qwen-code/docs/developers/sdk-typescript.md

Typescript SDK

@qwen-code/sdk

A minimum experimental TypeScript SDK for programmatic access to Qwen Code.

Feel free to submit a feature request/issue/PR.

Installation

npm install @qwen-code/sdk

Requirements

• Node.js >= 22.0.0
• Qwen Code >= 0.4.0 (stable) installed and accessible in PATH

Note for nvm users: If you use nvm to manage Node.js versions, the SDK may not be able to auto-detect the Qwen Code executable. You should explicitly set the pathToQwenExecutable option to the full path of the qwen binary.

Quick Start

import { query } from '@qwen-code/sdk';

// Single-turn query
const result = query({
  prompt: 'What files are in the current directory?',
  options: {
    cwd: '/path/to/project',
  },
});

// Iterate over messages
for await (const message of result) {
  if (message.type === 'assistant') {
    console.log('Assistant:', message.message.content);
  } else if (message.type === 'result') {
    console.log('Result:', message.result);
  }
}

API Reference

query(config)

Creates a new query session with the Qwen Code.

Parameters

• prompt: string | AsyncIterable<SDKUserMessage> - The prompt to send. Use a string for single-turn queries or an async iterable for multi-turn conversations.
• options: QueryOptions - Configuration options for the query session.

QueryOptions

Option	Type	Default	Description
cwd	string	process.cwd()	The working directory for the query session. Determines the context in which file operations and commands are executed.
model	string	-	The AI model to use (e.g., 'qwen-max', 'qwen-plus', 'qwen-turbo'). Takes precedence over OPENAI_MODEL and QWEN_MODEL environment variables.
pathToQwenExecutable	string	Auto-detected	Path to the Qwen Code executable. Supports multiple formats: 'qwen' (native binary from PATH), '/path/to/qwen' (explicit path), '/path/to/cli.js' (Node.js bundle), 'node:/path/to/cli.js' (force Node.js runtime), 'bun:/path/to/cli.js' (force Bun runtime). If not provided, auto-detects from: QWEN_CODE_CLI_PATH env var, ~/.volta/bin/qwen, ~/.npm-global/bin/qwen, /usr/local/bin/qwen, ~/.local/bin/qwen, ~/node_modules/.bin/qwen, ~/.yarn/bin/qwen.
permissionMode	'default' | 'plan' | 'auto-edit' | 'yolo'	'default'	Permission mode controlling tool execution approval. See Permission Modes for details.
canUseTool	CanUseTool	-	Custom permission handler for tool execution approval. Invoked when a tool requires confirmation. Must respond within 60 seconds or the request will be auto-denied. See Custom Permission Handler.
env	Record<string, string>	-	Environment variables to pass to the Qwen Code process. Merged with the current process environment.
systemPrompt	string | QuerySystemPromptPreset	-	System prompt configuration for the main session. Use a string to fully override the built-in Qwen Code system prompt, or a preset object to keep the built-in prompt and append extra instructions.
mcpServers	Record<string, McpServerConfig>	-	MCP (Model Context Protocol) servers to connect. Supports external servers (stdio/SSE/HTTP) and SDK-embedded servers. External servers are configured with transport options like command, args, url, httpUrl, etc. SDK servers use { type: 'sdk', name: string, instance: Server }.
abortController	AbortController	-	Controller to cancel the query session. Call abortController.abort() to terminate the session and cleanup resources.
debug	boolean	false	Enable debug mode for verbose logging from the CLI process.
maxSessionTurns	number	-1 (unlimited)	Maximum number of conversation turns before the session automatically terminates. A turn consists of a user message and an assistant response.
coreTools	string[]	-	Uses the legacy coreTools / CLI --core-tools allowlist semantics. If specified, only matching core tools are registered for the session. This is separate from permissions.allow, which auto-approves matching tool calls but does not restrict tool registration. Example: ['read_file', 'edit', 'run_shell_command'].
excludeTools	string[]	-	Equivalent to permissions.deny in settings.json. Excluded tools return a permission error immediately. Takes highest priority over all other permission settings. Supports tool name aliases and pattern matching: tool name ('write_file'), shell command prefix ('Bash(rm *)'), or path patterns ('Read(.env)', 'Edit(/src/**)').
allowedTools	string[]	-	Equivalent to permissions.allow in settings.json. Matching tools bypass canUseTool callback and execute automatically. Only applies when tool requires confirmation. Supports same pattern matching as excludeTools. Example: ['Bash(git status)', 'Bash(npm test)'].
authType	'openai' | 'qwen-oauth'	'openai'	Authentication type for the AI service. Qwen OAuth free tier was discontinued on 2026-04-15; new SDK setups should use OpenAI-compatible authentication or another supported provider.
agents	SubagentConfig[]	-	Configuration for subagents that can be invoked during the session. Subagents are specialized AI agents for specific tasks or domains.
includePartialMessages	boolean	false	When true, the SDK emits incomplete messages as they are being generated, allowing real-time streaming of the AI's response.
resume	string	-	Resume a previous session by providing its session ID. Equivalent to CLI's --resume flag.
sessionId	string	-	Specify a session ID for the new session. Ensures SDK and CLI use the same ID without resuming history. Equivalent to CLI's --session-id flag.

