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How to connect Lob to Claude

Connect Claude Web, Desktop and Cowork to Lob MCP. Send a postcard to a verified address, validate this list of mailing addresses, and more using natural language, with authentication handled for you.

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Lob is a direct mail automation and address verification platform for businesses. It streamlines sending physical mail and validating addresses at scale with a simple API.

13 Tools

Introduction

Claude is Anthropic's AI assistant, available on the web, in the desktop app, and on mobile. Cowork is its agent for knowledge work, and it runs on all of those surfaces too. Connected to your apps, Claude can work with your files and services to accomplish complex tasks on your behalf.

This guide walks you through the easiest and most secure way to connect your Lob account to Claude via Composio Connect, enabling it to send a postcard to a verified address, validate this list of mailing addresses, track delivery status for recent letters, and more such actions on your behalf without compromising your account security.

Setup is the same on Claude Web, Desktop, and Cowork, and you only need to do it once. The connector is tied to your account, so it's available in all three.

Also integrate Lob with

Claude CodeOpenAI Agents SDKClaude Agent SDKCodexOpenClawHermesAtomic AgentGoogle ADKLangChainVercel AI SDKMastra AILlamaIndexCrewAIPydantic AIAutoGen

Connecting Lob to Claude Web, Desktop, and Cowork

Two ways to add the Composio connector. Pick whichever you prefer.

1. Add with one click

Click the button. Claude opens with the Composio connector filled in. Click Add, then go to step 2.

Add to Claude

Add manually

In Claude Desktop, click Customize in the left sidebar, then select Connectors and click the + icon at the top.

Claude Desktop connectors screen with Add custom connector selected

Click Add custom connector and paste in the Composio MCP server URL:

bash
https://connect.composio.dev/mcp
Add custom connector dialog with Composio MCP server URL

2. Authorize in your browser

Click Connect. You'll be redirected to a browser window where you can authorize Composio to continue.

Composio authorization screen for Claude Web, Desktop, and Cowork

3. Connect your Lob account

Back in Claude, ask it to connect to Lob or give it any Lob-related task.

For example, ask Claude to:

  • "Send a postcard to a verified address"
  • "Validate this list of mailing addresses"
  • "Track delivery status for recent letters"

It will prompt you to authenticate and authorize access.

That's it. Composio's tools are now available in Claude, and your Lob account is ready to use.

What is the Lob Claude Connector, and what's possible with it?

The Lob MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Lob account. It provides structured and secure access so your agent can perform Lob operations on your behalf.

Troubleshooting

1. Why does Claude not use the Composio connector for Lob?

The connector can show as connected, but Claude must use it in each Lob conversation.

  • Click + at the lower left of the chat, or type /.
  • Hover Connectors.
  • Turn on Composio.
  • Ask Claude to connect to Lob again.

2. Why does Claude show an MCP server error before Lob connects?

Claude can show Couldn't reach the MCP server or Authorization with the MCP server failed when you add the connector for Lob.

  • Check that the connector URL is https://connect.composio.dev/mcp.
  • Connectors run from Anthropic's cloud, so your device network is usually not the problem.
  • Add the connector again from Customize > Connectors, then ask Claude to connect Lob.
  • If it fails again, send the error and the ofid_ reference id to support@composio.dev.

3. Why does the Lob authorization link not work?

The Composio connector is one server. Your Lob account connects separately when Claude asks for it.

  • If the browser does not open, or the link expires, ask Claude to retry the Lob connection.
  • Composio creates a fresh Lob authorization link.
  • Open that link in your browser and finish the Lob sign-in.

4. Why do Lob actions fail after they worked before?

The Lob connection can expire or lose permission.

  • Ask Claude to inspect the Lob connection.
  • If the connection is unhealthy, disconnect it when Claude prompts you.
  • Reconnect the Lob account and retry the action.
  • If Claude shows a permission prompt, approve it before Claude changes data in Lob.
  • If the action still fails with a permission error, check that the connected account has that permission in Lob itself.

5. How do I switch to a different Lob account?

Claude can manage the Lob connection for you.

  • Ask Claude to disconnect or delete the current Lob account.
  • Ask Claude to connect Lob again.
  • Open the new Composio authorization link for Lob.
  • Sign in with the other Lob account in the browser.
  • After the account connects, ask Claude to retry the Lob task.

6. Why is my Lob connection missing in Claude Desktop or on a Team plan?

The connector belongs to your Claude account, so your Lob connection works in Claude Web, Desktop, and Cowork.

  • In Claude Desktop, open Customize > Connectors.
  • Next to Composio, click ⋮ and click Clear cache.
  • If Lob tools still do not appear, click ⋮, disconnect, remove the connector, and add it again.
  • On Team or Enterprise, an Owner or Primary Owner must enable the connector before you can connect Lob.
TOOLS

Supported Tools

Every Lob action and event your agent gets out of the box.

Create Domain

Tool to add a new custom domain for creating custom links.

Create Link

Tool to create a shortened URL from a long URL using Lob's link shortening service.

Delete Domain

Tool to delete a registered domain.

Delete Link

Tool to delete a shortened link.

Delete Upload

Tool to delete an existing upload by its unique identifier.

Get Domain

Tool to retrieve details for a single domain from Lob.

Get Link

Tool to retrieve a single shortened link.

List Domains

Tool to retrieve a list of all created domains.

List Shortened Links

Tool to retrieve a list of shortened links.

List QR Code Analytics

Tool to retrieve a list of your QR codes and their analytics data.

List Uploads

Tool to list uploads from Lob.

Update Link

Tool to update any properties of a shortened link.

Validate Identity

Tool to validate whether a given name is associated with an address.

FRAMEWORKS

How to build Lob MCP Agent with another framework

Claude Code logo

Claude Code

Use Lob MCP with Claude Code

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Lob MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Lob MCP with Claude Agent SDK

Codex logo

Codex

Use Lob MCP with Codex

OpenClaw logo

OpenClaw

Use Lob MCP with OpenClaw

Hermes logo

Hermes

Use Lob MCP with Hermes

Atomic Agent logo

Atomic Agent

Use Lob MCP with Atomic Agent

Google ADK logo

Google ADK

Use Lob MCP with Google ADK

LangChain logo

LangChain

Use Lob MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Lob MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Lob MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Lob MCP with LlamaIndex

CrewAI logo

CrewAI

Use Lob MCP with CrewAI

Pydantic AI logo

Pydantic AI

Use Lob MCP with Pydantic AI

AutoGen logo

AutoGen

Use Lob MCP with AutoGen

FAQ

Frequently asked questions

With a standalone Lob MCP server, the agents and LLMs can only access a fixed set of Lob tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Lob and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Claude Cowork fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Lob tools.

Yes, absolutely. You can configure which Lob scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Lob data and credentials are handled as safely as possible.

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