Connect
Optimize
Secure
Live 23 Actions
JOIN MCP Server
for AI Agents
Connect your AI agent to StackOne's JOIN MCP server and give it 23 MCP tools out of the box. Auth, tool execution, and security all managed.
JOIN MCP Server
Built by 
StackOne
StackOne 
Coverage
23 Agent Actions
Create, read, update, and delete across JOIN — and extend your agent's capabilities with custom actions.
Authentication
Agent Tool Authentication
Per-user OAuth in one call. Your JOIN MCP server gets session-scoped tokens with zero credentials stored on your infra.
Agent Auth →
Security
Agent Protection
Every JOIN 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 JOIN call.
Tools Discovery →What is the JOIN MCP Server?
A JOIN MCP server lets AI agents read and write JOIN data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's JOIN MCP server ships with 23 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 JOIN MCP Tools
Every action from JOIN's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.
Jobs
- Create Job
Create a new job
- List Jobs
Retrieve a list of jobs
- Get Job
Retrieve a specific job by ID
- Update Job
Update an existing job
Change Job Status
- Change Job Status
Change the status of a job
Applications
- Create Application
Create a new application
- List Applications
Retrieve a list of applications
- Get Application
Retrieve a specific application by ID
- Delete Application
Delete an application
Application Integration Datas
- Update Application Integration Data
Update the integration external ID for an application
Application Scorecards
- List Application Scorecards
Retrieve scorecards for an application
Candidates
- Update Candidate
Update a candidate's tags
Candidate Notes
- Create Candidate Note
Create a note for a candidate
- List Candidate Notes
Retrieve notes for a candidate
- Update Candidate Note
Update a candidate note
- Delete Candidate Note
Delete a candidate note
Offices
- Create Office
Create a new office
- List Offices
Retrieve a list of offices
- Get Office
Retrieve a specific office by ID
- Update Office
Update an existing office
Categories
- List Categories
Retrieve a list of job categories
Employment Types
- List Employment Types
Retrieve a list of employment types
Seniority Levels
- List Seniority Levels
Retrieve a list of seniority levels
JOIN AI Agent Use Cases
Connect your AI agent to JOIN and help your team scale the recruiting operations they run by hand today.
Job Posting Distribution
Use StackOne to connect your AI agent to your ATS and job boards to automate job posting distribution.
View Reference Check Automation
Use StackOne to connect your AI agent to your ATS, survey tools, and messaging systems to automate reference checks.
View Offer Letter Generation
Use StackOne to connect your AI agent to your ATS, HRIS, and document management tools to automate offer letter generation.
ViewSet Up Your JOIN MCP Server in Minutes
One endpoint. Any framework. Your agent is talking to JOIN 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 Recruiting 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
JOIN MCP Server FAQ
Does StackOne have a JOIN MCP server?
Yes. StackOne offers a hosted JOIN MCP server with 23 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.
JOIN MCP server vs direct API integration — what's the difference?
A JOIN MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling JOIN. A JOIN 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 JOIN at runtime. StackOne provides both.
How does JOIN authentication work for AI agents?
JOIN 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 JOIN account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via
origin_owner_id.Are JOIN MCP tools vulnerable to prompt injection?
Yes — JOIN 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 JOIN agent and how do I avoid it?
Context bloat happens when JOIN tool schemas and API responses eat your JOIN agent's memory, preventing it from reasoning effectively. A single JOIN 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 JOIN agent can access?
Yes — you can limit which actions your JOIN 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 JOIN MCP server?
Yes — you can create custom agent actions for your JOIN MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research JOIN's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a JOIN MCP server?
Skip a JOIN MCP server if your integration is purely software-to-software — direct JOIN 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 JOIN actions at runtime.
What AI frameworks and AI clients does the StackOne JOIN MCP server support?
The StackOne JOIN 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.