Note

For coreTools, aliases like Read, Edit, and Bash also work, but invocation specifiers such as Bash(git *) are stripped. coreTools restricts tool registration, not invocation patterns.

Timeouts

The SDK enforces the following default timeouts:

Timeout	Default	Description
canUseTool	1 minute	Maximum time for canUseTool callback to respond. If exceeded, the tool request is auto-denied.
mcpRequest	1 minute	Maximum time for SDK MCP tool calls to complete.
controlRequest	1 minute	Maximum time for control operations like initialize(), setModel(), setPermissionMode(), getContextUsage(), and interrupt() to complete.
streamClose	1 minute	Maximum time to wait for initialization to complete before closing CLI stdin in multi-turn mode with SDK MCP servers.

You can customize these timeouts via the timeout option:

const query = qwen.query('Your prompt', {
  timeout: {
    canUseTool: 60000, // 60 seconds for permission callback
    mcpRequest: 600000, // 10 minutes for MCP tool calls
    controlRequest: 60000, // 60 seconds for control requests
    streamClose: 15000, // 15 seconds for stream close wait
  },
});

Message Types

The SDK provides type guards to identify different message types:

import {
  isSDKUserMessage,
  isSDKAssistantMessage,
  isSDKSystemMessage,
  isSDKResultMessage,
  isSDKPartialAssistantMessage,
} from '@qwen-code/sdk';

for await (const message of result) {
  if (isSDKAssistantMessage(message)) {
    // Handle assistant message
  } else if (isSDKResultMessage(message)) {
    // Handle result message
  }
}

Query Instance Methods

The Query instance returned by query() provides several methods:

const q = query({ prompt: 'Hello', options: {} });

// Get session ID
const sessionId = q.getSessionId();

// Check if closed
const closed = q.isClosed();

// Interrupt the current operation
await q.interrupt();

// Change permission mode mid-session
await q.setPermissionMode('yolo');

// Change model mid-session
await q.setModel('qwen-max');

// Get context window usage breakdown (token counts per category)
const usage = await q.getContextUsage();
// Pass true to hint that per-item details should be displayed
const detail = await q.getContextUsage(true);

// Close the session
await q.close();

Permission Modes

The SDK supports different permission modes for controlling tool execution:

• default: Write tools are denied unless approved via canUseTool callback or in allowedTools. Read-only tools execute without confirmation.
• plan: Blocks all write tools, instructing AI to present a plan first.
• auto-edit: Auto-approve edit tools (edit, write_file, notebook_edit) while other tools require confirmation.
• yolo: All tools execute automatically without confirmation.

Permission Priority Chain

Decision priority (highest first): deny > ask > allow > (default/interactive mode)

The first matching rule wins.

1. excludeTools / permissions.deny - Blocks tools completely (returns permission error)
2. permissions.ask - Always requires user confirmation
3. permissionMode: 'plan' - Blocks all non-read-only tools
4. permissionMode: 'yolo' - Auto-approves all tools
5. allowedTools / permissions.allow - Auto-approves matching tools
6. canUseTool callback - Custom approval logic (if provided, not called for allowed tools)
7. Default behavior - Auto-deny in SDK mode (write tools require explicit approval)

Examples

Multi-turn Conversation

import { query, type SDKUserMessage } from '@qwen-code/sdk';

async function* generateMessages(): AsyncIterable<SDKUserMessage> {
  yield {
    type: 'user',
    session_id: 'my-session',
    message: { role: 'user', content: 'Create a hello.txt file' },
    parent_tool_use_id: null,
  };

