diff --git a/src/ai/ai.ts b/src/ai/ai.ts
index 3acf907c..3b7593d1 100644
--- a/src/ai/ai.ts
+++ b/src/ai/ai.ts
@@ -28,7 +28,7 @@ export class Ai extends FactoryBase {
    * Sets up ai configuration for an AINFT object.
    * @param {string} objectId - The ID of the AINFT object.
    * @param {string} serviceName - The name of Ainize service.
-   * @returns {Promise<AiConfigurationTransactionResult>} Returns a promise that resolves with both the transaction result and the configuration info.
+   * @returns {Promise<AiConfigurationTransactionResult>} A promise that resolves with both the transaction result and the configuration info.
    */
   async configure(
     objectId: string,
@@ -49,7 +49,7 @@ export class Ai extends FactoryBase {
   /**
    * Retrieves the credit balance for a service.
    * @param {string} serviceName - The name of Ainize service.
-   * @returns {Promise<number|null>} Returns a promise that resolves with the credit balance.
+   * @returns {Promise<number|null>} A promise that resolves with the credit balance.
    */
   async getCredit(serviceName: string): Promise<number> {
     const address = await this.ain.signer.getAddress();
@@ -80,7 +80,7 @@ export class Ai extends FactoryBase {
    * Deposits a credits for a service.
    * @param {string} serviceName - The name of Ainize service.
    * @param {number} amount - The amount of credits to deposit.
-   * @returns {Promise<CreditTransactionResult>} Returns a promise that resolves with the deposit transaction info.
+   * @returns {Promise<CreditTransactionResult>} A promise that resolves with the deposit transaction info.
    */
   /*
   async depositCredit(serviceName: string, amount: number): Promise<CreditTransactionResult> {
diff --git a/src/ai/assistant.ts b/src/ai/assistant.ts
index 69cff0ed..c5c4e696 100644
--- a/src/ai/assistant.ts
+++ b/src/ai/assistant.ts
@@ -58,7 +58,7 @@ export class Assistants extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {AssistantCreateParams} AssistantCreateParams - The parameters to create assistant.
    * @param {AssistantCreateOptions} AssistantCreateOptions - The creation options.
-   * @returns Returns a promise that resolves with both the transaction result and the created assistant.
+   * @returns A promise that resolves with both the transaction result and the created assistant.
    */
   async create(
     objectId: string,
@@ -117,7 +117,7 @@ export class Assistants extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} assistantId - The ID of assistant.
    * @param {AssistantUpdateParams} AssistantUpdateParams - The parameters to update assistant.
-   * @returns Returns a promise that resolves with both the transaction result and the updated assistant.
+   * @returns A promise that resolves with both the transaction result and the updated assistant.
    */
   async update(
     objectId: string,
@@ -175,7 +175,7 @@ export class Assistants extends FactoryBase {
    * @param {string} objectId - The ID of AINFT object.
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} assistantId - The ID of assistant.
-   * @returns Returns a promise that resolves with both the transaction result and the deleted assistant.
+   * @returns A promise that resolves with both the transaction result and the deleted assistant.
    */
   async delete(
     objectId: string,
@@ -220,7 +220,7 @@ export class Assistants extends FactoryBase {
    * @param {string} objectId - The ID of AINFT object.
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} assistantId - The ID of assistant.
-   * @returns Returns a promise that resolves with the assistant.
+   * @returns A promise that resolves with the assistant.
    */
   async get(objectId: string, tokenId: string, assistantId: string): Promise<Assistant> {
     const appId = AinftObject.getAppId(objectId);
@@ -249,18 +249,18 @@ export class Assistants extends FactoryBase {
   /**
    * Retrieves a list of assistants.
    * @param {string} objectId - The ID of AINFT object.
-   * @param {string} address - The checksum address of account.
-   * @param {QueryParams} QueryParams - The parameters for querying items.
-   * @returns Returns a promise that resolves with the list of assistants.
+   * @param {string} [address] - (Optional) The checksum address of account.
+   * @param {QueryParams} [queryParams={}] - The parameters for querying items.
+   * @returns A promise that resolves with the list of assistants.
    */
   async list(
     objectId: string,
-    address: string,
+    address?: string | null,
     { limit = 20, offset = 0, order = 'desc' }: QueryParams = {}
   ) {
     await validateObject(this.ain, objectId);
 
