What types of physical mail can I send with Lob?

Lob supports three main mail types: Letters (formal correspondence, invoices, notifications with customizable color, double-sided printing), Postcards (marketing campaigns, invitations, reminders in 4x6, 6x9, or 6x11 sizes), and Checks (vendor payments, payroll, refunds, rebates with customizable memo lines and company logos). All mail is printed and mailed within 24 hours via USPS.

How does Lob address verification work?

Lob's address verification validates and standardizes addresses using USPS data. It corrects formatting, adds missing ZIP+4 codes, fixes typos, and confirms deliverability. The service returns a deliverability status: 'deliverable' (valid and deliverable), 'undeliverable' (cannot be delivered), or 'deliverable_unnecessary' (valid but additional info not needed). This reduces returned mail by up to 5% and ensures your mailings reach the correct destination.

Can I use HTML templates for personalized mailings?

Yes! Lob supports HTML templates with merge variables using the Handlebars templating engine. Create a template with placeholders like {{name}}, {{order_number}}, {{delivery_date}}, then pass actual values when creating letters or postcards. This enables personalized, scalable direct mail campaigns. Templates are reusable and can be referenced by ID when creating mailings. You can also embed CSS styling for professional-looking mail designs.

How long does it take for mail to be delivered?

Lob prints and mails all items within 24 hours of creation. Delivery time depends on the mail type selected: USPS First Class Mail typically delivers in 2-5 business days, while USPS Standard Mail takes 3-7 business days. You receive a tracking number for each piece of mail to monitor delivery status. Lob also provides expected delivery dates in API responses for planning purposes.

Lob MCP Server for OpenAI Agents SDK 21 tools — connect in under 2 minutes

Name: Lob
Availability: InStock
Author: Vinkius

openai.github.io/openai-agents-python/mcp

Built by Vinkius GDPR 21 Tools SDK

The OpenAI Agents SDK enables production-grade agent workflows in Python. Connect Lob through the Vinkius and your agents gain typed, auto-discovered tools with built-in guardrails — no manual schema definitions required.

Get MCP Server for AI Agents

ASK AI ABOUT THIS MCP SERVER

Open in ChatGPT Open in Claude Open in Perplexity

Vinkius supports streamable HTTP and SSE.

python

import asyncio
from agents import Agent, Runner
from agents.mcp import MCPServerStreamableHttp

async def main():
    # Your Vinkius token — get it at cloud.vinkius.com
    async with MCPServerStreamableHttp(
        url="https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"
    ) as mcp_server:

        agent = Agent(
            name="Lob Assistant",
            instructions=(
                "You help users interact with Lob. "
                "You have access to 21 tools."
            ),
            mcp_servers=[mcp_server],
        )

        result = await Runner.run(
            agent, "List all available tools from Lob"
        )
        print(result.final_output)

asyncio.run(main())

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Stream every event to Splunk, Datadog, or your own webhook in real-time

* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure

About Lob MCP Server

Lob MCP Server enables AI agents to send physical mail directly from your applications. Create and mail letters, postcards, and checks programmatically through Lob's print and mail API. Verify US and international addresses, autocomplete partial addresses, and manage your address book. Build reusable HTML templates for personalized mailings. Perfect for automating vendor payments, customer communications, marketing campaigns, payroll checks, and direct mail operations. All mail is printed, processed, and delivered within 24 hours via USPS integration.

The OpenAI Agents SDK auto-discovers all 21 tools from Lob through native MCP integration. Build agents with built-in guardrails, tracing, and handoff patterns — chain multiple agents where one queries Lob, another analyzes results, and a third generates reports, all orchestrated through the Vinkius.

The Lob MCP Server exposes 21 tools through the Vinkius. Connect it to OpenAI Agents SDK in under two minutes — no API keys to rotate, no infrastructure to provision, no vendor lock-in. Your configuration, your data, your control.

How to Connect Lob to OpenAI Agents SDK via MCP

Follow these steps to integrate the Lob MCP Server with OpenAI Agents SDK.

