---
title: "Reference: Agents API | Client SDK"
description: Learn how to interact with Mastra AI agents, including generating responses, streaming interactions, and managing agent tools using the client-js SDK.
packages:
  - "@mastra/ai-sdk"
  - "@mastra/client-js"
  - "@mastra/core"
---

# Agents API

The Agents API provides methods to interact with Mastra AI agents, including generating responses, streaming interactions, and managing agent tools.

## Getting All Agents

Retrieve a list of all available agents:

```typescript
const agents = await mastraClient.listAgents();
```

Returns a record of agent IDs to their serialized agent configurations.

## Working with a Specific Agent

Get an instance of a specific agent by its ID:

```typescript title="src/mastra/agents/my-agent.ts"
export const myAgent = new Agent({
  id: "my-agent",
});
```

```typescript
const agent = mastraClient.getAgent("my-agent");
```

## Agent Methods

### details()

Retrieve detailed information about an agent:

```typescript
const details = await agent.details();
```

### generate()

Generate a response from the agent:

```typescript
const response = await agent.generate(
  [
    {
      role: "user",
      content: "Hello, how are you?",
    },
  ],
  {
    memory: {
      thread: "thread-abc", // Optional: Thread ID for conversation context
      resource: "user-123", // Optional: Resource ID
    },
    structuredOutput: {}    // Optional: Structured Output configuration
  }
);
```

You can also use the simplified string format:

```typescript
const response = await agent.generate("Hello, how are you?", {
  threadId: "thread-1",
  resourceId: "resource-1",
});
```

### stream()

Stream responses from the agent for real-time interactions:

```typescript
const response = await agent.stream("Tell me a story");

// Process data stream with the processDataStream util
response.processDataStream({
  onChunk: async (chunk) => {
    console.log(chunk);
  },
});
```

You can also use the simplified string format:

```typescript
const response = await agent.stream("Tell me a story", {
  threadId: "thread-1",
  clientTools: { colorChangeTool },
});

response.processDataStream({
  onChunk: async (chunk) => {
    if (chunk.type === "text-delta") {
      console.log(chunk.payload.text);
    }
  },
});
```

You can also read from response body directly:

```typescript
const reader = response.body.getReader();
while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  console.log(new TextDecoder().decode(value));
}
```

#### AI SDK compatible format

To stream AI SDK-formatted parts on the client from an `agent.stream(...)` response, wrap `response.processDataStream` into a `ReadableStream<ChunkType>` and use `toAISdkStream`:

```typescript title="client-ai-sdk-transform.ts"
import { createUIMessageStream } from "ai";
import { toAISdkStream } from "@mastra/ai-sdk";
import type { ChunkType, MastraModelOutput } from "@mastra/core/stream";

const response = await agent.stream({ messages: "Tell me a story" });

const chunkStream: ReadableStream<ChunkType> = new ReadableStream<ChunkType>({
  start(controller) {
    response
      .processDataStream({
        onChunk: async (chunk) => controller.enqueue(chunk as ChunkType),
      })
      .finally(() => controller.close());
  },
});

const uiMessageStream = createUIMessageStream({
  execute: async ({ writer }) => {
    for await (const part of toAISdkStream(
      chunkStream as unknown as MastraModelOutput,
      { from: "agent" },
    )) {
      writer.write(part);
    }
  },
});

for await (const part of uiMessageStream) {
  console.log(part);
}
```

### getTool()

Retrieve information about a specific tool available to the agent:

```typescript
const tool = await agent.getTool("tool-id");
```

### executeTool()

Execute a specific tool for the agent:

```typescript
const result = await agent.executeTool("tool-id", {
  data: { input: "value" },
});
```

### network()

Stream responses from an agent network for multi-agent interactions:

```typescript
const response = await agent.network({
  messages: [
    {
      role: "user",
      content: "Research this topic and write a summary",
    },
  ],
});

response.processDataStream({
  onChunk: async (chunk) => {
    console.log(chunk);
  },
});
```

### approveToolCall()

Approve a pending tool call that requires human confirmation:

```typescript
const response = await agent.approveToolCall({
  runId: "run-123",
  toolCallId: "tool-call-456",
});

response.processDataStream({
  onChunk: async (chunk) => {
    console.log(chunk);
  },
});
```