-    const tokens = await this.getTokensByAddress(objectId, address);
+    const tokens = await this.getTokens(objectId, address);
     const assistants = this.getAssistantsFromTokens(tokens);
     const sorted = this.sortAssistants(assistants, order);
 
@@ -393,12 +393,12 @@ export class Assistants extends FactoryBase {
     );
   }
 
-  private async getTokensByAddress(objectId: string, address: string) {
+  private async getTokens(objectId: string, address?: string | null) {
     const appId = AinftObject.getAppId(objectId);
     const tokensPath = Path.app(appId).tokens().value();
     const tokens: NftTokens = (await this.ain.db.ref(tokensPath).getValue()) || {};
     return Object.entries(tokens).reduce<NftToken[]>((acc, [id, token]) => {
-      if (token.owner === address) {
+      if (!address || token.owner === address) {
         acc.push({ tokenId: id, ...token });
       }
       return acc;
@@ -408,13 +408,13 @@ export class Assistants extends FactoryBase {
   private getAssistantsFromTokens(tokens: NftToken[]) {
     return tokens.reduce<Assistant[]>((acc, token) => {
       if (token.ai) {
-        acc.push(this.toAssistant(token));
+        acc.push(this.toAssistant(token, this.countThreads(token.ai.history)));
       }
       return acc;
     }, []);
   }
 
-  private toAssistant(data: any): Assistant {
+  private toAssistant(data: any, numThreads: number): Assistant {
     return {
       id: data.ai.id,
       tokenId: data.tokenId,
@@ -425,6 +425,7 @@ export class Assistants extends FactoryBase {
       description: data.ai.config.description || null,
       metadata: data.ai.config.metadata || {},
       created_at: data.ai.createdAt,
+      metric: { numThreads },
     };
   }
 
