Bring Direct Mail
to OpenAI Agents SDK
Learn how to connect Lob to OpenAI Agents SDK and start using 9 AI agent tools in minutes. Fully managed, enterprise secure, and ready to use without writing a single line of code.
What is the Lob MCP Server?
Connect your Lob account to any AI agent and manage direct mail through natural conversation.
What you can do
- Letter Sending — Create and send letters with PDF or HTML content
- Postcard Campaigns — Send postcards with front/back designs
- Check Printing — Create and mail checks with payment details
- Address Verification — Verify and standardize US addresses
- Template Management — Browse and manage mail templates
- Delivery Tracking — Track mail pieces through the postal system
How it works
1. Subscribe to this server
2. Enter your Lob API Key (test or live)
3. Start sending mail from Claude, Cursor, or any MCP-compatible client
Who is this for?
- Marketing — run direct mail campaigns with postcards and letters
- Finance — automate check printing and mailing
- Operations — verify addresses and track mail delivery
Built-in capabilities (9)
Suggest address completions
Send a physical check
Supports certified mail and custom inserts. Send a physical letter
Supports HTML or PDF for front and back. Send a physical postcard
Track a mail piece
List sent letters
List sent postcards
Verify an international address
Verify a US address
Why OpenAI Agents SDK?
The OpenAI Agents SDK auto-discovers all 9 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 Vinkius.
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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
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Lightweight and composable: chain multiple agents and MCP servers in a single pipeline with minimal boilerplate
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First-party OpenAI support ensures optimal compatibility with GPT models for tool calling and structured output
Lob in OpenAI Agents SDK
Lob and 3,400+ other MCP servers. One platform. One governance layer.
Teams that connect Lob to OpenAI Agents SDK through Vinkius don't need to source, host, or maintain individual MCP servers. Every tool call runs inside a hardened runtime with credential isolation, DLP, and a signed audit chain.
Raw MCP | Vinkius | |
|---|---|---|
| Server catalog | Find and host yourself | 3,400+ managed |
| Infrastructure | Self-hosted | Sandboxed V8 isolates |
| Credential handling | Plaintext in config | Vault + runtime injection |
| Data loss prevention | None | Configurable DLP policies |
| Kill switch | None | Global instant shutdown |
| Financial circuit breakers | None | Per-server limits + alerts |
| Audit trail | None | Ed25519 signed logs |
| SIEM log streaming | None | Splunk, Datadog, Webhook |
| Honeytokens | None | Canary alerts on leak |
| Custom domains | Not applicable | DNS challenge verified |
| GDPR compliance | Manual effort | Automated purge + export |
Why teams choose Vinkius for Lob in OpenAI Agents SDK
The Lob 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. All 9 tools execute in hardened sandboxes optimized for native MCP execution.
Your AI agents in OpenAI Agents SDK only access the data you authorize, with DLP that blocks sensitive information from ever reaching the model, kill switch for instant shutdown, and up to 60% token savings. Enterprise-grade infrastructure, zero maintenance.
* 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
How Vinkius secures
Lob for OpenAI Agents SDK
Every tool call from OpenAI Agents SDK to the Lob MCP Server is protected by DLP redaction, cryptographic audit chains, V8 sandbox isolation, kill switch, and financial circuit breakers.
Frequently asked questions
Can I send letters and postcards through the AI agent?
Yes. Create and send letters with PDF/HTML content and postcards with custom designs. Track delivery through the postal system.
Does Lob use Basic Auth?
Yes. Lob uses HTTP Basic Auth with the API Key as username (no password) against api.lob.com/v1.
Can I verify US addresses?
Yes. Verify and standardize US addresses with CASS certification. Returns deliverability status, corrected addresses, and coordinates.
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.
Can I use multiple MCP servers in one agent?
Yes. Pass a list of MCPServerSse instances to the agent constructor. The agent can use tools from all connected servers within a single run.
Does the SDK support streaming responses?
Yes. The SDK supports SSE and Streamable HTTP transports, both of which work natively with Vinkius.
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.