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createDeepAgent has the following configuration options:
const agent = createDeepAgent({
  backend?: AnyBackendProtocol | (config: __type) => AnyBackendProtocol,
  checkpointer?: boolean | BaseCheckpointSaver<number>,
  contextSchema?: ContextSchema,
  interruptOn?: Record<string, boolean | __type>,
  memory?: string[],
  middleware?: TMiddleware,
  model?: string | BaseLanguageModel<any, BaseLanguageModelCallOptions>,
  name?: string,
  responseFormat?: TResponse,
  skills?: string[],
  store?: BaseStore,
  subagents?: TSubagents,
  systemPrompt?: string | SystemMessage<MessageStructure<MessageToolSet>>,
  tools?: TTools | StructuredTool<ToolInputSchemaBase, any, any, any, unknown>[]
});
For the full parameter list, see the createDeepAgent API reference.

Model

Pass a model string in provider:model format, or an initialized model instance. See supported models for all providers and suggested models for tested recommendations.
Use the provider:model format (for example openai:gpt-5.4) to quickly switch between models.
👉 Read the OpenAI chat model integration docs
npm install @langchain/openai deepagents
import { createDeepAgent } from "deepagents";

process.env.OPENAI_API_KEY = "your-api-key";

const agent = createDeepAgent({ model: "gpt-5.4" });
// this calls initChatModel for the specified model with default parameters
// to use specific model parameters, use initChatModel directly

Connection resilience

LangChain chat models automatically retry failed API requests with exponential backoff. By default, models retry up to 6 times for network errors, rate limits (429), and server errors (5xx). Client errors like 401 (unauthorized) or 404 are not retried. You can adjust the maxRetries parameter when creating a model to tune this behavior for your environment:
import { ChatAnthropic } from "@langchain/anthropic";
import { createDeepAgent } from "deepagents";

const agent = createDeepAgent({
    model: new ChatAnthropic({
        model: "claude-sonnet-4-6",
        maxRetries: 10, // Increase for unreliable networks (default: 6)
        timeout: 120_000, // Increase timeout for slow connections
    }),
});
For long-running agent tasks on unreliable networks, consider increasing max_retries to 10–15 and pairing it with a checkpointer so that progress is preserved across failures.

Tools

In addition to built-in tools for planning, file management, and subagent spawning, you can provide custom tools:
import { tool } from "langchain";
import { TavilySearch } from "@langchain/tavily";
import { createDeepAgent } from "deepagents";
import { z } from "zod";

const internetSearch = tool(
  async ({
    query,
    maxResults = 5,
    topic = "general",
    includeRawContent = false,
  }: {
    query: string;
    maxResults?: number;
    topic?: "general" | "news" | "finance";
    includeRawContent?: boolean;
  }) => {
    const tavilySearch = new TavilySearch({
      maxResults,
      tavilyApiKey: process.env.TAVILY_API_KEY,
      includeRawContent,
      topic,
    });
    return await tavilySearch._call({ query });
  },
  {
    name: "internet_search",
    description: "Run a web search",
    schema: z.object({
      query: z.string().describe("The search query"),
      maxResults: z.number().optional().default(5),
      topic: z
        .enum(["general", "news", "finance"])
        .optional()
        .default("general"),
      includeRawContent: z.boolean().optional().default(false),
    }),
  },
);

const agent = createDeepAgent({
  tools: [internetSearch],
});

System prompt

Deep Agents come with a built-in system prompt. A deep agent’s value comes from the orchestration layer the SDK provides on top of the model—planning, virtual-filesystem tools, and subagents—and the model needs to know those exist and when to reach for them. The built-in prompt teaches the agent how to use that scaffolding so you don’t have to re-derive it for every project; tweak it through a profile or your own system_prompt= rather than copying it verbatim. When middleware add special tools, like the filesystem tools, it appends them to the system prompt. Each deep agent should also include a custom system prompt specific to its specific use case:
import { createDeepAgent } from "deepagents";

const researchInstructions = `You are an expert researcher. ` +
  `Your job is to conduct thorough research, and then ` +
  `write a polished report.`;

const agent = createDeepAgent({
  systemPrompt: researchInstructions,
});