@@ -435,4 +436,17 @@ export class Assistants extends FactoryBase {
       return 0;
     });
   }
+
+  private countThreads(items: any) {
+    if (typeof items !== 'object' || !items) {
+      return 0;
+    }
+    return Object.values(items).reduce((sum: number, item: any) => {
+      const count =
+        item.threads && typeof item.threads === 'object'
+          ? Object.keys(item.threads).length
+          : 0;
+      return sum + count;
+    }, 0);
+  }
 }
diff --git a/src/ai/message.ts b/src/ai/message.ts
index 10dc1990..93785df8 100644
--- a/src/ai/message.ts
+++ b/src/ai/message.ts
@@ -34,7 +34,7 @@ export class Messages extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} threadId - The ID of thread.
    * @param {MessageCreateParams} MessageCreateParams - The parameters to create message.
-   * @returns Returns a promise that resolves with both the transaction result and a list including the new message.
+   * @returns A promise that resolves with both the transaction result and a list including the new message.
    */
   async create(
     objectId: string,
@@ -76,7 +76,7 @@ export class Messages extends FactoryBase {
    * @param {string} threadId - The ID of thread.
    * @param {string} messageId - The ID of message.
    * @param {MessageUpdateParams} MessageUpdateParams - The parameters to update message.
-   * @returns Returns a promise that resolves with both the transaction result and the updated message.
+   * @returns A promise that resolves with both the transaction result and the updated message.
    */
   async update(
     objectId: string,
@@ -122,7 +122,7 @@ export class Messages extends FactoryBase {
    * @param {string} threadId - The ID of thread.
    * @param {string} messageId - The ID of message.
    * @param {string} address - The checksum address of account.
-   * @returns Returns a promise that resolves with the message.
+   * @returns A promise that resolves with the message.
    */
   async get(
     objectId: string,
@@ -156,7 +156,7 @@ export class Messages extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} threadId - The ID of thread.
    * @param {string} address - The checksum address of account.
-   * @returns Returns a promise that resolves with the list of messages.
+   * @returns A promise that resolves with the list of messages.
    */
   async list(
     objectId: string,
diff --git a/src/ai/thread.ts b/src/ai/thread.ts
index 70a1140a..4fc39879 100644
--- a/src/ai/thread.ts
+++ b/src/ai/thread.ts
@@ -35,7 +35,7 @@ export class Threads extends FactoryBase {
    * @param {string} objectId - The ID of AINFT object.
    * @param {string} tokenId - The ID of AINFT token.
    * @param {ThreadCreateParams} ThreadCreateParams - The parameters to create thread.
-   * @returns Returns a promise that resolves with both the transaction result and the created thread.
+   * @returns A promise that resolves with both the transaction result and the created thread.
    */
   async create(
     objectId: string,
@@ -88,7 +88,7 @@ export class Threads extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} threadId - The ID of thread.
    * @param {ThreadUpdateParams} ThreadUpdateParams - The parameters to update thread.
-   * @returns Returns a promise that resolves with both the transaction result and the updated thread.
+   * @returns A promise that resolves with both the transaction result and the updated thread.
    */
   async update(
     objectId: string,
@@ -129,7 +129,7 @@ export class Threads extends FactoryBase {
    * @param {string} objectId - The ID of AINFT object.
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} threadId - The ID of thread.
-   * @returns Returns a promise that resolves with both the transaction result and the deleted thread.
+   * @returns A promise that resolves with both the transaction result and the deleted thread.
    */
   async delete(
     objectId: string,
@@ -167,7 +167,7 @@ export class Threads extends FactoryBase {
    * @param {string} tokenId - The ID of AINFT token.
    * @param {string} threadId - The ID of thread.
    * @param {string} address - The checksum address of account.
-   * @returns Returns a promise that resolves with the thread.
+   * @returns A promise that resolves with the thread.
    */
   async get(objectId: string, tokenId: string, threadId: string, address: string): Promise<Thread> {
     await validateObject(this.ain, objectId);
@@ -198,7 +198,7 @@ export class Threads extends FactoryBase {
    * @param {string | null} [tokenId] - The ID of AINFT token.
    * @param {string | null} [address] - The checksum address of account.
    * @param {QueryParams} QueryParams - The parameters for querying items.
-   * @returns Returns a promise that resolves with the list of threads.
+   * @returns A promise that resolves with the list of threads.
    */
   async list(
     objectId: string,
diff --git a/src/ainft721Object.ts b/src/ainft721Object.ts
index 5a225a7c..a5fd1a79 100644
--- a/src/ainft721Object.ts
+++ b/src/ainft721Object.ts
@@ -17,8 +17,6 @@ export default class Ainft721Object extends FactoryBase {
   readonly owner: string;
   /** The ID of app in AIN blockchain. */
   readonly appId: string;
-  /** The description of AINFT object. */
-  readonly description?: string | null;
   /** The metadata of AINFT object. */
   readonly metadata?: Metadata;
 
@@ -29,7 +27,8 @@ export default class Ainft721Object extends FactoryBase {
    * @param objectInfo.id The ID of AINFT object.
    * @param objectInfo.name The name of AINFT object.
    * @param objectInfo.symbol The symbol of AINFT object.
-   * @param objectInfo.owner Owner of AINFT object.
+   * @param objectInfo.owner The owner of AINFT object.
+   * @param objectInfo.metadata The metadata of AINFT object.
    * @param ain Ain instance to sign and send transaction to AIN blockchain.
    * @param baseUrl The base url to request api to AINFT factory server.
    */
@@ -39,7 +38,6 @@ export default class Ainft721Object extends FactoryBase {
       name: string;
       symbol: string;
       owner: string;
-      description?: string;
       metadata?: Metadata;
     },
     ain: Ain,
@@ -51,7 +49,6 @@ export default class Ainft721Object extends FactoryBase {
     this.symbol = objectInfo.symbol;
     this.owner = objectInfo.owner;
     this.appId = Ainft721Object.getAppId(objectInfo.id);
-    this.description = objectInfo.description || null;
     this.metadata = objectInfo.metadata || {};
   }
 
