        EnableOnDemandInstructionDiscovery = other.EnableOnDemandInstructionDiscovery;
         ExcludedTools = other.ExcludedTools is not null ? [.. other.ExcludedTools] : null;
         Hooks = other.Hooks;
         InfiniteSessions = other.InfiniteSessions;
@@ -2138,6 +2139,25 @@ protected SessionConfig(SessionConfig? other)
     /// </summary>
     public bool? EnableConfigDiscovery { get; set; }
 
+    /// <summary>
+    /// When <see langword="true"/>, requests on-demand discovery of custom instruction
+    /// files after the agent successfully reads or views files. Discovered instruction
+    /// files are treated as model instructions and may influence agent behavior.
+    /// <para>
+    /// Runtime-gated: only takes effect when custom instructions are enabled and the
+    /// connected runtime supports and enables on-demand custom instruction discovery.
+    /// Otherwise the runtime accepts the option but performs no on-demand instruction
+    /// discovery.
+    /// </para>
+    /// <para>
+    /// Security: enable only for trusted repositories or workspaces. Discovered
+    /// instruction files may be stored or replayed with session history. Do not enable
+    /// for untrusted content, CI jobs processing untrusted forks, or directories
+    /// writable by untrusted users or processes.
+    /// </para>
+    /// </summary>
+    public bool? EnableOnDemandInstructionDiscovery { get; set; }
+
     /// <summary>
     /// Custom tool declarations available to the language model during the session.
     /// Declarations backed by an <see cref="AIFunction"/> are invoked automatically; declarations without one
@@ -2368,6 +2388,7 @@ protected ResumeSessionConfig(ResumeSessionConfig? other)
         DisabledSkills = other.DisabledSkills is not null ? [.. other.DisabledSkills] : null;
         DisableResume = other.DisableResume;
         EnableConfigDiscovery = other.EnableConfigDiscovery;
+        EnableOnDemandInstructionDiscovery = other.EnableOnDemandInstructionDiscovery;
         ContinuePendingWork = other.ContinuePendingWork;
         ExcludedTools = other.ExcludedTools is not null ? [.. other.ExcludedTools] : null;
         Hooks = other.Hooks;
@@ -2528,6 +2549,17 @@ protected ResumeSessionConfig(ResumeSessionConfig? other)
     /// </summary>
     public bool? EnableConfigDiscovery { get; set; }
 
+    /// <summary>
+    /// When <see langword="true"/>, requests on-demand discovery of custom instruction
+    /// files after the agent successfully reads or views files. See
+    /// <see cref="SessionConfig.EnableOnDemandInstructionDiscovery"/> for details.
+    /// <para>
+    /// For resumed sessions, omitting this option leaves the existing session setting
+    /// unchanged; set <see langword="false"/> to disable future on-demand discovery.
+    /// </para>
+    /// </summary>
+    public bool? EnableOnDemandInstructionDiscovery { get; set; }
+
     /// <summary>
     /// When true, the session.resume event is not emitted.
     /// Default: false (resume event is emitted).

dotnet/test/Unit/CloneTests.cs

@@ -92,6 +92,7 @@ public void SessionConfig_Clone_CopiesAllProperties()
             WorkingDirectory = "/workspace",
             Streaming = true,
             EnableSessionTelemetry = false,
+            EnableOnDemandInstructionDiscovery = true,
             IncludeSubAgentStreamingEvents = false,
             McpServers = new Dictionary<string, McpServerConfig> { ["server1"] = new McpStdioServerConfig { Command = "echo" } },
             CustomAgents = [new CustomAgentConfig { Name = "agent1", Model = "claude-haiku-4.5" }],
@@ -125,6 +126,7 @@ public void SessionConfig_Clone_CopiesAllProperties()
         Assert.Equal(original.WorkingDirectory, clone.WorkingDirectory);
         Assert.Equal(original.Streaming, clone.Streaming);
         Assert.Equal(original.EnableSessionTelemetry, clone.EnableSessionTelemetry);
+        Assert.Equal(original.EnableOnDemandInstructionDiscovery, clone.EnableOnDemandInstructionDiscovery);
         Assert.Equal(original.IncludeSubAgentStreamingEvents, clone.IncludeSubAgentStreamingEvents);
         Assert.Equal(original.McpServers.Count, clone.McpServers!.Count);
         Assert.Equal(original.CustomAgents.Count, clone.CustomAgents!.Count);
@@ -403,4 +405,50 @@ public void ResumeSessionConfig_Clone_PreservesEnableSessionTelemetryDefault()
 
