feat: expose clientName in SDK session metadata

dotnet/src/Types.cs

@@ -2736,6 +2736,10 @@ public sealed class SessionMetadata
     /// </summary>
     public string? Summary { get; set; }
     /// <summary>
+    /// Identifier of the client driving the session.
+    /// </summary>
+    public string? ClientName { get; set; }
+    /// <summary>
     /// Whether the session is running on a remote server.
     /// </summary>
     public bool IsRemote { get; set; }

dotnet/test/Unit/SerializationTests.cs

@@ -171,6 +171,30 @@ public void ResumeSessionRequest_CanSerializeInstructionDirectories_WithSdkOptio
         Assert.Equal("C:\\resume-instructions", root.GetProperty("instructionDirectories")[0].GetString());
     }
 
+    [Fact]
+    public void SessionMetadata_CanRoundTripClientName_WithSdkOptions()
+    {
+        var options = GetSerializerOptions();
+        var original = new SessionMetadata
+        {
+            SessionId = "session-1",
+            StartTime = DateTimeOffset.Parse("2025-01-01T00:00:00Z"),
+            ModifiedTime = DateTimeOffset.Parse("2025-01-01T01:00:00Z"),
+            Summary = "loaded session",
+            ClientName = "my-app",
+            IsRemote = false
+        };
+
+        var json = JsonSerializer.Serialize(original, options);
+        using var document = JsonDocument.Parse(json);
+        var root = document.RootElement;
+        Assert.Equal("my-app", root.GetProperty("clientName").GetString());
+
+        var deserialized = JsonSerializer.Deserialize<SessionMetadata>(json, options);
+        Assert.NotNull(deserialized);
+        Assert.Equal("my-app", deserialized.ClientName);
+    }
+
     [Fact]
     public void CreateSessionRequest_CanSerializeEnableSessionTelemetry_WithSdkOptions()
     {

go/client_test.go

@@ -402,6 +402,33 @@ func TestResumeSessionRequest_ClientName(t *testing.T) {
 	})
 }
 
+func TestSessionMetadata_ClientName(t *testing.T) {
+	t.Run("round-trips clientName in JSON", func(t *testing.T) {
+		var metadata SessionMetadata
+		if err := json.Unmarshal([]byte(`{
+			"sessionId":"s1",
+			"startTime":"2025-01-01T00:00:00Z",
+			"modifiedTime":"2025-01-01T01:00:00Z",
+			"summary":"loaded session",
+			"clientName":"my-app",
+			"isRemote":false
+		}`), &metadata); err != nil {
+			t.Fatalf("Failed to unmarshal: %v", err)
+		}
+		if metadata.ClientName == nil || *metadata.ClientName != "my-app" {
+			t.Fatalf("Expected clientName to be my-app, got %v", metadata.ClientName)
+		}
+
+		data, err := json.Marshal(metadata)
+		if err != nil {
+			t.Fatalf("Failed to marshal: %v", err)
+		}
+		if !strings.Contains(string(data), `"clientName":"my-app"`) {
+			t.Fatalf("Expected marshaled JSON to include clientName, got %s", string(data))
+		}
+	})
+}
+
 func TestCreateSessionRequest_Agent(t *testing.T) {
 	t.Run("includes agent in JSON when set", func(t *testing.T) {
 		req := createSessionRequest{Agent: "test-agent"}

go/types.go

@@ -1410,6 +1410,7 @@ type SessionMetadata struct {
 	StartTime    time.Time       `json:"startTime"`
 	ModifiedTime time.Time       `json:"modifiedTime"`
 	Summary      *string         `json:"summary,omitempty"`
+	ClientName   *string         `json:"clientName,omitempty"`
 	IsRemote     bool            `json:"isRemote"`
 	Context      *SessionContext `json:"context,omitempty"`
 }

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

@@ -46,6 +46,9 @@ public class SessionMetadata {
     @JsonProperty("summary")
     private String summary;
 
+    @JsonProperty("clientName")
+    private String clientName;
+
     @JsonProperty("isRemote")
     private boolean isRemote;
 
@@ -130,6 +133,25 @@ public void setSummary(String summary) {
         this.summary = summary;
     }
 
+    /**
+     * Gets the identifier of the client driving the session.
+     *
+     * @return the client name, or {@code null} if not available
+     */
+    public String getClientName() {
+        return clientName;
+    }
+
+    /**
+     * Sets the client identifier for the session.
+     *
+     * @param clientName
+     *            the client name
+     */
+    public void setClientName(String clientName) {
+        this.clientName = clientName;
+    }
+
     /**
      * Returns whether this session is stored remotely.
      *

java/src/test/java/com/github/copilot/ModelInfoTest.java

@@ -60,8 +60,11 @@ void sessionMetadataGettersAndSetters() {
         assertNull(meta.getStartTime());
         assertNull(meta.getModifiedTime());
         assertNull(meta.getSummary());
+        assertNull(meta.getClientName());
         assertFalse(meta.isRemote());
 