  // Wait for some condition or user input
  yield {
    type: 'user',
    session_id: 'my-session',
    message: { role: 'user', content: 'Now read the file back' },
    parent_tool_use_id: null,
  };
}

const result = query({
  prompt: generateMessages(),
  options: {
    permissionMode: 'auto-edit',
  },
});

for await (const message of result) {
  console.log(message);
}

Custom Permission Handler

import { query, type CanUseTool } from '@qwen-code/sdk';

const canUseTool: CanUseTool = async (toolName, input, { signal }) => {
  // Allow all read operations
  if (toolName.startsWith('read_')) {
    return { behavior: 'allow', updatedInput: input };
  }

  // Prompt user for write operations (in a real app)
  const userApproved = await promptUser(`Allow ${toolName}?`);

  if (userApproved) {
    return { behavior: 'allow', updatedInput: input };
  }

  return { behavior: 'deny', message: 'User denied the operation' };
};

const result = query({
  prompt: 'Create a new file',
  options: {
    canUseTool,
  },
});

With External MCP Servers

import { query } from '@qwen-code/sdk';

const result = query({
  prompt: 'Use the custom tool from my MCP server',
  options: {
    mcpServers: {
      'my-server': {
        command: 'node',
        args: ['path/to/mcp-server.js'],
        env: { PORT: '3000' },
      },
    },
  },
});

Override the System Prompt

import { query } from '@qwen-code/sdk';

const result = query({
  prompt: 'Say hello in one sentence.',
  options: {
    systemPrompt: 'You are a terse assistant. Answer in exactly one sentence.',
  },
});

Append to the Built-in System Prompt

import { query } from '@qwen-code/sdk';

const result = query({
  prompt: 'Review the current directory.',
  options: {
    systemPrompt: {
      type: 'preset',
      preset: 'qwen_code',
      append: 'Be terse and focus on concrete findings.',
    },
  },
});

With SDK-Embedded MCP Servers

The SDK provides tool and createSdkMcpServer to create MCP servers that run in the same process as your SDK application. This is useful when you want to expose custom tools to the AI without running a separate server process.

tool(name, description, inputSchema, handler)

Creates a tool definition with Zod schema type inference.

Parameter	Type	Description
name	string	Tool name (1-64 chars, starts with letter, alphanumeric and underscores)
description	string	Human-readable description of what the tool does
inputSchema	ZodRawShape	Zod schema object defining the tool's input parameters
handler	(args, extra) => Promise<Result>	Async function that executes the tool and returns MCP content blocks

The handler must return a CallToolResult object with the following structure:

{
  content: Array<
    | { type: 'text'; text: string }
    | { type: 'image'; data: string; mimeType: string }
    | { type: 'resource'; uri: string; mimeType?: string; text?: string }
  >;
  isError?: boolean;
}

createSdkMcpServer(options)

Creates an SDK-embedded MCP server instance.

Option	Type	Default	Description
name	string	Required	Unique name for the MCP server
version	string	'1.0.0'	Server version
tools	SdkMcpToolDefinition[]	-	Array of tools created with tool()

Returns a McpSdkServerConfigWithInstance object that can be passed directly to the mcpServers option.

Example

import { z } from 'zod';
import { query, tool, createSdkMcpServer } from '@qwen-code/sdk';

// Define a tool with Zod schema
const calculatorTool = tool(
  'calculate_sum',
  'Add two numbers',
  { a: z.number(), b: z.number() },
  async (args) => ({
    content: [{ type: 'text', text: String(args.a + args.b) }],
  }),
);

// Create the MCP server
const server = createSdkMcpServer({
  name: 'calculator',
  tools: [calculatorTool],
});

// Use the server in a query
const result = query({
  prompt: 'What is 42 + 17?',
  options: {
    permissionMode: 'yolo',
    mcpServers: {
      calculator: server,
    },
  },
});

for await (const message of result) {
  console.log(message);
}

Abort a Query

import { query, isAbortError } from '@qwen-code/sdk';

const abortController = new AbortController();

const result = query({
  prompt: 'Long running task...',
  options: {
    abortController,
  },
});

// Abort after 5 seconds
setTimeout(() => abortController.abort(), 5000);

try {
  for await (const message of result) {
    console.log(message);
  }
} catch (error) {
  if (isAbortError(error)) {
    console.log('Query was aborted');
  } else {
    throw error;
  }
}

Error Handling

The SDK provides an AbortError class for handling aborted queries:

import { AbortError, isAbortError } from '@qwen-code/sdk';

try {
  // ... query operations
} catch (error) {
  if (isAbortError(error)) {
    // Handle abort
  } else {
    // Handle other errors
  }
}