Lemlist MCP Server
for AI Agents

Q: What AI frameworks and AI clients does the StackOne Lemlist MCP server support?

The StackOne Lemlist MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

Production-ready Lemlist MCP server with 60 extensible actions — plus built-in authentication, security, and optimized execution.

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Lemlist MCP Server

Built by

StackOne

Coverage

60 Agent Actions

Create, read, update, and delete across Lemlist — and extend your agent's capabilities with custom actions.

MCP Actions → Create Actions →

Authentication

Agent Tool Authentication

Per-user OAuth in one call. Your Lemlist MCP server gets session-scoped tokens with zero credentials stored on your infra.

Agent Auth →

Security

Agent Protection

Every Lemlist tool response scanned for prompt injection in milliseconds — 88.7% accuracy, all running on CPU.

Prompt Injection Defense →

Performance

Max Agent Context. Min Cost.

Free up to 96% of your agent's context window to enhance reasoning and reduce cost, on every Lemlist call.

Tools Discovery →

What is the Lemlist MCP Server?

A Lemlist MCP server lets AI agents read and write Lemlist data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Lemlist MCP server ships with 60 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, and optimized agent context. Connect it from MCP clients like Claude Desktop, Cursor, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.

All Lemlist MCP Tools and Actions

Every action from Lemlist's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.

Campaigns

Create Campaign
Create a new campaign with an auto-generated sequence and schedule.
List Campaigns
Retrieve a paginated list of all campaigns in your team.
Get Campaign
Retrieve detailed information about a specific campaign by ID.
Update Campaign
Update the settings and configuration of an existing campaign.

Campaign Leads

Export Campaign Leads
Export leads from a campaign with flexible filtering and format options.
Get Campaign Leads
Retrieve leads from a specific campaign, optionally filtered by state.

Contacts

List Contacts
Retrieve multiple contacts by their IDs or email addresses.
Get Contact
Retrieve a single contact by ID or email address.

Lead In Campaigns

Create Lead In Campaign
Create a new lead and add it to a specific campaign.
Update Lead In Campaign
Update an existing lead's information in a specific campaign.

Schedules

Create Schedule
Create a new sending schedule to control campaign delivery timing.
List Schedules
Retrieve a paginated list of all sending schedules.
Get Schedule
Retrieve details of a specific sending schedule by ID.
Update Schedule
Update the configuration of an existing sending schedule.
Delete Schedule
Permanently delete a sending schedule.

Sequence Steps

Update Sequence Step
Update the content or configuration of an existing sequence step.
Delete Sequence Step
Remove a step from a campaign sequence.

Tasks

Create Task
Create a new task and assign it to a team member.
List Tasks
Retrieve a paginated list of tasks across your team.
Update Task
Update an existing task's details, assignee, or completion status.

Unsubscribes

List Unsubscribes
Retrieve a paginated list of all unsubscribed email addresses.
Export Unsubscribes
Export all unsubscribed emails and domains as a CSV file.

Webhooks

Add Webhook
Register a new webhook to receive lemlist event notifications.
List Webhooks
Retrieve all webhooks configured for your lemlist team.
Delete Webhook
Remove a webhook from your lemlist team.

Other (35)

Import Leads From CRM
Import leads into a campaign directly from a connected CRM using a saved filter.
Add Step To Sequence
Add a new step to an existing campaign sequence.
Add Email To Unsubscribe List
Add an email address to the team unsubscribe list.
List Activities
Retrieve a paginated list of activities across all campaigns.
Get Campaign Stats
Retrieve performance statistics for a specific campaign.
Get Campaign Reports
Retrieve aggregated reports and statistics for one or multiple campaigns.
Get Campaign Export Status
Check the status of a running campaign export job and retrieve the download URL when complete.
Get Enrichment Result
Retrieve the result of a completed enrichment job.
Get Lead By Email
Retrieve a lead by their email address across all campaigns.
Get Lead By ID Or Email
Retrieve a lead by their ID or email address.
Get Campaign Schedules
Retrieve all schedules associated with a specific campaign.
Get Campaign Sequences
Retrieve the sequences and steps configured for a specific campaign.
Get Team
Retrieve information about your lemlist team.
Get Team Credits
Retrieve the remaining credits balance for your lemlist team.
Get Team Senders
Retrieve the list of senders and their associated campaigns.
Get Unsubscribe By Email
Retrieve the unsubscribe record for a specific email address.
Get User
Retrieve details of a specific team member by user ID.
Set Export Email Notification
Configure an email address to be notified when a campaign export is complete.
Delete Lead From Campaign
Remove a lead from a specific campaign, deleting all associated information and statistics.
Remove Email From Unsubscribe List
Remove an email address from the unsubscribe list to allow future outreach.
Start Campaign
Start or resume a paused campaign.
Pause Campaign
Pause a running campaign without affecting scheduled leads.
Start Campaign Export
Initiate an asynchronous CSV export of campaign statistics.
Enrich Lead
Trigger enrichment for an existing lead to find email, phone, or LinkedIn data.
Enrich Data
Enrich a contact by email or LinkedIn URL without requiring an existing lead.
Bulk Enrich Data
Trigger enrichment for multiple contacts in a single request.
Pause Lead
Pause a lead's activity in all campaigns or a specific campaign.
Resume Paused Lead
Resume a previously paused lead in all campaigns or a specific campaign.
Mark Lead As Interested
Mark a lead as interested across all campaigns.
Mark Lead As Not Interested
Mark a lead as not interested across all campaigns.
Mark Lead As Interested In Campaign
Mark a lead as interested within a specific campaign.
Mark Lead As Not Interested In Campaign
Mark a lead as not interested within a specific campaign.
Unsubscribe Lead From Campaign
Unsubscribe a lead from a specific campaign by email address.
Associate Schedule With Campaign
Link an existing schedule to a campaign to control its sending times.
Ignore Tasks
Mark one or more tasks as ignored.

