Connect
Optimize
Secure
Kit MCP Server
for AI Agents
Production-ready Kit MCP server with 53 extensible actions — plus built-in authentication, security, and optimized execution.
Kit MCP Server
Built by 
StackOne
StackOne 
Coverage
53 Agent Actions
Create, read, update, and delete across Kit — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Kit MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Kit 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 Kit call.
Tools Discovery →What is the Kit MCP Server?
A Kit MCP server lets AI agents read and write Kit data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Kit MCP server ships with 53 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 Kit MCP Tools and Actions
Every action from Kit's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Account Colors
- List Account Colors
Retrieve the color settings for the current account
- Update Account Colors
Update the color settings for the current account
Broadcasts
- Create Broadcast
Draft or schedule a broadcast email to all or a subset of subscribers
- List Broadcasts
Retrieve a paginated list of all broadcasts
- Get Broadcast
Retrieve a specific broadcast by ID
- Update Broadcast
Update an existing broadcast
- Delete Broadcast
Delete a broadcast by ID
Custom Fields
- Create Custom Field
Create a new custom field for subscribers
- List Custom Fields
Retrieve all custom fields
- Update Custom Field
Update a custom field label by ID
- Delete Custom Field
Delete a custom field by ID
Purchases
- Create Purchase
Record a new purchase for a subscriber
- List Purchases
Retrieve a paginated list of all purchases
- Get Purchase
Retrieve a specific purchase by ID
Subscribers
- Create Subscriber
Create or update a subscriber (upsert)
- Get Subscriber
Retrieve a specific subscriber by ID
- List Subscribers
Retrieve a paginated list of all subscribers
- Update Subscriber
Update an existing subscriber by ID
Tags
- Create Tag
Create a new tag
- List Tags
Retrieve a paginated list of all tags
- Update Tag
Update a tag name by ID
Tag Subscribers
- List Tag Subscribers
Retrieve subscribers assigned to a specific tag
- Tag Subscriber
Add a tag to a subscriber by subscriber ID
Other (30)
- Add Subscriber To Form
Add an existing subscriber to a form by subscriber ID
- Add Subscriber To Form By Email
Add an existing subscriber to a form by email address
- Add Subscriber To Sequence
Add an existing subscriber to a sequence
- Add Subscriber To Sequence By Email
Add a subscriber to a sequence by email address
- Get Current Account
Retrieve the current Kit account and user information
- Get Creator Profile
Retrieve the creator profile for the current account
- Get Email Stats
Retrieve email performance counts for the current account
- Get Growth Stats
Retrieve subscriber growth statistics for a specific time period
- Get Broadcast Stats
Retrieve performance statistics for a specific broadcast
- List Broadcasts Stats
Retrieve statistics for multiple broadcasts
- Get Broadcast Link Clicks
Retrieve link click data for a specific broadcast
- List Email Templates
Retrieve all available email templates
- List Forms
Retrieve a paginated list of all forms
- List Form Subscribers
Retrieve subscribers who signed up through a specific form
- List Segments
Retrieve a paginated list of all segments
- List Sequences
Retrieve a paginated list of all sequences
- List Sequence Subscribers
Retrieve subscribers enrolled in a specific sequence
- Get Subscriber Stats
Retrieve email statistics for a specific subscriber
- List Subscriber Tags
Retrieve all tags assigned to a specific subscriber
- Remove Tag From Subscriber
Remove a tag from a subscriber by subscriber ID
- Remove Tag From Subscriber By Email
Remove a tag from a subscriber by email address
- Bulk Create Custom Fields
Create multiple custom fields in a single request
- Bulk Add Subscribers To Forms
Add multiple subscribers to forms in a single request
- Bulk Create Subscribers
Create multiple subscribers in a single request
- Unsubscribe Subscriber
Unsubscribe a subscriber by ID
- Filter Subscribers By Engagement
Filter subscribers based on email engagement metrics
- Bulk Create Tags
Create multiple tags in a single request
- Tag Subscriber By Email
Add a tag to a subscriber by email address
- Bulk Tag Subscribers
Apply tags to multiple subscribers in a single request
- Bulk Remove Tags From Subscribers
Remove tags from multiple subscribers in a single request
Set Up Your Kit MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Kit in under 10 lines of code.
MCP Clients
Agent Frameworks
JSON{
"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>"
]
}
}
}Kit 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
Kit MCP Server FAQ
Kit MCP server vs direct API integration — what's the difference?
A Kit MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Kit. A Kit 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 Kit at runtime. StackOne provides both.
How does Kit authentication work for AI agents?
Kit 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 Kit account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Kit MCP tools vulnerable to prompt injection?
Yes — Kit 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 Kit agent and how do I avoid it?
Context bloat happens when Kit tool schemas and API responses eat your Kit agent's memory, preventing it from reasoning effectively. A single Kit 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 Kit agent can access?
Yes — you can limit which actions your Kit 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 Kit MCP server?
Yes — you can create custom agent actions for your Kit MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Kit's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Kit MCP server?
Skip a Kit MCP server if your integration is purely software-to-software — direct Kit 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 Kit actions at runtime.
What AI frameworks and AI clients does the StackOne Kit MCP server support?
The StackOne Kit 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.