Prompt assembly

Deep Agents builds the system prompt from up to four named parts so that caller-supplied instructions, the SDK’s built-in agent guidance, and any model-specific profile overrides can coexist with predictable precedence. Without this layering, a profile suffix tuned for Claude (for example) could overwrite or be overwritten by your system_prompt= argument depending on call order; the named slots make the ordering explicit and stable. In practice, most callers only encounter two slots: USER (your system_prompt=) and BASE (the SDK default). Selecting a model with a built-in profile—Anthropic or OpenAI today—adds a SUFFIX. The full four-part assembly is mainly relevant when you author a custom HarnessProfile or debug why a profile’s text appears where it does. The four named parts (each may be absent):
NameSourceNotes
USERsystem_prompt= argument to create_deep_agentstr or SystemMessage; omitted when unset.
BASEThe SDK default (BASE_AGENT_PROMPT)Always present unless replaced by a profile’s CUSTOM.
CUSTOMHarnessProfile.base_system_promptReplaces BASE outright when a matching profile sets it.
SUFFIXHarnessProfile.system_prompt_suffixAppended last when a matching profile sets it.
The order is always USER -> (BASE or CUSTOM) -> SUFFIX, joined by blank lines (\n\n). Two invariants follow:
  1. USER is always at the front. The caller’s text precedes any SDK or profile content, so persona/instructions take precedence regardless of which model is selected.
  2. SUFFIX is always at the end. Profile suffixes sit closest to the conversation history, where model-tuning guidance lands most reliably.
Assembled shapes (✓ = field is set, - = field is unset):
system_prompt=profile base_system_prompt (CUSTOM)profile system_prompt_suffix (SUFFIX)Final assembled system prompt
None--BASE
None-BASE + SUFFIX
None-CUSTOM
NoneCUSTOM + SUFFIX
str--USER + BASE
str-USER + BASE + SUFFIX
str-USER + CUSTOM
strUSER + CUSTOM + SUFFIX
Worked example — built-in profiles (Anthropic, OpenAI) ship only a system_prompt_suffix, so a typical call lands in the str + - + row:
agent = create_deep_agent(
    model="anthropic:claude-sonnet-4-6",
    system_prompt="You are a customer-support agent for ACME Corp.",
)
# Final = USER + BASE + SUFFIX
#       = "You are a customer-support agent for ACME Corp."
#         + "\n\n"
#         + BASE_AGENT_PROMPT
#         + "\n\n"
#         + <Claude-specific guidance>
Passing a SystemMessage (rather than a string) triggers a different concatenation path: the right-hand assembly (BASE-or-CUSTOM plus any SUFFIX) is appended as an additional text content block onto the message’s existing content_blocks. The same logical ordering applies (caller blocks first), and any cache_control markers on the caller’s blocks are preserved — useful for placing explicit Anthropic prompt-cache breakpoints.
The same overlay rules apply to declarative subagents — each subagent re-runs profile resolution against its own model, then applies the resolved profile’s base_system_prompt / system_prompt_suffix to its authored system_prompt. The subagent’s system_prompt plays the BASE role; CUSTOM and SUFFIX come from the profile that matches the subagent’s model (which may differ from the main agent’s profile).
spec["system_prompt"]profile base_system_prompt (CUSTOM)profile system_prompt_suffix (SUFFIX)Final subagent system prompt
authored--authored
authored-authored + SUFFIX
authored-CUSTOM
authoredCUSTOM + SUFFIX
There is no USER segment for subagents — the spec’s authored system_prompt is the closest analog and stays in the BASE slot. A profile that ships only a system_prompt_suffix (the common case for built-in Anthropic / OpenAI profiles) just appends to whatever the subagent author wrote; a profile that sets base_system_prompt will replace the authored prompt outright, so reach for that field deliberately.
The auto-added general-purpose subagent follows the same overlay rules with one extra layer: the GP base prompt is resolved as general_purpose_subagent.system_prompt (if set) -> HarnessProfile.base_system_prompt (if set) -> SDK GP default. The profile suffix layers on top either way.The two override fields can both carry a base-prompt replacement, but they are not interchangeable. general_purpose_subagent.system_prompt is GP-specific configuration; base_system_prompt is a global override that primarily targets the main agent. When both are set, the GP-specific intent wins for the GP subagent so a user tuning both fields never sees their GP override silently dropped:
register_harness_profile(
    "anthropic",
    HarnessProfile(
        base_system_prompt="You are ACME's support orchestrator.",  # main agent
        general_purpose_subagent=GeneralPurposeSubagentProfile(
            system_prompt="You are a research subagent. Cite sources.",  # GP subagent
        ),
        system_prompt_suffix="Always think step by step.",
    ),
)
StackFinal system prompt
Main agent"You are ACME's support orchestrator." + SUFFIX
GP subagent"You are a research subagent. Cite sources." + SUFFIX
If general_purpose_subagent.system_prompt is unset, the GP subagent falls back to base_system_prompt (when set) and finally to the SDK GP default.

