Connect
Optimize
Secure
Factorial MCP Server
for AI Agents
Production-ready Factorial MCP server with 127 extensible actions — plus built-in authentication, security, and optimized execution.
Factorial MCP Server
Built by 
StackOne
StackOne 
Coverage
127 Agent Actions
Create, read, update, and delete across Factorial — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your Factorial MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every Factorial 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 Factorial call.
Tools Discovery →What is the Factorial MCP Server?
A Factorial MCP server lets AI agents read and write Factorial data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Factorial MCP server ships with 127 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 Factorial MCP Tools and Actions
Every action from Factorial's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Answers
- Create Answer
Create a new answer to an application question
- List Answers
Retrieve a list of all answers to job application questions
- Get Answer
Retrieve detailed information for a specific answer
Application Phases
- List Application Phases
Retrieve a list of all application phases in the hiring pipeline.
- Get Application Phase
Retrieve detailed information for a specific application phase
Applications
- Create Application
Create a new job application
- List Applications
Retrieve a list of all job applications
- Get Application
Retrieve detailed information for a specific application
- Update Application
Update an existing job application
- Delete Application
Delete a specific job application
Candidate Sources
- List Candidate Sources
Retrieve a list of all candidate sources.
- Get Candidate Source
Retrieve detailed information for a specific candidate source
Candidates
- Create Candidate
Create a new candidate in the ATS
- List Candidates
Retrieve a list of all candidates.
- Get Candidate
Retrieve detailed information for a specific candidate
- Update Candidate
Update an existing candidate
- Delete Candidate
Delete a specific candidate
Hiring Stages
- List Hiring Stages
Retrieve a list of all hiring stages
- Get Hiring Stage
Retrieve detailed information for a specific hiring stage
Job Postings
- Create Job Posting
Create a new job posting
- List Job Postings
Retrieve a list of all job postings
- Get Job Posting
Retrieve detailed information for a specific job posting
- Update Job Posting
Update an existing job posting
- Delete Job Posting
Delete a specific job posting
Questions
- Create Question
Create a new question for a job posting
- List Questions
Retrieve a list of all questions.
- Get Question
Retrieve detailed information for a specific question
- Update Question
Update an existing question
- Delete Question
Delete a specific question
Rejection Reasons
- List Rejection Reasons
Retrieve a list of all rejection reasons.
- Get Rejection Reason
Retrieve detailed information for a specific rejection reason
Legal Entitys
- Create Legal Entity
Create a new legal entity
- Get Legal Entity
Retrieve a single legal entity by ID
Compensation Concepts
- List Compensation Concepts
Retrieve a list of all compensation concepts
- Get Compensation Concept
Retrieve a single compensation concept by ID
Custom Fields
- Create Custom Field
Create a new custom field definition
- List Custom Fields
Retrieve a list of all custom fields with filtering options
- Get Custom Field
Retrieve detailed information for a specific custom field
- Delete Custom Field
Delete a custom field definition
Custom Field Options
- Create Custom Field Option
Create a new option for a custom field
- List Custom Field Options
Retrieve all options for custom fields
- Get Custom Field Option
Retrieve a specific custom field option by ID
Resource Fields
- Create Resource Field
Create a new resource field for a schema
- List Resource Fields
Retrieve all resource fields for custom schemas
- Get Resource Field
Retrieve a specific resource field by ID
Custom Field Values
- Create Custom Field Value
Create a new custom field value
- List Custom Field Values
Retrieve all custom field values
- Get Custom Field Value
Retrieve a specific custom field value by ID
- Update Custom Field Value
Update an existing custom field value
Custom Resources
- List Custom Resources
Retrieve all custom resources
- Get Custom Resource
Retrieve a specific custom resource by ID
Custom Resource Schemas
- Create Custom Resource Schema
Create a new custom resource schema
- List Custom Resource Schemas
Retrieve all custom resource schemas
- Get Custom Resource Schema
Retrieve a specific custom resource schema by ID
Custom Resource Values
- Create Custom Resource Value
Create a new custom resource value
- List Custom Resource Values
Retrieve all custom resource values
- Get Custom Resource Value
Retrieve a specific custom resource value by ID
Employee Update Absences
- List Employee Update Absences
Retrieve all absence employee updates
- Get Employee Update Absence
Retrieve a specific absence employee update by ID
Employee Update Contract Changes
- List Employee Update Contract Changes
Retrieve all contract change employee updates
- Get Employee Update Contract Change
Retrieve a specific contract change employee update by ID
Employee Update New Hires
- List Employee Update New Hires
Retrieve all new hire employee updates
- Get Employee Update New Hire
Retrieve a specific new hire employee update by ID
Employee Update Personal Changes
- List Employee Update Personal Changes