+        meta.setClientName("my-app");
+        assertEquals("my-app", meta.getClientName());
         meta.setRemote(true);
         assertTrue(meta.isRemote());
     }

nodejs/src/client.ts

@@ -1316,6 +1316,7 @@ export class CopilotClient {
                 startTime: string;
                 modifiedTime: string;
                 summary?: string;
+                clientName?: string;
                 isRemote: boolean;
                 context?: { cwd: string; gitRoot?: string; repository?: string; branch?: string };
             }>;
@@ -1354,6 +1355,7 @@ export class CopilotClient {
                 startTime: string;
                 modifiedTime: string;
                 summary?: string;
+                clientName?: string;
                 isRemote: boolean;
                 context?: { cwd: string; gitRoot?: string; repository?: string; branch?: string };
             };
@@ -1371,6 +1373,7 @@ export class CopilotClient {
         startTime: string;
         modifiedTime: string;
         summary?: string;
+        clientName?: string;
         isRemote: boolean;
         context?: { cwd: string; gitRoot?: string; repository?: string; branch?: string };
     }): SessionMetadata {
@@ -1380,6 +1383,7 @@ export class CopilotClient {
             startTime: new Date(raw.startTime),
             modifiedTime: new Date(raw.modifiedTime),
             summary: raw.summary,
+            clientName: raw.clientName,
             isRemote: raw.isRemote,
             context: context
                 ? {

nodejs/src/types.ts

@@ -2027,6 +2027,8 @@ export interface SessionMetadata {
     startTime: Date;
     modifiedTime: Date;
     summary?: string;
+    /** Identifier of the client driving the session */
+    clientName?: string;
     isRemote: boolean;
     /** Working directory context (working directory, git info) from session creation */
     context?: SessionContext;

nodejs/test/client.test.ts

@@ -240,6 +240,80 @@ describe("CopilotClient", () => {
         spy.mockRestore();
     });
 
+    it("maps clientName from session.list responses", async () => {
+        const client = new CopilotClient();
+        await client.start();
+        onTestFinished(() => client.forceStop());
+
+        vi.spyOn((client as any).connection!, "sendRequest").mockImplementation(
+            async (method: string) => {
+                if (method === "session.list") {
+                    return {
+                        sessions: [
+                            {
+                                sessionId: "session-1",
+                                startTime: "2025-01-01T00:00:00Z",
+                                modifiedTime: "2025-01-01T01:00:00Z",
+                                summary: "test session",
+                                clientName: "my-app",
+                                isRemote: false,
+                            },
+                        ],
+                    };
+                }
+                throw new Error(`Unexpected method: ${method}`);
+            }
+        );
+
+        const sessions = await client.listSessions();
+
+        expect(sessions).toEqual([
+            expect.objectContaining({
+                sessionId: "session-1",
+                clientName: "my-app",
+                summary: "test session",
+            }),
+        ]);
+        expect(sessions[0].startTime).toBeInstanceOf(Date);
+        expect(sessions[0].modifiedTime).toBeInstanceOf(Date);
+    });
+
+    it("maps clientName from session.getMetadata responses", async () => {
+        const client = new CopilotClient();
+        await client.start();
+        onTestFinished(() => client.forceStop());
+
+        vi.spyOn((client as any).connection!, "sendRequest").mockImplementation(
+            async (method: string) => {
+                if (method === "session.getMetadata") {
+                    return {
+                        session: {
+                            sessionId: "session-1",
+                            startTime: "2025-01-01T00:00:00Z",
+                            modifiedTime: "2025-01-01T01:00:00Z",
+                            summary: "loaded session",
+                            clientName: "my-app",
+                            isRemote: false,
+                        },
+                    };
+                }
+                throw new Error(`Unexpected method: ${method}`);
+            }
+        );
+
+        const metadata = await client.getSessionMetadata("session-1");
+
+        expect(metadata).toEqual(
+            expect.objectContaining({
+                sessionId: "session-1",
+                clientName: "my-app",
+                summary: "loaded session",
+            })
+        );
+        expect(metadata?.startTime).toBeInstanceOf(Date);
+        expect(metadata?.modifiedTime).toBeInstanceOf(Date);
+    });
+
     it("forwards enableSessionTelemetry in session.create request", async () => {
         const client = new CopilotClient();
         await client.start();

python/copilot/client.py

@@ -780,6 +780,7 @@ class SessionMetadata:
     modified_time: datetime  # Timestamp when session was last modified
     is_remote: bool  # Whether the session is remote
     summary: str | None = None  # Optional summary of the session
+    client_name: str | None = None  # Identifier of the client driving the session
     context: SessionContext | None = None  # Working directory context
 
     @staticmethod
@@ -795,6 +796,7 @@ def from_dict(obj: Any) -> SessionMetadata:
                 f"startTime={start_time}, modifiedTime={modified_time}, isRemote={is_remote}"
             )
         summary = obj.get("summary")
+        client_name = obj.get("clientName")
         context_dict = obj.get("context")
         context = SessionContext.from_dict(context_dict) if context_dict else None
         return SessionMetadata(
@@ -803,6 +805,7 @@ def from_dict(obj: Any) -> SessionMetadata:
             modified_time=_parse_session_timestamp(modified_time),
             is_remote=bool(is_remote),
             summary=summary,
+            client_name=client_name,
             context=context,
         )
 
@@ -814,6 +817,8 @@ def to_dict(self) -> dict:
         result["isRemote"] = self.is_remote
         if self.summary is not None:
             result["summary"] = self.summary
+        if self.client_name is not None:
+            result["clientName"] = self.client_name
         if self.context is not None:
             result["context"] = self.context.to_dict()
         return result