Install the SDK

Run pip install openai-agents in your Python environment

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token from cloud.vinkius.com

Run the script

Save the code above and run it: python agent.py

Explore tools

The agent will automatically discover 21 tools from Lob

Why Use OpenAI Agents SDK with the Lob MCP Server

OpenAI Agents SDK provides unique advantages when paired with Lob through the Model Context Protocol.

Native MCP integration via `MCPServerSse` — pass the URL and the SDK auto-discovers all tools with full type safety

Built-in guardrails, tracing, and handoff patterns let you build production-grade agents without reinventing safety infrastructure

Lightweight and composable: chain multiple agents and MCP servers in a single pipeline with minimal boilerplate

First-party OpenAI support ensures optimal compatibility with GPT models for tool calling and structured output

Lob + OpenAI Agents SDK Use Cases

Practical scenarios where OpenAI Agents SDK combined with the Lob MCP Server delivers measurable value.

Automated workflows: build agents that query Lob, process the data, and trigger follow-up actions autonomously

Multi-agent orchestration: create specialist agents — one queries Lob, another analyzes results, a third generates reports

Data enrichment pipelines: stream data through Lob tools and transform it with OpenAI models in a single async loop

Customer support bots: agents query Lob to resolve tickets, look up records, and update statuses without human intervention

Lob MCP Tools for OpenAI Agents SDK (21)

These 21 tools become available when you connect Lob to OpenAI Agents SDK via MCP:

autocomplete_us_address

Autocomplete a partial US address

cancel_letter

Only works if status is still "processing". Cancel a letter before it enters production

create_address

Requires name and address_line1. Create a new address in your Lob address book

create_bank_account

Requires description, routing_number, account_number, account_type (company/individual), and signatory. Add a bank account for sending checks

create_check

Requires recipient (to), bank account ID, and amount. Optional: memo, logo, description. Create and mail a physical check through Lob

create_letter

Requires recipient (to), sender (from), and file content. Supports HTML templates with merge variables, color options, and mail type selection. Create and mail a physical letter through Lob

create_postcard

Requires recipient (to) and front design. Optional: back design, message, merge variables. Create and mail a physical postcard through Lob

create_template

Create a reusable HTML template for mailings

delete_address

Delete an address from your Lob address book

get_address

Get details of a specific address

get_check

Get details of a specific check by ID

get_letter

Get details of a specific letter by ID

get_postcard

Get details of a specific postcard by ID

get_template

Get details of a specific template

list_addresses

Use optional limit to control result count. List addresses in your Lob address book

list_bank_accounts

Use optional limit to control result count. List bank accounts in your Lob account

list_checks

Track payments, audit disbursements. List physical checks sent through Lob

list_letters

Each letter includes status, tracking number, and expected delivery date. Use optional limit to control result count. List physical letters sent through Lob. Track mailings, check delivery status, and review letter history

list_postcards

Use optional limit to control result count. List physical postcards sent through Lob

list_templates

List HTML templates for mailings

verify_us_address

Verify and standardize a US address

Example Prompts for Lob in OpenAI Agents SDK

Ready-to-use prompts you can give your OpenAI Agents SDK agent to start working with Lob immediately.

"Send a letter to John Doe at 123 Main St, New York, NY 10001 with our welcome package HTML template"

"Verify if this address is deliverable: 185 Berry St, San Francisco, CA 94107"

"Send a $500 check to ABC Consulting for consulting services rendered in March"

Troubleshooting Lob MCP Server with OpenAI Agents SDK

Common issues when connecting Lob to OpenAI Agents SDK through the Vinkius, and how to resolve them.

MCPServerStreamableHttp not found

Ensure you have the latest version: pip install --upgrade openai-agents

Agent not calling tools

Make sure your prompt explicitly references the task the tools can help with.

Lob + OpenAI Agents SDK FAQ

Common questions about integrating Lob MCP Server with OpenAI Agents SDK.

How does the OpenAI Agents SDK connect to MCP?

Use MCPServerSse(url=...) to create a server connection. The SDK auto-discovers all tools and makes them available to your agent with full type information.