Middleware

By default, Deep Agents have access to the following middleware: If you are using memory, skills, or human-in-the-loop, the following middleware is also included:
  • MemoryMiddleware: Persists and retrieves conversation context across sessions when the memory argument is provided
  • SkillsMiddleware: Enables custom skills when the skills argument is provided
  • HumanInTheLoopMiddleware: Pauses for human approval or input at specified points when the interruptOn argument is provided

Prebuilt middleware

LangChain exposes additional prebuilt middleware that let you add-on various features, such as retries, fallbacks, or PII detection. See Prebuilt middleware for more. The deepagents package also exposes createSummarizationMiddleware for the same workflow. For more detail, see Summarization.

Provider-specific middleware

For provider-specific middleware that is optimized for specific LLM providers, see Official integrations and Community integrations.

Custom middleware

You can provide additional middleware to extend functionality, add tools, or implement custom hooks:
import { tool, createMiddleware } from "langchain";
import { createDeepAgent } from "deepagents";
import * as z from "zod";

const getWeather = tool(
  ({ city }: { city: string }) => {
    return `The weather in ${city} is sunny.`;
  },
  {
    name: "get_weather",
    description: "Get the weather in a city.",
    schema: z.object({
      city: z.string(),
    }),
  }
);

let callCount = 0;

const logToolCallsMiddleware = createMiddleware({
  name: "LogToolCallsMiddleware",
  wrapToolCall: async (request, handler) => {
    // Intercept and log every tool call - demonstrates cross-cutting concern
    callCount += 1;
    const toolName = request.toolCall.name;

    console.log(`[Middleware] Tool call #${callCount}: ${toolName}`);
    console.log(
      `[Middleware] Arguments: ${JSON.stringify(request.toolCall.args)}`
    );

    // Execute the tool call
    const result = await handler(request);

    // Log the result
    console.log(`[Middleware] Tool call #${callCount} completed`);

    return result;
  },
});

const agent = await createDeepAgent({
  model: "google_genai:gemini-3.1-pro-preview",
  tools: [getWeather] as any,
  middleware: [logToolCallsMiddleware] as any,
});
Do not mutate attributes after initializationIf you need to track values across hook invocations (for example, counters or accumulated data), use graph state. Graph state is scoped to a thread by design, so updates are safe under concurrency.Do this:
const customMiddleware = createMiddleware({
  name: "CustomMiddleware",
  beforeAgent: async (state) => {
    return { x: (state.x ?? 0) + 1 }; // Update graph state instead
  },
});
Do not do this:
let x = 1;

