Connect
Optimize
Secure
Live 81 Actions
Close MCP Server
for AI Agents
Connect your AI agent to StackOne's Close MCP server and give it 81 MCP tools out of the box. Auth, tool execution, and security all managed.
Close MCP Server
Built by 
StackOne
StackOne 
Coverage
81 Agent Actions
Create, read, update, and delete across Close — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Close MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Close 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 Close call.
Tools Discovery →What is the Close MCP Server?
A Close MCP server lets AI agents read and write Close data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Close MCP server ships with 81 pre-built actions, fully extensible via the Connector Builder — plus managed authentication, prompt injection defense, observability, and agent execution runtime. Connect it from MCP clients like Claude Desktop, Claude Code, Cursor, Goose, and VS Code, or from agent frameworks like OpenAI Agents SDK, LangChain, and Vercel AI SDK.
All Close MCP Tools
Every action from Close's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Notes
- Create Note
Create a note activity on a lead
- List Notes
List or filter all note activities
- Get Note
Get a single note activity by ID
- Update Note
Update a note activity
- Delete Note
Delete a note activity
Calls
- List Calls
List or filter all call activities
- Get Call
Get a single call activity by ID
Emails
- List Emails
List or filter all email activities
- Get Email
Get a single email activity by ID
Meetings
- List Meetings
List or filter all meeting activities
- Get Meeting
Get a single meeting activity by ID
Contacts
- Create Contact
Create a new contact on a lead
- List Contacts
List all contacts in your Close organization
- Get Contact
Retrieve a single contact by ID
- Update Contact
Update an existing contact
- Delete Contact
Delete a contact by ID
Lead Custom Fields
- Create Lead Custom Field
Create a new custom field for leads
- List Lead Custom Fields
List all custom fields defined for leads
- Get Lead Custom Field
Retrieve a single lead custom field by ID
- Update Lead Custom Field
Update a lead custom field
- Delete Lead Custom Field
Delete a lead custom field
Contact Custom Fields
- List Contact Custom Fields
List all custom fields defined for contacts
- Get Contact Custom Field
Retrieve a single contact custom field by ID
Opportunity Custom Fields
- List Opportunity Custom Fields
List all custom fields defined for opportunities
- Get Opportunity Custom Field
Retrieve a single opportunity custom field by ID
Groups
- Create Group
Create a new group
- List Groups
List all groups in your organization
- Get Group
Retrieve a single group by ID
- Update Group
Update an existing group
- Delete Group
Delete a group
Leads
- Create Lead
Create a new lead
- List Leads
List all leads in your Close organization
- Get Lead
Retrieve a single lead by ID
- Update Lead
Update an existing lead
- Delete Lead
Delete a lead by ID
Opportunitys
- Create Opportunity
Create a new opportunity on a lead
- Get Opportunity
Retrieve a single opportunity by ID
- Update Opportunity
Update an existing opportunity
- Delete Opportunity
Delete an opportunity by ID
Pipelines
- Create Pipeline
Create a new pipeline
- List Pipelines
List all pipelines in your organization
- Update Pipeline
Update an existing pipeline
- Delete Pipeline
Delete a pipeline
Roles
- Create Role
Create a new role
- List Roles
List all roles in your organization
- Get Role
Retrieve a single role by ID
- Update Role
Update an existing role
- Delete Role
Delete a role
Sequences
- List Sequences
List all sequences (workflows)
- Get Sequence
Retrieve a single sequence by ID
Sequence Subscriptions
- List Sequence Subscriptions
List subscriptions for a sequence
- Get Sequence Subscription
Retrieve a single sequence subscription by ID
- Update Sequence Subscription
Update a sequence subscription (pause/resume)
Smart Views
- Create Smart View
Create a new smart view
- List Smart Views
List all smart views in your organization
- Get Smart View
Retrieve a single smart view by ID
- Update Smart View
Update an existing smart view
- Delete Smart View
Delete a smart view
Lead Status
- Create Lead Status
Create a new lead status
- Update Lead Status
Rename a lead status
- Delete Lead Status
Delete a lead status
Opportunity Status
- Create Opportunity Status
Create a new opportunity status
- Update Opportunity Status
Rename an opportunity status
- Delete Opportunity Status
Delete an opportunity status
Tasks
- Create Task
Create a new task on a lead
- List Tasks
List or filter tasks
- Get Task
Retrieve a single task by ID
- Update Task
Update an existing task
- Delete Task
Delete a task by ID
Users
- List Users
List all users in your organization
- Get User
Retrieve a single user by ID
Other (10)
- List Activities
List or filter all activity types
- List SMS
List or filter all SMS activities
- List Opportunities
List or filter opportunities
- List Lead Statuses
List all lead statuses in your organization
- List Opportunity Statuses
List all opportunity statuses in your organization
- Get Current User
Fetch information about the authenticated user
- List User Availabilities
List user availability statuses
- Log Call
Log an external call activity on a lead
- Merge Leads
Merge two leads into one
- Subscribe Contact To Sequence
Subscribe a contact to a sequence
Close AI Agent Use Cases
Connect your AI agent to Close and help your team scale the sales operations they run by hand today.
Post-Demo Follow-Up
Use StackOne to connect your AI agent to your CRM, email, and calendar tools to automate post-demo follow-up.
View Deal Risk Scoring
Use StackOne to connect your AI agent to your CRM, email, and calendar tools to automate deal risk scoring and pipeline alerts.
View Outbound Prospecting
Use StackOne to connect your AI agent to your CRM, sales engagement, and messaging tools to automate outbound prospecting.
ViewSet Up Your Close MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Close in under 10 lines of code.
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>"
]
}
}
}Check More CRM MCP Servers
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Platform 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
Close MCP Server FAQ
Does StackOne have a Close MCP server?
Yes. StackOne offers a hosted Close MCP server with 81 pre-built actions, and every action is tested and QA'd by StackOne. Connect it to Claude, Cursor, and any other MCP client, or to any agent framework through the AI Action SDK. It ships with managed agent authentication, prompt injection defense, and tool discovery with server-side execution that preserve your agent's context window and keep reasoning performance.
Close MCP server vs direct API integration — what's the difference?
A Close MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Close. A Close 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 Close at runtime. StackOne provides both.
How does Close authentication work for AI agents?
Close 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 Close account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Close MCP tools vulnerable to prompt injection?
Yes — Close 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 Close agent and how do I avoid it?
Context bloat happens when Close tool schemas and API responses eat your Close agent's memory, preventing it from reasoning effectively. A single Close 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 Close agent can access?
Yes — you can limit which actions your Close 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 Close MCP server?
Yes — you can create custom agent actions for your Close MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Close's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Close MCP server?
Skip a Close MCP server if your integration is purely software-to-software — direct Close 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 Close actions at runtime.
What AI frameworks and AI clients does the StackOne Close MCP server support?
The StackOne Close 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.