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Oyster HR MCP Server
for AI Agents

Connect your AI agent to StackOne's Oyster HR MCP server and give it 104 MCP tools out of the box. Auth, tool execution, and security all managed.

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Oyster HR MCP Server
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Coverage

104 Agent Actions

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

MCP Actions → Build Actions →

Authentication

Agent Tool Authentication

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

Agent Auth →

Security

Agent Protection

Every Oyster HR 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 Oyster HR call.

Tools Discovery →

What is the Oyster HR MCP Server?

A Oyster HR MCP server lets AI agents read and write Oyster HR data through the Model Context Protocol — Anthropic's open standard for connecting LLMs to external tools. StackOne's Oyster HR MCP server ships with 104 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 Oyster HR MCP Tools

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

Webhooks

  • List Webhooks

    Retrieve all webhook endpoints registered for the authenticated organization

  • Delete Webhook

    Delete a webhook endpoint by ID

Engagements

  • List Engagements

    Retrieve a paginated list of engagements (employees and contractors)

  • Get Engagement

    Retrieve details of a specific engagement by ID

Contract Changes

  • Create Contract Change

    Create a new contract change request for an engagement

  • List Contract Changes

    Retrieve all contract change requests across engagements

  • Get Contract Change

    Retrieve details for a specific contract change request

Time Off Entitlements

  • List Time Off Entitlements

    Retrieve a paginated list of time off entitlements

  • Get Time Off Entitlement

    Retrieve entitlements for an individual engagement

Time Off Requests

  • Create Time Off Request

    Create a new time off request for an engagement

  • List Time Off Requests

    Retrieve a paginated list of time off requests

  • Get Time Off Request

    Retrieve an individual time off request by ID

Expenses

  • Create Expense

    Create a new expense record

  • List Expenses

    Retrieve all expenses

  • Get Expense

    Retrieve an individual expense by ID

  • Delete Expense

    Delete an expense record by ID

Payroll Changes

  • Create Payroll Change

    Create a payroll change for an engagement

  • List Payroll Changes

    Retrieve all payroll changes

  • Get Payroll Change

    Retrieve a single payroll change by ID

  • Update Payroll Change

    Update an existing payroll change

Bank Accounts

  • List Bank Accounts

    Retrieve bank accounts for the company

  • Get Bank Account

    Retrieve bank account details by ID

Time Sheets

  • Create Time Sheet

    Create a new time sheet for an engagement

  • List Time Sheets

    Retrieve all time sheets for the company

  • Get Time Sheet

    Retrieve an individual time sheet by ID

  • Delete Time Sheet

    Delete a time sheet

Time Sheet Entrys

  • Create Time Sheet Entry

    Create a new entry in a time sheet

  • Update Time Sheet Entry

    Update an existing time sheet entry

  • Delete Time Sheet Entry

    Delete a time sheet entry

Hiring Employments

  • Create Hiring Employment

    Create a new hiring employment record

  • Get Hiring Employment

    Retrieve an individual hiring employment by ID

  • Update Hiring Employment

    Update a draft hiring employment record

  • Delete Hiring Employment

    Delete a draft hiring employment record

Other (71)

  • Get Company

    Retrieve company details for the authenticated organization

  • List Webhook Dispatches

    Retrieve all webhook dispatches for the authenticated Developer application

  • List Departments

    Retrieve a paginated list of departments

  • List Engagement Allowances

    Retrieve a paginated list of allowances for a specific engagement

  • List Engagement Bonuses

    Retrieve a paginated list of bonuses for a specific engagement

  • List Engagement Documents

    Retrieve a paginated list of documents for a specific engagement

  • List Engagement Payslips

    Retrieve a paginated list of payslips for a specific engagement

  • List Payroll

    Retrieve a paginated list of payroll entries

  • Get Payroll Item

    Retrieve a single payroll entry by ID

  • List Payroll Records

    Retrieve payroll records for an individual payroll

  • Get Default Payroll Changes Source Types

    Retrieve default payroll changes rulesets for source types

  • Get Default Payroll Changes Ruleset

    Retrieve default payroll changes ruleset

  • Get Payroll Changes Source Types

    Retrieve payroll changes rulesets for source types

  • Get Payroll Changes Ruleset

    Retrieve payroll changes ruleset

  • Get Hiring Employment Tasks

    Retrieve hiring process tasks for an employment

  • Update Personal Details

    Update personal details for an employment

  • Cancel Contract Change

    Cancel a contract change request

  • Approve Time Off Request

    Approve a pending time off request

  • Reject Time Off Request

    Reject a pending time off request

  • Approve Expense

    Approve a pending expense

  • Decline Expense

    Decline a pending expense

  • Cancel Payroll Change

    Cancel a payroll change

  • Submit Time Sheet

    Submit a time sheet for approval

  • Confirm Time Sheet

    Confirm a time sheet

  • Submit Hiring Employment

    Submit a hiring employment for processing

  • Invite Team Member

    Send invitation to a team member for a hiring employment

  • Hiring Agreement Accepted

    Emitted when a team member accepts their employment or contractor agreement. Maps to OysterHR event `hiring.agreement_accepted`.