const customMiddleware = createMiddleware({
  name: "CustomMiddleware",
  beforeAgent: async () => {
    x += 1; // Mutation causes race conditions
  },
});
Mutation in place, such as modifying state.x in beforeAgent, mutating a shared variable in beforeAgent, or changing other shared values in hooks, can lead to subtle bugs and race conditions because many operations run concurrently (subagents, parallel tools, and parallel invocations on different threads).For full details on extending state with custom properties, see Custom middleware - Custom state schema. If you must use mutation in custom middleware, consider what happens when subagents, parallel tools, or concurrent agent invocations run at the same time.

Subagents

To isolate detailed work and avoid context bloat, use subagents:
import { tool } from "langchain";
import { TavilySearch } from "@langchain/tavily";
import { createDeepAgent, type SubAgent } from "deepagents";
import { z } from "zod";

const internetSearch = tool(
  async ({
    query,
    maxResults = 5,
    topic = "general",
    includeRawContent = false,
  }: {
    query: string;
    maxResults?: number;
    topic?: "general" | "news" | "finance";
    includeRawContent?: boolean;
  }) => {
    const tavilySearch = new TavilySearch({
      maxResults,
      tavilyApiKey: process.env.TAVILY_API_KEY,
      includeRawContent,
      topic,
    });
    return await tavilySearch._call({ query });
  },
  {
    name: "internet_search",
    description: "Run a web search",
    schema: z.object({
      query: z.string().describe("The search query"),
      maxResults: z.number().optional().default(5),
      topic: z
        .enum(["general", "news", "finance"])
        .optional()
        .default("general"),
      includeRawContent: z.boolean().optional().default(false),
    }),
  },
);

const researchSubagent: SubAgent = {
  name: "research-agent",
  description: "Used to research more in depth questions",
  systemPrompt: "You are a great researcher",
  tools: [internetSearch],
  model: "openai:gpt-5.4",  // Optional override, defaults to main agent model
};
const subagents = [researchSubagent];

const agent = createDeepAgent({
  model: "claude-sonnet-4-6",
  subagents,
});
For more information, see Subagents.

Backends

Tools for a deep agent can make use of virtual file systems to store, access, and edit files. By default, deep agents use a StateBackend. If you are using skills or memory, you must add the expected skill or memory files to the backend before creating the agent.
An ephemeral filesystem backend stored in langgraph state.This filesystem only persists for a single thread.
import { createDeepAgent, StateBackend } from "deepagents";

// By default we provide a StateBackend
const agent = createDeepAgent();

// Under the hood, it looks like
const agent2 = createDeepAgent({
  backend: new StateBackend(),
});
For more information, see Backends.

Sandboxes

Sandboxes are specialized backends that run agent code in an isolated environment with their own filesystem and an execute tool for shell commands. Use a sandbox backend when you want your deep agent to write files, install dependencies, and run commands without changing anything on your local machine. You configure sandboxes by passing a sandbox backend to backend when creating your deep agent:
import { createDeepAgent } from "deepagents";
import { ChatAnthropic } from "@langchain/anthropic";
import { DenoSandbox } from "@langchain/deno";

// Create and initialize the sandbox
const sandbox = await DenoSandbox.create({
  memoryMb: 1024,
  lifetime: "10m",
});

try {
  const agent = createDeepAgent({
    model: new ChatAnthropic({ model: "claude-opus-4-6" }),
    systemPrompt: "You are a JavaScript coding assistant with sandbox access.",
    backend: sandbox,
  });

  const result = await agent.invoke({
    messages: [
      {
        role: "user",
        content:
          "Create a simple HTTP server using Deno.serve and test it with curl",
      },
    ],
  });
} finally {
  await sandbox.close();
}
For more information, see Sandboxes.