diff --git a/src/nft.ts b/src/nft.ts
index c0bbd73d..7eb955f1 100644
--- a/src/nft.ts
+++ b/src/nft.ts
@@ -41,14 +41,13 @@ export default class Nft extends FactoryBase {
    *  });
    * ```
    */
-  async create({ name, symbol, description, metadata }: AinftObjectCreateParams): Promise<{ txHash: string; ainftObject: Ainft721Object }> {
+  async create({ name, symbol, metadata }: AinftObjectCreateParams): Promise<{ txHash: string; ainftObject: Ainft721Object }> {
     const address = await this.ain.signer.getAddress();
 
     const body = {
       address,
       name,
       symbol,
-      ...(description && { description }),
       ...(metadata && !_.isEmpty(metadata) && { metadata }),
     };
     const trailingUrl = 'native';
diff --git a/src/types.ts b/src/types.ts
index 379251ca..fa53e634 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1125,10 +1125,8 @@ export interface AinftObjectCreateParams {
   name: string;
   /** The symbol of the AINFT object. */
   symbol: string;
-  /** The description of the AINFT object. */
-  description?: string | null;
   /** The metadata of the AINFT object. */
-  metadata?: Metadata | null;
+  metadata?: Metadata;
 }
 
 export enum ServiceType {
@@ -1242,6 +1240,8 @@ export interface Assistant {
    * with keys limited to 64 characters and values to 512 characters.
    */
   metadata: object | null;
+  /** The metric of the assistant. */
+  metric?: { [key: string]: number } | null;
   /** The UNIX timestamp in seconds. */
   created_at: number;
 }
diff --git a/test/ai/assistant.test.ts b/test/ai/assistant.test.ts
index 46dec5e5..c2ffb90e 100644
--- a/test/ai/assistant.test.ts
+++ b/test/ai/assistant.test.ts
@@ -50,7 +50,7 @@ describe.skip('assistant', () => {
   });
 
   it('should list assistants', async () => {
-    const result = await ainft.assistant.list(objectId, address);
+    const result = await ainft.assistant.list(objectId, null);
 
     expect(result.total).toBeDefined();
     expect(result.items).toBeDefined();
diff --git a/test/nft.test.ts b/test/nft.test.ts
index fc1b245d..633b8603 100644
--- a/test/nft.test.ts
+++ b/test/nft.test.ts
@@ -2,7 +2,7 @@ import AinftJs from '../src/ainft';
 import { AINFT_OBJECT_REGEX, TX_HASH_REGEX } from './constants';
 import { address, privateKey } from './test_data';
 
-describe('nft', () => {
+describe.skip('nft', () => {
   const ainft = new AinftJs({
     privateKey,
     baseUrl: 'https://ainft-api-dev.ainetwork.ai',
@@ -14,12 +14,12 @@ describe('nft', () => {
     const result = await ainft.nft.create({
       name: 'name',
       symbol: 'symbol',
-      description: 'description',
       metadata: {
         author: {
           address: address,
           username: 'username',
         },
+        description: 'description',
         logoImage: 'https://picsum.photos/200/200',
         bannerImage: 'https://picsum.photos/1400/264',
         externalLink: 'https://example.com',
@@ -31,12 +31,12 @@ describe('nft', () => {
     expect(result.ainftObject.name).toBe('name');
     expect(result.ainftObject.symbol).toBe('symbol');
     expect(result.ainftObject.owner).toBe(address);
-    expect(result.ainftObject.description).toBe('description');
     expect(result.ainftObject.metadata).toEqual({
       author: {
         address: address,
         username: 'username',
       },
+      description: 'description',
       logoImage: 'https://picsum.photos/200/200',
       bannerImage: 'https://picsum.photos/1400/264',
       externalLink: 'https://example.com',