diff --git a/packages/backend/server/src/plugins/copilot/context/resolver.ts b/packages/backend/server/src/plugins/copilot/context/resolver.ts
index 7ba20a236..d585486e6 100644
--- a/packages/backend/server/src/plugins/copilot/context/resolver.ts
+++ b/packages/backend/server/src/plugins/copilot/context/resolver.ts
@@ -146,7 +146,11 @@ export class CopilotContextRootResolver {
     if (!lock) {
       return new TooManyRequest('Server is busy');
     }
-    await this.checkChatSession(user, sessionId, copilot.workspaceId);
+    await this.checkChatSession(
+      user,
+      sessionId,
+      copilot.workspaceId || undefined
+    );
 
     if (contextId) {
       const context = await this.context.get(contextId);
diff --git a/packages/backend/server/src/plugins/copilot/resolver.ts b/packages/backend/server/src/plugins/copilot/resolver.ts
index fc9c916a7..7c9703b76 100644
--- a/packages/backend/server/src/plugins/copilot/resolver.ts
+++ b/packages/backend/server/src/plugins/copilot/resolver.ts
@@ -196,7 +196,7 @@ class CopilotHistoriesType implements Partial<ChatHistory> {
     description: 'An mark identifying which view to use to display the session',
     nullable: true,
   })
-  action!: string | undefined;
+  action!: string | null;
 
   @Field(() => Number, {
     description: 'The number of tokens used in the session',
@@ -281,7 +281,7 @@ class CopilotSessionType {
   id!: string;
 
   @Field(() => ID, { nullable: true })
-  parentSessionId!: string | undefined;
+  parentSessionId!: string | null;
 
   @Field(() => String)
   promptName!: string;
@@ -292,10 +292,7 @@ class CopilotSessionType {
 @ObjectType('Copilot')
 export class CopilotType {
   @Field(() => ID, { nullable: true })
-  workspaceId!: string | undefined;
-
-  @Field(() => ID, { nullable: true })
-  docId!: string | undefined;
+  workspaceId!: string | null;
 }
 
 @Throttle()
@@ -575,7 +572,7 @@ export class UserCopilotResolver {
         .allowLocal()
         .assert('Workspace.Copilot');
     }
-    return { workspaceId };
+    return { workspaceId: workspaceId || null };
   }
 }
 
diff --git a/packages/backend/server/src/plugins/copilot/session.ts b/packages/backend/server/src/plugins/copilot/session.ts
index 94ec7bea3..cdbedf0cd 100644
--- a/packages/backend/server/src/plugins/copilot/session.ts
+++ b/packages/backend/server/src/plugins/copilot/session.ts
@@ -409,7 +409,7 @@ export class ChatSessionService {
   ): Promise<
     Array<{
       id: string;
-      parentSessionId?: string;
+      parentSessionId: string | null;
       promptName: string;
     }>
   > {
@@ -433,7 +433,7 @@ export class ChatSessionService {
       .then(sessions =>
         sessions.map(({ id, parentSessionId, promptName }) => ({
           id,
-          parentSessionId: parentSessionId || undefined,
+          parentSessionId: parentSessionId || null,
           promptName,
         }))
       );
@@ -548,7 +548,7 @@ export class ChatSessionService {
 
                   return {
                     sessionId: id,
-                    action: prompt.action || undefined,
+                    action: prompt.action || null,
                     tokens: tokenCost,
                     createdAt,
                     messages: preload.concat(ret.data),
diff --git a/packages/backend/server/src/plugins/copilot/types.ts b/packages/backend/server/src/plugins/copilot/types.ts
index 9070b406e..a8ee21e12 100644
--- a/packages/backend/server/src/plugins/copilot/types.ts
+++ b/packages/backend/server/src/plugins/copilot/types.ts
@@ -101,7 +101,7 @@ export type SubmittedMessage = z.infer<typeof SubmittedMessageSchema>;
 export const ChatHistorySchema = z
   .object({
     sessionId: z.string(),
-    action: z.string().optional(),
+    action: z.string().nullable(),
     tokens: z.number(),
     messages: z.array(PromptMessageSchema.or(ChatMessageSchema)),
     createdAt: z.date(),
diff --git a/packages/backend/server/src/schema.gql b/packages/backend/server/src/schema.gql
index 57b0c723e..7893a4739 100644
--- a/packages/backend/server/src/schema.gql
+++ b/packages/backend/server/src/schema.gql
@@ -39,7 +39,6 @@ enum ContextFileStatus {
 type Copilot {
   """Get the context list of a session"""
   contexts(contextId: String, sessionId: String!): [CopilotContext!]!
-  docId: ID
   histories(docId: String, options: QueryChatHistoriesInput): [CopilotHistories!]!
 
   """Get the quota of the user in the workspace"""
diff --git a/packages/frontend/graphql/src/schema.ts b/packages/frontend/graphql/src/schema.ts
index 4c9e1774e..3d6870d97 100644
--- a/packages/frontend/graphql/src/schema.ts
+++ b/packages/frontend/graphql/src/schema.ts
@@ -78,7 +78,6 @@ export interface Copilot {
   __typename?: 'Copilot';
   /** Get the context list of a session */
   contexts: Array<CopilotContext>;
-  docId: Maybe<Scalars['ID']['output']>;
   histories: Array<CopilotHistories>;
   /** Get the quota of the user in the workspace */
   quota: CopilotQuota;