@cellar-door/langchain

𓉸 Passage Protocol · exit-door · entry-door · mcp · langchain · vercel · eliza · eas · erc-8004 · sign · python

⚠️ Pre-release software — no formal security audit has been conducted. This project is published for transparency, review, and community feedback. It should not be used in production systems where security guarantees are required. If you find a vulnerability, please report it to [email protected].

Add verifiable departure and arrival records to your LangChain agents.

Ecosystem

| Package | Language | Description | |---------|----------|-------------| | cellar-door-exit | TypeScript | Core protocol (reference impl) | | cellar-door-exit | Python | Core protocol | | cellar-door-entry | TypeScript | Arrival/entry markers | | @cellar-door/langchain | TypeScript | LangChain integration ← you are here | | cellar-door-langchain | Python | LangChain integration | | @cellar-door/vercel-ai-sdk | TypeScript | Vercel AI SDK | | @cellar-door/mcp-server | TypeScript | MCP server | | @cellar-door/eliza | TypeScript | ElizaOS plugin | | @cellar-door/eas | TypeScript | EAS attestation anchoring | | @cellar-door/erc-8004 | TypeScript | ERC-8004 identity/reputation | | @cellar-door/sign-protocol | TypeScript | Sign Protocol attestation |

Paper · Website

Quick Start

npm install @cellar-door/langchain @langchain/core cellar-door-exit cellar-door-entry

import { createExitTool } from "@cellar-door/langchain";

// Add to any LangChain agent
const exitTool = createExitTool();

// The agent can now create signed EXIT markers:
// "Create a departure record for did:web:platform.example"
// → Returns a signed, verifiable EXIT marker

Automatic EXIT on chain completion

import { ExitCallbackHandler } from "@cellar-door/langchain";

const handler = new ExitCallbackHandler({
  origin: "my-app",
  onMarker: (marker) => console.log("Departed:", marker.id),
});

const result = await chain.invoke(input, { callbacks: [handler] });
// EXIT marker created automatically when the chain finishes

EXIT Tools

Exit Tool

import { createExitTool } from "@cellar-door/langchain";

const tool = createExitTool();
// Use with any LangChain agent

Exit Callback Handler

import { ExitCallbackHandler } from "@cellar-door/langchain";

const handler = new ExitCallbackHandler({
  origin: "my-app",
  onMarker: (marker) => console.log("Departed:", marker.id),
});

ENTRY Tools

Entry Tool

import { createEntryTool } from "@cellar-door/langchain";

const entryTool = createEntryTool();
// Agent calls with { exitMarkerJson, destination }
// Returns signed arrival marker with continuity verification

Admission Policy Tool

import { createAdmissionPolicyTool } from "@cellar-door/langchain";

const admissionTool = createAdmissionPolicyTool();
// Agent calls with { exitMarkerJson, policy: "OPEN_DOOR" | "STRICT" | "EMERGENCY_ONLY" }

Transfer Verification Tool

import { createTransferVerificationTool } from "@cellar-door/langchain";

const transferTool = createTransferVerificationTool();
// Agent calls with { exitMarkerJson, arrivalMarkerJson }
// Returns { verified, transferTime, errors, continuity }

Callback Handler with Arrival

import { ExitCallbackHandler } from "@cellar-door/langchain";

const handler = new ExitCallbackHandler({
  origin: "platform-a",
  arrivalDestination: "platform-b",
  onMarker: (marker) => console.log("EXIT:", marker.id),
  onArrival: (arrival) => console.log("ARRIVAL:", arrival.id),
});

// handler.markers — all EXIT markers
// handler.arrivals — all ARRIVAL markers

API

EXIT

• createExitTool(opts?) — DynamicStructuredTool for creating EXIT markers
• ExitCallbackHandler — Callback handler for automatic EXIT (and optionally ENTRY) markers

ENTRY

• createEntryTool() — Tool to verify EXIT + create arrival
• createAdmissionPolicyTool() — Tool to evaluate admission policies
• createTransferVerificationTool() — Tool to verify EXIT→ENTRY transfers

⚠️ Disclaimer

WARNING: Automated admission decisions should be reviewed by platform operators. This integration does not constitute legal advice. Platforms are responsible for their own admission policies and the consequences of admitting agents.

License

Apache-2.0