### declineToolCall()

Decline a pending tool call that requires human confirmation:

```typescript
const response = await agent.declineToolCall({
  runId: "run-123",
  toolCallId: "tool-call-456",
});

response.processDataStream({
  onChunk: async (chunk) => {
    console.log(chunk);
  },
});
```

## Client Tools

Client-side tools allow you to execute custom functions on the client side when the agent requests them.

```typescript
import { createTool } from "@mastra/client-js";
import { z } from "zod";

const colorChangeTool = createTool({
  id: "changeColor",
  description: "Changes the background color",
  inputSchema: z.object({
    color: z.string(),
  }),
  execute: async (inputData) => {
    document.body.style.backgroundColor = inputData.color;
    return { success: true };
  },
});

// Use with generate
const response = await agent.generate("Change the background to blue", {
  clientTools: { colorChangeTool },
});

// Use with stream
const response = await agent.stream("Tell me a story", {
  memory: {
    thread: "thread-1",
    resource: "resource-1",
  },
  clientTools: { colorChangeTool },
});

response.processDataStream({
  onChunk: async (chunk) => {
    if (chunk.type === "text-delta") {
      console.log(chunk.payload.text);
    } else if (chunk.type === "tool-call") {
      console.log(
        `calling tool ${chunk.payload.toolName} with args ${JSON.stringify(
          chunk.payload.args,
          null,
          2
        )}`
      );
    }
  },
});
```

## Stored Agents

Stored agents are agent configurations stored in a database that can be created, updated, and deleted at runtime. They reference primitives (tools, workflows, other agents, memory, scorers) by key, which are resolved from the Mastra registry when the agent is instantiated.

### listStoredAgents()

Retrieve a paginated list of all stored agents:

```typescript
const result = await mastraClient.listStoredAgents();
console.log(result.agents); // Array of stored agents
console.log(result.total); // Total count
```

With pagination and ordering:

```typescript
const result = await mastraClient.listStoredAgents({
  page: 0,
  perPage: 20,
  orderBy: {
    field: "createdAt",
    direction: "DESC",
  },
});
```

### createStoredAgent()

Create a new stored agent:

```typescript
const agent = await mastraClient.createStoredAgent({
  id: "my-agent",
  name: "My Assistant",
  instructions: "You are a helpful assistant.",
  model: {
    provider: "openai",
    name: "gpt-4",
  },
});
```

With all options:

```typescript
const agent = await mastraClient.createStoredAgent({
  id: "full-agent",
  name: "Full Agent",
  description: "A fully configured agent",
  instructions: "You are a helpful assistant.",
  model: {
    provider: "openai",
    name: "gpt-4",
  },
  tools: ["calculator", "weather"],
  workflows: ["data-processing"],
  agents: ["sub-agent-1"],
  memory: "my-memory",
  scorers: {
    "quality-scorer": {
      sampling: { type: "ratio", rate: 0.1 },
    },
  },
  defaultOptions: {
    maxSteps: 10,
  },
  metadata: {
    version: "1.0",
    team: "engineering",
  },
});
```

### getStoredAgent()

Get an instance of a specific stored agent:

```typescript
const storedAgent = mastraClient.getStoredAgent("my-agent");
```

## Stored Agent Methods

### details()

Retrieve the stored agent configuration:

```typescript
const details = await storedAgent.details();
console.log(details.name);
console.log(details.instructions);
console.log(details.model);
```

### update()

Update specific fields of a stored agent. All fields are optional:

```typescript
const updated = await storedAgent.update({
  name: "Updated Agent Name",
  instructions: "New instructions for the agent.",
});
```

```typescript
// Update just the tools
await storedAgent.update({
  tools: ["new-tool-1", "new-tool-2"],
});

// Update metadata
await storedAgent.update({
  metadata: {
    version: "2.0",
    lastModifiedBy: "admin",
  },
});
```

### delete()

Delete a stored agent:

```typescript
const result = await storedAgent.delete();
console.log(result.success); // true
```