Set Up Your Lemlist MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Lemlist in under 10 lines of code.

MCP Clients

Agent Frameworks

Claude Desktop-

JSON

Docs

{
  "mcpServers": {
    "stackone": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote@latest",
        "https://api.stackone.com/mcp?x-account-id=<account_id>",
        "--header",
        "Authorization: Basic <YOUR_BASE64_TOKEN>"
      ]
    }
  }
}

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Lemlist MCP Server Resources

MCP Code Mode: Keeping Tool Responses Out of Agent Context

Anthropic's code_execution processes data already in context. Custom MCP code mode keeps raw tool responses in a sandbox. 14K tokens vs 500.

11 min

Comparing BM25, TF-IDF, and Hybrid Search for MCP Tool Discovery

Benchmarking BM25, TF-IDF, and hybrid search for MCP tool discovery across 916 tools. The 80/20 TF-IDF/BM25 hybrid hits 21% Top-1 accuracy in under 1ms.

10 min

Indirect Prompt Injection Defense for MCP Tools: A Technical Guide

MCP tools that read emails, CRM records, and tickets are indirect prompt injection vectors. Here's how we built a two-tier defense that scans tool results in ~11ms.

12 min

Lemlist MCP Server FAQ

Lemlist MCP server vs direct API integration — what's the difference?

A Lemlist MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Lemlist. A Lemlist MCP server is for AI agents — MCP clients like Claude and Cursor, plus framework agents built with OpenAI, LangChain, or Vercel AI — discovering and calling Lemlist at runtime. StackOne provides both.

How does Lemlist authentication work for AI agents?

Lemlist authentication for AI agents works through a StackOne Connect Session. Create one via the dashboard or the SDK — you get an auth link and ready-to-paste config for Claude Desktop, Cursor, and other MCP clients. Your user authenticates their own Lemlist account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.

Are Lemlist MCP tools vulnerable to prompt injection?

Yes — Lemlist MCP tools can be vulnerable to indirect prompt injection. Any tool that reads user-written content — documents, messages, tickets, records, or free-text fields — is a potential vector. StackOne Defender scans every tool response before it enters the agent's context — regex patterns in ~1ms, then a MiniLM classifier in ~4ms. 88.7% accuracy, CPU-only.

What is the context bloat of a Lemlist agent and how do I avoid it?

Context bloat happens when Lemlist tool schemas and API responses eat your Lemlist agent's memory, preventing it from reasoning effectively. A single Lemlist query can return a massive JSON response, and connecting multiple tools compounds the problem. Tools Discovery and Code Mode reduce context bloat — loading only relevant tools per query and keeping raw responses out of the agent's context.

Can I limit which actions my Lemlist agent can access?

Yes — you can limit which actions your Lemlist agent can access directly from the StackOne dashboard. Toggle actions on or off, or restrict them to specific accounts, with no code changes to your agent. Session tokens can be scoped to exact actions so if one leaks, exposure stays contained.

Can I create custom agent actions for my Lemlist MCP server?

Yes — you can create custom agent actions for your Lemlist MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Lemlist's API, generate production-ready connector YAML, test against the live API, and validate before you ship.

When should I NOT use a Lemlist MCP server?

Skip a Lemlist MCP server if your integration is purely software-to-software — direct Lemlist API integration is simpler when no AI agent is involved. For deterministic, compliance-critical operations (financial transactions, regulatory reporting), direct API gives you predictable behavior without agent-driven decision-making. MCP shines when AI agents need to dynamically discover and call Lemlist actions at runtime.

What AI frameworks and AI clients does the StackOne Lemlist MCP server support?

The StackOne Lemlist MCP server supports both. MCP clients (paste-and-go apps): Claude Desktop, Claude Code, Cursor, VS Code, Goose. Agent frameworks (code SDKs you build with): OpenAI Agents SDK, Anthropic, Vercel AI, Google ADK, CrewAI, Pydantic AI, LangChain, LangGraph, Azure AI Foundry.

Put your AI agents to work

All the tools you need to build and scale AI agent integrations, with best-in-class connectivity, execution, and security.

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Lemlist MCP Serverfor AI Agents