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 CrewAI 21 tools — connect in under 2 minutes

Name: Lob
Availability: InStock
Author: Vinkius

docs.crewai.com/mcp/overview

Built by Vinkius GDPR 21 Tools Framework

Connect your CrewAI agents to Lob through Vinkius, pass the Edge URL in the `mcps` parameter and every Lob tool is auto-discovered at runtime. No credentials to manage, no infrastructure to maintain.

Get MCP Server for AI Agents

ASK AI ABOUT THIS MCP SERVER

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Vinkius supports streamable HTTP and SSE.

python

from crewai import Agent, Task, Crew

agent = Agent(
    role="Lob Specialist",
    goal="Help users interact with Lob effectively",
    backstory=(
        "You are an expert at leveraging Lob tools "
        "for automation and data analysis."
    ),
    # Your Vinkius token. get it at cloud.vinkius.com
    mcps=["https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"],
)

task = Task(
    description=(
        "Explore all available tools in Lob "
        "and summarize their capabilities."
    ),
    agent=agent,
    expected_output=(
        "A detailed summary of 21 available tools "
        "and what they can do."
    ),
)

crew = Crew(agents=[agent], tasks=[task])
result = crew.kickoff()
print(result)

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* 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.

When paired with CrewAI, Lob becomes a first-class tool in your multi-agent workflows. Each agent in the crew can call Lob tools autonomously, one agent queries data, another analyzes results, a third compiles reports, all orchestrated through Vinkius with zero configuration overhead.

The Lob MCP Server exposes 21 tools through the Vinkius. Connect it to CrewAI 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 CrewAI via MCP

Follow these steps to integrate the Lob MCP Server with CrewAI.

Install CrewAI

Run pip install crewai

Replace the token

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

Customize the agent

Adjust the role, goal, and backstory to fit your use case

Run the crew

Run python crew.py. CrewAI auto-discovers 21 tools from Lob

Why Use CrewAI with the Lob MCP Server

CrewAI Multi-Agent Orchestration Framework provides unique advantages when paired with Lob through the Model Context Protocol.

Multi-agent collaboration lets you decompose complex workflows into specialized roles, one agent researches, another analyzes, a third generates reports, each with access to MCP tools

CrewAI's native MCP integration requires zero adapter code: pass Vinkius Edge URL directly in the `mcps` parameter and agents auto-discover every available tool at runtime

Built-in task delegation and shared memory mean agents can pass context between steps without manual state management, enabling multi-hop reasoning across tool calls

Sequential and hierarchical crew patterns map naturally to real-world workflows: enumerate subdomains → analyze DNS history → check WHOIS records → compile findings into actionable reports

Lob + CrewAI Use Cases

Practical scenarios where CrewAI combined with the Lob MCP Server delivers measurable value.

Automated multi-step research: a reconnaissance agent queries Lob for raw data, then a second analyst agent cross-references findings and flags anomalies. all without human handoff

Scheduled intelligence reports: set up a crew that periodically queries Lob, analyzes trends over time, and generates executive briefings in markdown or PDF format

Multi-source enrichment pipelines: chain Lob tools with other MCP servers in the same crew, letting agents correlate data across multiple providers in a single workflow

Compliance and audit automation: a compliance agent queries Lob against predefined policy rules, generates deviation reports, and routes findings to the appropriate team

Lob MCP Tools for CrewAI (21)

These 21 tools become available when you connect Lob to CrewAI 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 CrewAI

Ready-to-use prompts you can give your CrewAI 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 CrewAI

Common issues when connecting Lob to CrewAI through the Vinkius, and how to resolve them.

MCP tools not discovered

Ensure the Edge URL is correct. CrewAI connects lazily when the crew starts. check console output.

Agent not using tools

Make the task description specific. Instead of "do something", say "Use the available tools to list contacts".

Timeout errors

CrewAI has a 10s connection timeout by default. Ensure your network can reach the Edge URL.

Rate limiting or 429 errors

Vinkius enforces per-token rate limits. Check your subscription tier and request quota in the dashboard. Upgrade if you need higher throughput.

Lob + CrewAI FAQ

Common questions about integrating Lob MCP Server with CrewAI.

How does CrewAI discover and connect to MCP tools?

CrewAI connects to MCP servers lazily. when the crew starts, each agent resolves its MCP URLs and fetches the tool catalog via the standard tools/list method. This means tools are always fresh and reflect the server's current capabilities. No tool schemas need to be hardcoded.

Can different agents in the same crew use different MCP servers?

Yes. Each agent has its own mcps list, so you can assign specific servers to specific roles. For example, a reconnaissance agent might use a domain intelligence server while an analysis agent uses a vulnerability database server.

What happens when an MCP tool call fails during a crew run?

CrewAI wraps tool failures as context for the agent. The LLM receives the error message and can decide to retry with different parameters, fall back to a different tool, or mark the task as partially complete. This resilience is critical for production workflows.

Can CrewAI agents call multiple MCP tools in parallel?

CrewAI agents execute tool calls sequentially within a single reasoning step. However, you can run multiple agents in parallel using process=Process.parallel, each calling different MCP tools concurrently. This is ideal for workflows where separate data sources need to be queried simultaneously.

Can I run CrewAI crews on a schedule (cron)?

Yes. CrewAI crews are standard Python scripts, so you can invoke them via cron, Airflow, Celery, or any task scheduler. The crew.kickoff() method runs synchronously by default, making it straightforward to integrate into existing pipelines.