Human-in-the-loop

Some tool operations may be sensitive and require human approval before execution. You can configure the approval for each tool:
import { tool } from "langchain";
import { createDeepAgent } from "deepagents";
import { MemorySaver } from "@langchain/langgraph";
import { z } from "zod";

const deleteFile = tool(
  async ({ path }: { path: string }) => {
    return `Deleted ${path}`;
  },
  {
    name: "delete_file",
    description: "Delete a file from the filesystem.",
    schema: z.object({
      path: z.string(),
    }),
  },
);

const readFile = tool(
  async ({ path }: { path: string }) => {
    return `Contents of ${path}`;
  },
  {
    name: "read_file",
    description: "Read a file from the filesystem.",
    schema: z.object({
      path: z.string(),
    }),
  },
);

const sendEmail = tool(
  async ({ to, subject, body }: { to: string; subject: string; body: string }) => {
    return `Sent email to ${to}`;
  },
  {
    name: "send_email",
    description: "Send an email.",
    schema: z.object({
      to: z.string(),
      subject: z.string(),
      body: z.string(),
    }),
  },
);

// Checkpointer is REQUIRED for human-in-the-loop
const checkpointer = new MemorySaver();

const agent = createDeepAgent({
  model: "google_genai:gemini-3.1-pro-preview",
  tools: [deleteFile, readFile, sendEmail],
  interruptOn: {
    delete_file: true,  // Default: approve, edit, reject
    read_file: false,   // No interrupts needed
    send_email: { allowedDecisions: ["approve", "reject"] },  // No editing
  },
  checkpointer,  // Required!
});
You can configure interrupt for agents and subagents on tool call as well as from within tool calls. For more information, see Human-in-the-loop.

Skills

You can use skills to provide your deep agent with new capabilities and expertise. While tools tend to cover lower level functionality like native file system actions or planning, skills can contain detailed instructions on how to complete tasks, reference info, and other assets, such as templates. These files are only loaded by the agent when the agent has determined that the skill is useful for the current prompt. This progressive disclosure reduces the amount of tokens and context the agent has to consider upon startup. For example skills, see Deep Agents example skills. To add skills to your deep agent, pass them as an argument to create_deep_agent:
import { createDeepAgent, type FileData } from "deepagents";
import { MemorySaver } from "@langchain/langgraph";

const checkpointer = new MemorySaver();

function createFileData(content: string): FileData {
  const now = new Date().toISOString();
  return {
    content: content.split("\n"),
    created_at: now,
    modified_at: now,
  };
}

const skillsFiles: Record<string, FileData> = {};

const skillUrl =
  "https://raw.githubusercontent.com/langchain-ai/deepagentsjs/refs/heads/main/examples/skills/langgraph-docs/SKILL.md";
const response = await fetch(skillUrl);
const skillContent = await response.text();

skillsFiles["/skills/langgraph-docs/SKILL.md"] = createFileData(skillContent);

const agent = await createDeepAgent({
  checkpointer,
  // IMPORTANT: deepagents skill source paths are virtual (POSIX) paths relative to the backend root.
  skills: ["/skills/"],
});

const config = {
  configurable: {
    thread_id: `thread-${Date.now()}`,
  },
};

const result = await agent.invoke(
  {
    messages: [
      {
        role: "user",
        content: "what is langraph? Use the langgraph-docs skill if available.",
      },
    ],
    files: skillsFiles,
  },
  config,
);