  • Hiring Agreement Drafted

    Emitted when a new employment or contractor agreement draft is created for review. Maps to OysterHR event `hiring.agreement_drafted`.

  • Hiring Agreement Signed

    Emitted when an employment or contractor agreement is fully signed by all parties. Maps to OysterHR event `hiring.agreement_signed`.

  • Hiring Agreement Updated

    Emitted when an existing employment or contractor agreement is modified with new terms or details. Maps to OysterHR event `hiring.agreement_updated`.

  • Hiring Agreement Verified

    Emitted when an employment or contractor agreement passes verification checks. Maps to OysterHR event `hiring.agreement_verified`.

  • Hiring Contractor Engaged

    Emitted when a contractor engagement becomes active and the contractor is ready to begin work. Maps to OysterHR event `hiring.contractor_engaged`.

  • Hiring Contractor Submitted

    Emitted when a new contractor hiring request is submitted for processing. Maps to OysterHR event `hiring.contractor_submitted`.

  • Hiring Employment Engaged

    Emitted when an employee engagement becomes active and the employee officially starts their role. Maps to OysterHR event `hiring.employment_engaged`.

  • Hiring Employment Onboarding Completed

    Emitted when a new employee completes all onboarding steps and requirements. Maps to OysterHR event `hiring.employment_onboarding_completed`.

  • Hiring Employment Submitted

    Emitted when a new employee hiring request is submitted for processing. Maps to OysterHR event `hiring.employment_submitted`.

  • Hiring Oyster Invitation Accepted

    Emitted when a team member accepts their invitation to join the Oyster platform. Maps to OysterHR event `hiring.oyster_invitation_accepted`.

  • Hiring Payroll Team Member Engaged

    Emitted when a payroll team member engagement becomes active and payroll processing begins. Maps to OysterHR event `hiring.payroll_team_member_engaged`.

  • Hiring Payroll Team Member Submitted

    Emitted when a new payroll team member hiring request is submitted for processing. Maps to OysterHR event `hiring.payroll_team_member_submitted`.

  • Hiring Task Updated

    Emitted when a hiring-related task is updated, such as a background check or document submission status change. Maps to OysterHR event `hiring.task_updated`.

  • Offboarding Approved

    Emitted when an offboarding request is approved and the termination process can proceed. Maps to OysterHR event `offboarding.approved`.

  • Offboarding Cancelled

    Emitted when a previously initiated offboarding process is cancelled and the engagement continues. Maps to OysterHR event `offboarding.cancelled`.

  • Offboarding Engagement Terminated

    Emitted when an engagement is fully terminated and the team member is offboarded from the company. Maps to OysterHR event `offboarding.engagement_terminated`.

  • Offboarding Initiated

    Emitted when an offboarding process is started for a team member, beginning the termination workflow. Maps to OysterHR event `offboarding.initiated`.

  • Time Off Request Created

    Emitted when a team member submits a new time off request for approval. Maps to OysterHR event `time_off.request_created`.

  • Time Off Request Modified

    Emitted when an existing time off request is modified, such as date or duration changes. Maps to OysterHR event `time_off.request_modified`.

  • Time Off Request Status Changed

    Emitted when a time off request status changes, such as being approved, declined, or cancelled. Maps to OysterHR event `time_off.request_status_changed`.

  • Time Tracking Time Sheet Approved

    Emitted when a submitted time sheet is approved by a manager or administrator. Maps to OysterHR event `time_tracking.time_sheet_approved`.

  • Time Tracking Time Sheet Created

    Emitted when a new time sheet is created for a team member's work period. Maps to OysterHR event `time_tracking.time_sheet_created`.

  • Time Tracking Time Sheet Deleted

    Emitted when a time sheet is deleted from the system. Maps to OysterHR event `time_tracking.time_sheet_deleted`.

  • Time Tracking Time Sheet Entries Modified

    Emitted when individual time entries within a time sheet are added, updated, or removed. Maps to OysterHR event `time_tracking.time_sheet_entries_modified`.

  • Time Tracking Time Sheet Pending Approval

    Emitted when a time sheet is submitted and awaiting manager or administrator approval. Maps to OysterHR event `time_tracking.time_sheet_pending_approval`.

  • Time Tracking Time Sheet Submitted

    Emitted when a team member submits their completed time sheet for the work period. Maps to OysterHR event `time_tracking.time_sheet_submitted`.

