Connect
Optimize
Secure
Simployer One MCP Server
for AI Agents
Production-ready Simployer One MCP server with 54 extensible actions — plus built-in authentication, security, and optimized execution.
Simployer One MCP Server
Built by 
StackOne
StackOne 
Coverage
54 Agent Actions
Create, read, update, and delete across Simployer One — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Simployer One MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Simployer One 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 Simployer One call.
Tools Discovery →What is the Simployer One MCP Server?
A Simployer One MCP server lets AI agents read and write Simployer One data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Simployer One MCP server ships with 54 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 Simployer One MCP Tools and Actions
Every action from Simployer One's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Companies
- List Companies
Retrieve a list of all companies in the Simployer account
Companys
- Get Company
Retrieve a specific company by its ID
Compensations
- Create Compensation
Create a new compensation record
- List Compensations
Retrieve a list of all compensations
- Get Compensation
Retrieve a specific compensation by its ID
- Update Compensation
Update an existing compensation record
- Delete Compensation
Delete a compensation record by its ID
Cost Centers
- Create Cost Center
Create a new cost center
- List Cost Centers
Retrieve a list of all cost centers
- Get Cost Center
Retrieve a specific cost center by its ID
- Update Cost Center
Update an existing cost center
- Delete Cost Center
Delete a cost center by its ID
Departments
- Create Department
Create a new department
- List Departments
Retrieve a list of all departments
- Get Department
Retrieve a specific department by its ID
- Update Department
Update an existing department
- Delete Department
Delete a department by its ID
Employees
- Create Employee
Create a new employee
- List Employees
Retrieve a list of all employees
- Get Employee
Retrieve a specific employee by their ID
- Update Employee
Update an existing employee
- Delete Employee
Delete an employee by their ID
Employment Types
- Create Employment Type
Create a new employment type
- List Employment Types
Retrieve a list of all employment types
- Get Employment Type
Retrieve a specific employment type by its ID
- Update Employment Type
Update an existing employment type
- Delete Employment Type
Delete an employment type by its ID
Employments
- Create Employment
Create a new employment record
- List Employments
Retrieve a list of all employments
- Get Employment
Retrieve a specific employment by its ID
- Update Employment
Update an existing employment record
- Delete Employment
Delete an employment record by its ID
Leave Types
- Create Leave Type
Create a new leave type
- List Leave Types
Retrieve a list of all leave types
- Get Leave Type
Retrieve a specific leave type by its ID
- Update Leave Type
Update an existing leave type
- Delete Leave Type
Delete a leave type by its ID
Leaves
- Create Leave
Create a new leave request
- List Leaves
Retrieve a list of all leaves
- Get Leave
Retrieve a specific leave by its ID
- Update Leave
Update an existing leave request
- Delete Leave
Delete a leave request by its ID
Offices
- List Offices
Retrieve a list of all offices
- Get Office
Retrieve a specific office by its ID
Projects
- Create Project
Create a new project
- List Projects
Retrieve a list of all projects
- Get Project
Retrieve a specific project by its ID
- Update Project
Update an existing project
- Delete Project
Delete a project by its ID
Teams
- Create Team
Create a new team
- List Teams
Retrieve a list of all teams
- Get Team
Retrieve a specific team by its ID
- Update Team
Update an existing team
- Delete Team
Delete a team by its ID
Set Up Your Simployer One MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Simployer One 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>"
]
}
}
}More HRIS / HCM MCP Servers
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Simployer One 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
Simployer One MCP Server FAQ
Simployer One MCP server vs direct API integration — what's the difference?
A Simployer One MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Simployer One. A Simployer One 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 Simployer One at runtime. StackOne provides both.
How does Simployer One authentication work for AI agents?
Simployer One 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 Simployer One account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Simployer One MCP tools vulnerable to prompt injection?
Yes — Simployer One 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 Simployer One agent and how do I avoid it?
Context bloat happens when Simployer One tool schemas and API responses eat your Simployer One agent's memory, preventing it from reasoning effectively. A single Simployer One 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 Simployer One agent can access?
Yes — you can limit which actions your Simployer One 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 Simployer One MCP server?
Yes — you can create custom agent actions for your Simployer One MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Simployer One's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Simployer One MCP server?
Skip a Simployer One MCP server if your integration is purely software-to-software — direct Simployer One 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 Simployer One actions at runtime.
What AI frameworks and AI clients does the StackOne Simployer One MCP server support?
The StackOne Simployer One 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.