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Closing the Loop: A Self-Evolving Defense
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Connect to everything your agents need, without writing the infrastructure to get there.

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Zelt MCP Server
for AI Agents

Connect your AI agent to StackOne's Zelt MCP server and give it 34 MCP tools out of the box. Auth, tool execution, and security all managed.

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Zelt MCP Server
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Coverage

34 Agent Actions

Create, read, update, and delete across Zelt — and extend your agent's capabilities with custom actions.

MCP Actions → Build Actions →

Authentication

Agent Tool Authentication

Per-user OAuth in one call. Your Zelt MCP server gets session-scoped tokens with zero credentials stored on your infra.

Agent Auth →

Security

Agent Protection

Every Zelt 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 Zelt call.

Tools Discovery →

What is the Zelt MCP Server?

A Zelt MCP server lets AI agents read and write Zelt data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Zelt MCP server ships with 34 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 Zelt MCP Tools

Every action from Zelt's API, ready for your agent. Create, read, update, and delete — scoped to exactly what you need.

User Compensations

  • Create User Compensation

    Create a new user compensation record

  • Update User Compensation

    Update user compensation record

  • Delete User Compensation

    Delete user compensation record

User Contract Records

  • Update User Contract Record

    Update an existing user contract record

  • Delete User Contract Record

    Delete a specific user contract record

User Role Records

  • Update User Role Record

    Update an existing user role record

  • Delete User Role Record

    Delete a specific user role record

User Basic Details

  • Get User Basic Details

    Get basic details for a specific user

  • Update User Basic Details

    Update basic details for a specific user

User Personal Infos

  • Get User Personal Info

    Get personal information for a specific user

  • Update User Personal Info

    Update personal information for a specific user

Other (23)

  • Create New User Contract

    Create a new contract record for a user

  • Create New User Role Record

    Create a new role record for a user

  • Create User

    Create a new user in the system

  • Get User Addresses By User ID

    Get all address records for a specific user

  • Get Currently Effective User Address

    Get the currently effective address for a specific user

  • List Absences

    List absences

  • List All Sites For Company

    List all sites for company

  • List All Departments For Company

    List all departments for company

  • List All Job Positions

    List all job positions

  • List All Job Levels

    List all job levels

  • List Permission Group Members

    List all permission groups in the company together with the members of each group

  • Get User Compensation Details

    Get user compensation details by compensation record ID

  • Get Currently Effective Compensation Details

    Get currently effective compensation details

  • Get User Contracts By User ID

    Get all contracts for a specific user

  • Get Current User Contract By User ID

    Get the current active contract for a specific user

  • List Document Types For Company

    Get all available document types for the company

  • Get User Events

    Get user events by user id

  • Get Currently Effective User Event

    Get currently effective user event

  • Get User Role Details

    Get all role details for a specific user

  • Get Currently Effective User Role

    Get the current active role for a specific user

  • List All Users

    Retrieve a list of all users for the company

  • Bulk Import Attendance Entries

    Bulk import attendance entries (max 100 per request)

  • Rehire User

    Rehire a user

Zelt AI Agent Use Cases

Connect your AI agent to Zelt and help your team scale the HR operations they run by hand today.

Employee Onboarding

Use StackOne to connect your AI agent to your HRIS, identity management, and LMS to automate employee onboarding.

View
WorkdayBambooHRPersonioHiBobGustoRipplingOkta360Learning
HR Policy Q&A Chatbot

Use StackOne to connect your AI agent to your HRIS, knowledge base, and messaging tools to automate HR policy Q&A.

View
WorkdayBambooHRPersonioHiBobGustoRipplingSharePointConfluence
Employee Offboarding

Use StackOne to connect your AI agent to your HRIS, identity management, and ITSM to automate employee offboarding and deprovisioning.

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WorkdayBambooHRPersonioOktaServiceNowRipplingGustoJira
More HRIS & HCM use cases

Set Up Your Zelt MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Zelt in under 10 lines of code.

MCP Clients

Claude Desktop setup guide
Claude Code setup guide
Cursor setup guide
Goose setup guide

Agent Frameworks

Claude Desktop
{
  "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 HRIS / HCM MCP Servers

UKG Ready

139+ actions

Workday (Rest and Soap)

128+ actions

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127+ actions

HiBob

123+ actions

Oracle Fusion HCM

120+ actions

Humaans

117+ actions

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111+ actions

All HRIS / HCM MCP Servers →

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

MCP vs A2A: Architecture, Security, and When to Use Each

MCP vs A2A: what each protocol standardizes, how they differ, their shared security risks including indirect prompt injection, and when to use one, both, or a hybrid architecture.

12 min

MCP vs API: What 200+ Connector Builds Taught Us

MCP wraps APIs, it doesn't replace them. After building 200+ connectors that serve both, here's when each approach wins.

14 min read

Zelt MCP Server FAQ

Does StackOne have a Zelt MCP server?
Yes. StackOne offers a hosted Zelt MCP server with 34 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.
Zelt MCP server vs direct API integration — what's the difference?
A Zelt MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Zelt. A Zelt 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 Zelt at runtime. StackOne provides both.
How does Zelt authentication work for AI agents?
Zelt 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 Zelt account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.
Are Zelt MCP tools vulnerable to prompt injection?
Yes — Zelt 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 Zelt agent and how do I avoid it?
Context bloat happens when Zelt tool schemas and API responses eat your Zelt agent's memory, preventing it from reasoning effectively. A single Zelt 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 Zelt agent can access?
Yes — you can limit which actions your Zelt 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 Zelt MCP server?
Yes — you can create custom agent actions for your Zelt MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Zelt's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Zelt MCP server?
Skip a Zelt MCP server if your integration is purely software-to-software — direct Zelt 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 Zelt actions at runtime.
What AI frameworks and AI clients does the StackOne Zelt MCP server support?
The StackOne Zelt 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.

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