LangChain Reference home pageLangChain ReferenceLangChain Reference
  • GitHub
  • Main Docs
Deep Agents
LangChain
LangGraph
Integrations
LangSmith
  • Overview
  • Agent
  • Middleware
  • Backends
  • Sandboxes
  • Skills
  • Subagents
  • Types
Modal
Daytona
Deno
Node VFS
Sandbox Standard Tests
  • Vitest
⌘I

LangChain Assistant

Ask a question to get started

Enter to send•Shift+Enter new line

Menu

OverviewAgentMiddlewareBackendsSandboxesSkillsSubagentsTypes
Modal
Daytona
Deno
Node VFS
Sandbox Standard Tests
Vitest
Language
Theme
JavaScriptdeepagentsindexCreateDeepAgentParams
Interfaceā—Since v1.4

CreateDeepAgentParams

Configuration parameters for creating a Deep Agent Matches Python's create_deep_agent parameters

Copy
interface CreateDeepAgentParams

Properties

property
backend: AnyBackendProtocol | (config: __type) => AnyBackendProtocol

Backend instance or factory (default: StateBackend)

property
checkpointer: boolean | BaseCheckpointSaver<number>

Optional checkpointer for persisting agent state between runs

property
contextSchema: ContextSchema

Optional schema for context (not persisted between invocations)

property
interruptOn: Record<string, boolean | __type>

Human-in-the-loop configuration for specific tools. Requires a checkpointer.

property
memory: string[]

Optional list of memory file paths (AGENTS.md files) to load (e.g., ["~/.deepagents/AGENTS.md", "./.deepagents/AGENTS.md"]). Display names are automatically derived from paths. Memory is loaded at agent startup and added into the system prompt.

property
middleware: TMiddleware

Additional middleware to append after default_middleware

property
model: string | BaseLanguageModel<any, BaseLanguageModelCallOptions>

The model for the agent. Defaults to defaultModel

property
name: string

Error name for instanceof checks and logging

property
permissions: FilesystemPermission[]

Filesystem permission rules enforced on every tool call.

Rules are evaluated in declaration order; first match wins; permissive default. Applies to ls, read_file, write_file, edit_file, glob, and grep.

Note on execute: permissions are not enforced on execute because shell commands can access any path regardless of path-based rules. Using permissions with an execution-capable backend (one where isSandboxBackend returns true) throws a ConfigurationError unless either:

  • execute is disabled via tools, or
  • the backend is a CompositeBackend and every permission path is scoped to a route prefix.

When omitted or empty, all filesystem operations are permitted.

property
responseFormat: TResponse

Structured output response format for the subagent.

When specified, the subagent will produce a structuredResponse conforming to the given schema. The structured response is JSON-serialized and returned as the ToolMessage content to the parent agent, replacing the default last-message extraction.

Accepts any format supported by createAgent: Zod schemas, JSON schema objects, toolStrategy(schema), providerStrategy(schema), etc.

Copy
import { z } from "zod"

const analyzer: SubAgent = {
  name: "analyzer",
  description: "Analyzes data and returns structured findings",
  systemPrompt: "Analyze the data and return your findings.",
  responseFormat: z.object({
    findings: z.string(),
    confidence: z.number(),
  }),
};
property
skills: string[]

Skill source paths for SkillsMiddleware.

List of paths to skill directories (e.g., ["/skills/user/", "/skills/project/"]). When specified, the subagent will have its own SkillsMiddleware that loads skills from these paths. This allows subagents to have different skill sets than the main agent.

Note: Custom subagents do NOT inherit skills from the main agent by default. Only the general-purpose subagent inherits the main agent's skills.

Copy
const researcher: SubAgent = {
  name: "researcher",
  description: "Research assistant",
  systemPrompt: "You are a researcher.",
  skills: ["/skills/research/", "/skills/web-search/"],
};
property
stateSchema: TStateSchema

Optional schema for custom agent state. Allows you to define custom state properties beyond built-in messages, todos, and files. These properties can be accessed in hooks, middleware, and throughout the agent's execution.

Unlike contextSchema the state is persisted between agent invocations when using a checkpointer, making it suitable for maintaining conversation history, user preferences, or any other data that should persist across multiple interactions.

Copy
import { StateSchema } from "@langchain/langgraph";
import { z } from "zod";

const agent = createDeepAgent({
  stateSchema: new StateSchema({
    author: z.string().default("unknown"),
  }),
});

const result = await agent.invoke({
  messages: [{ role: "user", content: "Take a note" }],
  author: "Me",
});
// result.author is typed `string`
property
store: BaseStore

Optional BaseStore for persistent cross-conversation storage

property
streamTransformers: TStreamTransformers

Optional StreamTransformer factories to register with the underlying agent.

These are forwarded as-is to createAgent and their projections are exposed under run.extensions when using streamEvents(..., { version: "v3" }).

This is separate from the built-in streams createAgent provides on its own — such as run.subagents (nested named agents) and run.toolCalls (tool calls), which land directly on the run, not under run.extensions.

property
subagents: TSubagents

A list of additional subagents to provide to the agent

property
systemPrompt: string | SystemMessage<MessageStructure<MessageToolSet>> | SystemPromptConfig

System prompt override. Set to null to disable. Defaults to ASYNC_TASK_SYSTEM_PROMPT.

property
tools: TTools | StructuredTool<ToolInputSchemaBase, any, any, any, unknown>[]

Allowlist of built-in filesystem tools to expose to the model.

  • undefined, null, and "all" preserve the default behavior: every filesystem tool is registered, subject to backend capability filtering.
  • Passing an array restricts the middleware to only those tool names.
  • read_file must be included in every explicit array because it is used by normal file-inspection flows and by large-result recovery guidance.
  • Backend capability checks still narrow the final visible tool set. For example, execute is removed when the resolved backend does not support command execution, even if it appears in this allowlist.
  • User-provided non-filesystem tools are not affected by this allowlist.

The generated filesystem system prompt is based on the tools that remain visible after this allowlist and backend capability filtering are applied.

Copy
createFilesystemMiddleware({
  tools: ["read_file", "ls", "glob", "grep"],
});
View source on GitHub