Retrieve all personal change employee updates
- Get Employee Update Personal Change
Retrieve a specific personal change employee update by ID
Employee Update Terminations
- List Employee Update Terminations
Retrieve all termination employee updates
- Get Employee Update Termination
Retrieve a specific termination employee update by ID
Employees
- List Employees
Retrieve a list of all employees
- Get Employee
Retrieve detailed information for a specific employee
- Update Employee
Update an existing employee's information
Company Holidays
- List Company Holidays
Retrieve all company holidays
- Get Company Holiday
Retrieve a specific company holiday by ID
Locations
- Create Location
Create a new location
- List Locations
Retrieve a list of all locations
- Get Location
Retrieve detailed information for a specific location
- Update Location
Update an existing location
- Delete Location
Delete a location
Work Areas
- Create Work Area
Create a new work area
- List Work Areas
Retrieve a list of all work areas
- Get Work Area
Retrieve detailed information for a specific work area
- Update Work Area
Update an existing work area
Team Memberships
- Create Team Membership
Create a new team membership
- List Team Memberships
Retrieve a list of all team memberships
- Get Team Membership
Retrieve detailed information for a specific team membership
- Update Team Membership
Update an existing team membership
- Delete Team Membership
Delete a team membership
Teams
- Create Team
Create a new team
- List Teams
Retrieve a list of all teams
- Get Team
Retrieve detailed information for a specific team
- Update Team
Update an existing team
- Delete Team
Delete a team
Leave Types
- Create Leave Type
Create a new leave type
- List Leave Types
Retrieve all leave types
- Get Leave Type
Retrieve a specific leave type by ID
- Update Leave Type
Update an existing leave type
Leaves
- Create Leave
Create a new leave request
- List Leaves
Retrieve all leave requests
- Get Leave
Retrieve a specific leave request by ID
- Update Leave
Update an existing leave request
- Delete Leave
Delete a leave request
Timeoff Policys
- Create Timeoff Policy
Create a new timeoff policy
- Get Timeoff Policy
Retrieve a specific timeoff policy by ID
- Update Timeoff Policy
Update an existing timeoff policy
- Delete Timeoff Policy
Delete a timeoff policy
Policy Assignments
- Create Policy Assignment
Create a new policy assignment
- List Policy Assignments
Retrieve all policy assignments
- Get Policy Assignment
Retrieve a specific policy assignment by ID
- Update Policy Assignment
Update an existing policy assignment
- Delete Policy Assignment
Delete a policy assignment
Other (18)
- Create Employee With Contract
Create a new employee with contract details
- Get Credentials
Retrieve information about the current API token owner.
- List Legal Entities
Retrieve a list of all legal entities
- List Employee Update Summaries
Retrieve all employee update summaries
- Get Employee Update Summary
Retrieve a specific employee update summary by ID
- List Timeoff Policies
Retrieve all timeoff policies
- List Policy Timelines
Retrieve all policy timelines
- Set Employee Access Start Date
Set regular access start date for an employee
- Apply To Job
Submit a job application as a candidate
- Duplicate Job Posting
Duplicate an existing job posting
- Invite Employee
Send an email invitation to an unconfirmed employee
- Terminate Employee
Terminate an employee
- Unterminate Employee
Reverse the termination of an employee
- Archive Work Area
Archive a work area
- Unarchive Work Area
Unarchive a work area
- Approve Leave
Approve a leave request
- Approve All Leaves
Approve multiple leave requests
- Reject Leave
Reject a leave request
Set Up Your Factorial MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to Factorial 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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Factorial 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
Factorial MCP Server FAQ
Factorial MCP server vs direct API integration — what's the difference?
A Factorial MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Factorial. A Factorial 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 Factorial at runtime. StackOne provides both.
How does Factorial authentication work for AI agents?
Factorial 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 Factorial account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are Factorial MCP tools vulnerable to prompt injection?
Yes — Factorial 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 Factorial agent and how do I avoid it?
Context bloat happens when Factorial tool schemas and API responses eat your Factorial agent's memory, preventing it from reasoning effectively. A single Factorial 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 Factorial agent can access?
Yes — you can limit which actions your Factorial 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 Factorial MCP server?
Yes — you can create custom agent actions for your Factorial MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Factorial's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Factorial MCP server?
Skip a Factorial MCP server if your integration is purely software-to-software — direct Factorial 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 Factorial actions at runtime.
What AI frameworks and AI clients does the StackOne Factorial MCP server support?
The StackOne Factorial 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.