  • Engagements Document Uploaded

    Emitted when a new document is uploaded to a team member's engagement record. Maps to OysterHR event `engagements.document_uploaded`.

  • Engagements Document Updated

    Emitted when an existing document on a team member's engagement record is modified. Maps to OysterHR event `engagements.document_updated`.

  • Engagements Document Deleted

    Emitted when a document is removed from a team member's engagement record. Maps to OysterHR event `engagements.document_deleted`.

  • Engagements Payslip Uploaded

    Emitted when a new payslip is uploaded and made available for a team member. Maps to OysterHR event `engagements.payslip_uploaded`.

  • Engagements Payslip Updated

    Emitted when an existing payslip record is modified or corrected. Maps to OysterHR event `engagements.payslip_updated`.

  • Engagements Payslip Deleted

    Emitted when a payslip record is removed from a team member's engagement. Maps to OysterHR event `engagements.payslip_deleted`.

  • Expenses Expense Approved

    Emitted when a submitted expense claim is approved for reimbursement. Maps to OysterHR event `expenses.expense_approved`.

  • Expenses Expense Created

    Emitted when a team member submits a new expense claim for approval. Maps to OysterHR event `expenses.expense_created`.

  • Expenses Expense Declined

    Emitted when a submitted expense claim is declined and will not be reimbursed. Maps to OysterHR event `expenses.expense_declined`.

  • Contract Change Applied

    Emitted when an approved contract change takes effect on the engagement terms. Maps to OysterHR event `contract.change_applied`.

  • Contract Change Approved

    Emitted when a requested contract change is approved and ready to be applied. Maps to OysterHR event `contract.change_approved`.

  • Contract Change Cancelled

    Emitted when a pending contract change request is cancelled before being applied. Maps to OysterHR event `contract.change_cancelled`.

  • Contract Change Requested

    Emitted when a change to an existing contract is requested, such as salary adjustment or role change. Maps to OysterHR event `contract.change_requested`.

  • Contract Change Submitted

    Emitted when a contract change request is formally submitted for review and approval. Maps to OysterHR event `contract.change_submitted`.

  • Contract Change Updated

    Emitted when the details of a pending contract change request are modified before approval. Maps to OysterHR event `contract.change_updated`.

  • Payments Charge Paid

    Emitted when a payment charge is successfully processed and funds are transferred. Maps to OysterHR event `payments.charge_paid`.

  • Payments Charge Failed

    Emitted when a payment charge fails to process due to insufficient funds or other payment issues. Maps to OysterHR event `payments.charge_failed`.

  • Payments Charge Group Paid

    Emitted when a group of payment charges is successfully processed as a batch. Maps to OysterHR event `payments.charge_group_paid`.

Oyster HR AI Agent Use Cases

Connect your AI agent to Oyster HR 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
Job Posting Distribution

Use StackOne to connect your AI agent to your ATS and job boards to automate job posting distribution.

View
GreenhouseLeverAshbySmartRecruitersWorkableJobviteiCIMSTeamtailor
More HRIS & HCM use cases More Recruiting use cases

Set Up Your Oyster HR MCP Server in Minutes

One endpoint. Any framework. Your agent is talking to Oyster HR 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>"
      ]
    }
  }
}

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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

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

Oyster HR MCP Server FAQ

Does StackOne have a Oyster HR MCP server?
Yes. StackOne offers a hosted Oyster HR MCP server with 104 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.
Oyster HR MCP server vs direct API integration — what's the difference?
A Oyster HR MCP server and direct API integration serve different use cases. Direct API integration is for software-to-software — backend code calling Oyster HR. A Oyster HR 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 Oyster HR at runtime. StackOne provides both.
How does Oyster HR authentication work for AI agents?
Oyster HR 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 Oyster HR account; StackOne handles token exchange, storage, and refresh. Credentials never reach the LLM, and each user is isolated via origin_owner_id.
Are Oyster HR MCP tools vulnerable to prompt injection?
Yes — Oyster HR 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 Oyster HR agent and how do I avoid it?
Context bloat happens when Oyster HR tool schemas and API responses eat your Oyster HR agent's memory, preventing it from reasoning effectively. A single Oyster HR 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 Oyster HR agent can access?
Yes — you can limit which actions your Oyster HR 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 Oyster HR MCP server?
Yes — you can create custom agent actions for your Oyster HR MCP server using Connector Builder. It's an integration agent your coding assistant (Claude Code, Cursor, or Copilot) can invoke to research Oyster HR's API, generate production-ready connector YAML, test against the live API, and validate before you ship.
When should I NOT use a Oyster HR MCP server?
Skip a Oyster HR MCP server if your integration is purely software-to-software — direct Oyster HR 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 Oyster HR actions at runtime.
What AI frameworks and AI clients does the StackOne Oyster HR MCP server support?
The StackOne Oyster HR 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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