         Assert.Null(clone.EnableSessionTelemetry);
     }
+
+    [Fact]
+    public void SessionConfig_Clone_CopiesEnableOnDemandInstructionDiscovery()
+    {
+        var original = new SessionConfig
+        {
+            EnableOnDemandInstructionDiscovery = false,
+        };
+
+        var clone = original.Clone();
+
+        Assert.False(clone.EnableOnDemandInstructionDiscovery);
+    }
+
+    [Fact]
+    public void ResumeSessionConfig_Clone_CopiesEnableOnDemandInstructionDiscovery()
+    {
+        var original = new ResumeSessionConfig
+        {
+            EnableOnDemandInstructionDiscovery = true,
+        };
+
+        var clone = original.Clone();
+
+        Assert.True(clone.EnableOnDemandInstructionDiscovery);
+    }
+
+    [Fact]
+    public void SessionConfig_Clone_PreservesEnableOnDemandInstructionDiscoveryDefault()
+    {
+        var original = new SessionConfig();
+
+        var clone = original.Clone();
+
+        Assert.Null(clone.EnableOnDemandInstructionDiscovery);
+    }
+
+    [Fact]
+    public void ResumeSessionConfig_Clone_PreservesEnableOnDemandInstructionDiscoveryDefault()
+    {
+        var original = new ResumeSessionConfig();
+
+        var clone = original.Clone();
+
+        Assert.Null(clone.EnableOnDemandInstructionDiscovery);
+    }
 }

dotnet/test/Unit/SerializationTests.cs

@@ -203,6 +203,60 @@ public void ResumeSessionRequest_CanSerializeEnableSessionTelemetry_WithSdkOptio
         Assert.False(root.GetProperty("enableSessionTelemetry").GetBoolean());
     }
 
+    [Fact]
+    public void CreateSessionRequest_CanSerializeEnableOnDemandInstructionDiscovery_WithSdkOptions()
+    {
+        var options = GetSerializerOptions();
+        var requestType = GetNestedType(typeof(CopilotClient), "CreateSessionRequest");
+
+        var requestTrue = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"),
+            ("EnableOnDemandInstructionDiscovery", true));
+        var rootTrue = JsonDocument.Parse(JsonSerializer.Serialize(requestTrue, requestType, options)).RootElement;
+        Assert.True(rootTrue.GetProperty("enableOnDemandInstructionDiscovery").GetBoolean());
+
+        var requestFalse = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"),
+            ("EnableOnDemandInstructionDiscovery", false));
+        var rootFalse = JsonDocument.Parse(JsonSerializer.Serialize(requestFalse, requestType, options)).RootElement;
+        Assert.False(rootFalse.GetProperty("enableOnDemandInstructionDiscovery").GetBoolean());
+
+        var requestOmitted = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"));
+        var rootOmitted = JsonDocument.Parse(JsonSerializer.Serialize(requestOmitted, requestType, options)).RootElement;
+        Assert.False(rootOmitted.TryGetProperty("enableOnDemandInstructionDiscovery", out _));
+    }
+
+    [Fact]
+    public void ResumeSessionRequest_CanSerializeEnableOnDemandInstructionDiscovery_WithSdkOptions()
+    {
+        var options = GetSerializerOptions();
+        var requestType = GetNestedType(typeof(CopilotClient), "ResumeSessionRequest");
+
+        var requestTrue = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"),
+            ("EnableOnDemandInstructionDiscovery", true));
+        var rootTrue = JsonDocument.Parse(JsonSerializer.Serialize(requestTrue, requestType, options)).RootElement;
+        Assert.True(rootTrue.GetProperty("enableOnDemandInstructionDiscovery").GetBoolean());
+
+        var requestFalse = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"),
+            ("EnableOnDemandInstructionDiscovery", false));
+        var rootFalse = JsonDocument.Parse(JsonSerializer.Serialize(requestFalse, requestType, options)).RootElement;
+        Assert.False(rootFalse.GetProperty("enableOnDemandInstructionDiscovery").GetBoolean());
+
+        var requestOmitted = CreateInternalRequest(
+            requestType,
+            ("SessionId", "session-id"));
+        var rootOmitted = JsonDocument.Parse(JsonSerializer.Serialize(requestOmitted, requestType, options)).RootElement;
+        Assert.False(rootOmitted.TryGetProperty("enableOnDemandInstructionDiscovery", out _));
+    }
+
     [Fact]
     public void ResumeSessionRequest_CanSerializeModeRequestFlags_WithSdkOptions()
     {

go/client.go

@@ -625,6 +625,7 @@ func (c *Client) CreateSession(ctx context.Context, config *SessionConfig) (*Ses
 	if config.EnableConfigDiscovery {
 		req.EnableConfigDiscovery = Bool(true)
 	}
+	req.EnableOnDemandInstructionDiscovery = config.EnableOnDemandInstructionDiscovery
 	req.Tools = config.Tools
 	wireSystemMessage, transformCallbacks := extractTransformCallbacks(config.SystemMessage)
 	req.SystemMessage = wireSystemMessage
@@ -831,6 +832,7 @@ func (c *Client) ResumeSessionWithOptions(ctx context.Context, sessionID string,
 	if config.EnableConfigDiscovery {
 		req.EnableConfigDiscovery = Bool(true)
 	}
+	req.EnableOnDemandInstructionDiscovery = config.EnableOnDemandInstructionDiscovery
 	if config.DisableResume {
 		req.DisableResume = Bool(true)
 	}

go/client_test.go

@@ -1318,6 +1318,100 @@ func TestResumeSessionRequest_IncludeSubAgentStreamingEvents(t *testing.T) {
 	})
 }
 