Memory

Use AGENTS.md files to provide extra context to your deep agent. You can pass one or more file paths to the memory parameter when creating your deep agent:
import { createDeepAgent, type FileData } from "deepagents";
import { MemorySaver } from "@langchain/langgraph";

const AGENTS_MD_URL =
  "https://raw.githubusercontent.com/langchain-ai/deepagents/refs/heads/main/examples/text-to-sql-agent/AGENTS.md";

async function fetchText(url: string): Promise<string> {
  const res = await fetch(url);
  if (!res.ok) {
    throw new Error(`Failed to fetch ${url}: ${res.status} ${res.statusText}`);
  }
  return await res.text();
}

const agentsMd = await fetchText(AGENTS_MD_URL);
const checkpointer = new MemorySaver();

function createFileData(content: string): FileData {
  const now = new Date().toISOString();
  return {
    content,
    mimeType: "text/plain",
    created_at: now,
    modified_at: now,
  };
}

const agent = await createDeepAgent({
  memory: ["/AGENTS.md"],
  checkpointer: checkpointer,
});

const result = await agent.invoke(
  {
    messages: [
      {
        role: "user",
        content: "Please tell me what's in your memory files.",
      },
    ],
    // Seed the default StateBackend's in-state filesystem (virtual paths must start with "/").
    files: { "/AGENTS.md": createFileData(agentsMd) },
  },
  { configurable: { thread_id: "12345" } }
);

Profiles

A harness profile packages per-provider or per-model tweaks (system prompt suffixes, tool description overrides, excluded tools or middleware, extra middleware, and general-purpose subagent edits) so create_deep_agent applies them automatically when the matching model is selected.
from deepagents import HarnessProfile, register_harness_profile

# Append a system-prompt suffix whenever gpt-5.4 is selected.
register_harness_profile(
    "openai:gpt-5.4",
    HarnessProfile(system_prompt_suffix="Respond in under 100 words."),
)
See Profiles for registration keys, merge semantics, and plugin packaging. A narrower companion API, provider profiles, packages model-construction arguments for a provider.

Structured output

Deep Agents support structured output. You can set a desired structured output schema by passing it as the responseFormat argument to the call to createDeepAgent(). When the model generates the structured data, it’s captured, validated, and returned in the ‘structuredResponse’ key of the agent’s state.
import { tool } from "langchain";
import { TavilySearch } from "@langchain/tavily";
import { createDeepAgent } from "deepagents";
import { z } from "zod";

const internetSearch = tool(
  async ({
    query,
    maxResults = 5,
    topic = "general",
    includeRawContent = false,
  }: {
    query: string;
    maxResults?: number;
    topic?: "general" | "news" | "finance";
    includeRawContent?: boolean;
  }) => {
    const tavilySearch = new TavilySearch({
      maxResults,
      tavilyApiKey: process.env.TAVILY_API_KEY,
      includeRawContent,
      topic,
    });
    return await tavilySearch._call({ query });
  },
  {
    name: "internet_search",
    description: "Run a web search",
    schema: z.object({
      query: z.string().describe("The search query"),
      maxResults: z.number().optional().default(5),
      topic: z
        .enum(["general", "news", "finance"])
        .optional()
        .default("general"),
      includeRawContent: z.boolean().optional().default(false),
    }),
  }
);

const weatherReportSchema = z.object({
  location: z.string().describe("The location for this weather report"),
  temperature: z.number().describe("Current temperature in Celsius"),
  condition: z
    .string()
    .describe("Current weather condition (e.g., sunny, cloudy, rainy)"),
  humidity: z.number().describe("Humidity percentage"),
  windSpeed: z.number().describe("Wind speed in km/h"),
  forecast: z.string().describe("Brief forecast for the next 24 hours"),
});

const agent = await createDeepAgent({
  responseFormat: weatherReportSchema,
  tools: [internetSearch],
});

const result = await agent.invoke({
  messages: [
    {
      role: "user",
      content: "What's the weather like in San Francisco?",
    },
  ],
});

console.log(result.structuredResponse);
// {
//   location: 'San Francisco, California',
//   temperature: 18.3,
//   condition: 'Sunny',
//   humidity: 48,
//   windSpeed: 7.6,
//   forecast: 'Clear skies with temperatures remaining mild. High of 18°C (64°F) during the day, dropping to around 11°C (52°F) at night.'
// }
For more information and examples, see response format. n and examples, see response format.