+func TestCreateSessionRequest_EnableOnDemandInstructionDiscovery(t *testing.T) {
+	t.Run("forwards explicit true", func(t *testing.T) {
+		req := createSessionRequest{
+			EnableOnDemandInstructionDiscovery: Bool(true),
+		}
+		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["enableOnDemandInstructionDiscovery"] != true {
+			t.Errorf("Expected enableOnDemandInstructionDiscovery to be true, got %v", m["enableOnDemandInstructionDiscovery"])
+		}
+	})
+
+	t.Run("preserves explicit false", func(t *testing.T) {
+		req := createSessionRequest{
+			EnableOnDemandInstructionDiscovery: Bool(false),
+		}
+		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["enableOnDemandInstructionDiscovery"] != false {
+			t.Errorf("Expected enableOnDemandInstructionDiscovery to be false, got %v", m["enableOnDemandInstructionDiscovery"])
+		}
+	})
+
+	t.Run("omits enableOnDemandInstructionDiscovery when not set", func(t *testing.T) {
+		req := createSessionRequest{}
+		data, _ := json.Marshal(req)
+		var m map[string]any
+		json.Unmarshal(data, &m)
+		if _, ok := m["enableOnDemandInstructionDiscovery"]; ok {
+			t.Error("Expected enableOnDemandInstructionDiscovery to be omitted when not set")
+		}
+	})
+}
+
+func TestResumeSessionRequest_EnableOnDemandInstructionDiscovery(t *testing.T) {
+	t.Run("forwards explicit true", func(t *testing.T) {
+		req := resumeSessionRequest{
+			SessionID:                          "s1",
+			EnableOnDemandInstructionDiscovery: Bool(true),
+		}
+		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["enableOnDemandInstructionDiscovery"] != true {
+			t.Errorf("Expected enableOnDemandInstructionDiscovery to be true, got %v", m["enableOnDemandInstructionDiscovery"])
+		}
+	})
+
+	t.Run("preserves explicit false", func(t *testing.T) {
+		req := resumeSessionRequest{
+			SessionID:                          "s1",
+			EnableOnDemandInstructionDiscovery: Bool(false),
+		}
+		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["enableOnDemandInstructionDiscovery"] != false {
+			t.Errorf("Expected enableOnDemandInstructionDiscovery to be false, got %v", m["enableOnDemandInstructionDiscovery"])
+		}
+	})
+
+	t.Run("omits enableOnDemandInstructionDiscovery when not set", func(t *testing.T) {
+		req := resumeSessionRequest{SessionID: "s1"}
+		data, _ := json.Marshal(req)
+		var m map[string]any
+		json.Unmarshal(data, &m)
+		if _, ok := m["enableOnDemandInstructionDiscovery"]; ok {
+			t.Error("Expected enableOnDemandInstructionDiscovery to be omitted when not set")
+		}
+	})
+}
+
 func TestCreateSessionResponse_Capabilities(t *testing.T) {
 	t.Run("reads capabilities from session.create response", func(t *testing.T) {
 		responseJSON := `{"sessionId":"s1","workspacePath":"/tmp","capabilities":{"ui":{"elicitation":true}}}`

go/internal/e2e/client_options_e2e_test.go

@@ -198,9 +198,10 @@ func TestClientOptionsE2E(t *testing.T) {
 		}
 
 		session, err := client.CreateSession(t.Context(), &copilot.SessionConfig{
-			EnableConfigDiscovery:          true,
-			IncludeSubAgentStreamingEvents: copilot.Bool(false),
-			OnPermissionRequest:            copilot.PermissionHandler.ApproveAll,
+			EnableConfigDiscovery:              true,
+			EnableOnDemandInstructionDiscovery: copilot.Bool(true),
+			IncludeSubAgentStreamingEvents:     copilot.Bool(false),
+			OnPermissionRequest:                copilot.PermissionHandler.ApproveAll,
 		})
 		if err != nil {
 			t.Fatalf("CreateSession failed: %v", err)
@@ -225,6 +226,9 @@ func TestClientOptionsE2E(t *testing.T) {
 		if v, ok := params["enableConfigDiscovery"].(bool); !ok || v != true {
 			t.Errorf("Expected session.create.params.enableConfigDiscovery=true, got %v", params["enableConfigDiscovery"])
 		}
+		if v, ok := params["enableOnDemandInstructionDiscovery"].(bool); !ok || v != true {
+			t.Errorf("Expected session.create.params.enableOnDemandInstructionDiscovery=true, got %v", params["enableOnDemandInstructionDiscovery"])
+		}
 		if v, ok := params["includeSubAgentStreamingEvents"].(bool); !ok || v != false {
 			t.Errorf("Expected session.create.params.includeSubAgentStreamingEvents=false, got %v", params["includeSubAgentStreamingEvents"])
 		}